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Causes of Dollar Spots
27 sections • 0% read
Many homeowners first notice dollar spot when their lawn suddenly looks “peppered” with small, round, straw-colored spots that seem to multiply overnight. Each spot may start about the size of a silver dollar, then merge into larger bleached patches that weaken the turf and ruin an otherwise clean, green surface.
Despite the way it is often typed in searches as “dollar spots”, this problem is not multiple separate issues. It is one specific turf disease known as dollar spot, caused by a group of fungi in the Clarireedia genus (previously Sclerotinia homoeocarpa). Understanding the true causes of dollar spots is critical, because misdiagnosis leads to wasted money on fungicides, repeated outbreaks, and long-term thinning of high-value lawns, sports fields, and golf course turf.
Dollar spot behaves differently from other common lawn diseases like brown patch, leaf spot, and summer patch. It thrives in particular temperature and moisture conditions and is strongly influenced by lawn care practices such as mowing, fertilizing, and irrigation. This guide explains what dollar spot disease is, then digs into what actually causes dollar spots to appear and spread, from environmental triggers and nutrient imbalances to thatch, compaction, and mismanagement. Finally, it outlines advanced prevention strategies so you can break the cycle instead of chasing symptoms year after year.
To stop dollar spots, you first need to understand the specific conditions that favor this fungus. Once you know what is driving the disease in your lawn, you can make targeted changes that reduce risk instead of relying only on fungicides.
If you see small, round, bleached spots about 1 to 3 inches across that coalesce into larger patches, and close-up inspection shows tan leaf blades with reddish-brown borders and bleached centers, that typically points to dollar spot. Confirm on a cool, humid morning by looking for fine, white, cottony mycelium in the dew on affected areas, and by checking that the grass crowns are still alive and not rotted.
The core causes of dollar spots are extended leaf wetness, moderate temperatures (roughly 60-85°F), and low nitrogen fertility combined with stress from mowing and traffic. The fix usually requires three coordinated steps: adjust fertilization to correct nitrogen deficiency, change watering so the lawn dries by late morning, and improve airflow and thatch management to reduce the fungus’s habitat. Avoid aggressive dethatching or heavy fungicide use without confirming the disease first, because those can stress turf or create resistance.
After you improve cultural conditions, new spots generally stop appearing within 7 to 14 days, although existing bleached leaves must be replaced by new growth over several weeks. In severe cases, a timely fungicide application, combined with these cultural fixes, can protect new foliage for 14 to 21 days during peak disease pressure. Plan to reassess fertility and watering before the next high-risk window in late spring or early fall to prevent recurrence instead of just reacting.
Dollar spot is a foliar turfgrass disease caused by Clarireedia species fungi. It attacks the leaves and sometimes the crowns of turfgrass but does not typically rot the roots. It is one of the most common and economically important diseases of cool-season turf across North America and also affects some warm-season grasses under intensive management.
The classic symptom is a small, round, straw-colored or bleached spot in the lawn, often between 1 and 3 inches across at first. On closely mowed golf greens, spots can be close to the size of a silver dollar, which is how the disease got its name. On higher-mowed home lawns, the individual spots are often larger and irregular, and over time they merge into bigger, irregular patches several inches to several feet across.
If you look closely at individual blades inside a spot, you will often see lesions that are tan or bleached in the center with distinct reddish-brown borders. On many grasses, the lesion may pinch the leaf in the middle, creating an “hourglass” or “strawy” look where the leaf collapses and dries out. These foliar symptoms distinguish dollar spot from other diseases like brown patch, which usually causes larger, more circular patches and a different lesion pattern.
Homeowners frequently search for the “causes of dollar spots” or say their lawn has “dollar spots,” implying many separate spots. In reality, these individual spots are just different infection centers caused by the same disease organism. It is more accurate to talk about the causes of dollar spot disease and the conditions that allow it to express as many circular spots across your lawn.
Dollar spot has a very wide host range compared to many other turf diseases. Nearly all commonly used cool-season lawn and turf species can be affected, though severity differs by species and variety.
Among cool-season grasses, the most susceptible include:
Among warm-season grasses, dollar spot is less common in typical home lawn management but can be quite significant where turf is cut low and maintained intensively, such as:
In most home lawns, the grass types most frequently seen with dollar spot are Kentucky bluegrass, perennial ryegrass, tall fescue mixes, and occasionally fine fescue lawns. Golf courses, by contrast, see heavy pressure on creeping bentgrass and annual bluegrass, which are highly susceptible and cut at very low heights that favor disease development.
Understanding why dollar spots keep coming back requires a look at the pathogen’s life cycle. The Clarireedia fungus survives between outbreaks in infected leaf tissue, thatch, and surface soil as small, dormant structures or inactive mycelium. It does not need a living host to survive the winter; it can persist in dead thatch and debris.
When conditions become favorable - typically when nighttime temperatures rise into the 50s and 60s Fahrenheit and humidity stays high - the fungus becomes active. It moves onto moist leaf blades, germinates, and penetrates through natural openings or wounds. Extended periods of leaf wetness are critical; the fungus needs several consecutive hours of moisture on leaves to infect successfully.
Dollar spot is very active in the overnight and early morning hours. Infection usually happens at night when leaves are wet with dew and temperatures are moderate. By morning, you may see fresh “blighted” spots that were not noticeable the day before. On humid mornings with heavy dew, you can often see fine, white, cottony mycelium on the leaf surface within infected spots. This mycelium disappears as the grass dries later in the day, which is why early-morning inspection is so important.
The disease cycle can repeat many times in a season when conditions remain favorable. Because the fungus overwinters in thatch and debris, lawns with thick thatch or a history of dollar spot have a larger reservoir of inoculum ready to flare up as soon as weather patterns and management practices again align in the fungus’s favor.
Dollar spot activity is strongly tied to temperature and humidity. It typically becomes a problem when average daily temperatures are in the 60-85°F (15-29°C) range, with peak activity around 70°F (21°C). This is why cool-season lawns often see outbreaks in late spring and again in early to mid fall, when days are mild and nights are cool but not cold.
Relative humidity is just as important as temperature. High nighttime humidity keeps leaf surfaces wet for long periods, especially when wind is light and air movement over the lawn is limited. When evening and nighttime humidity consistently stay above roughly 85 percent, dew forms easily and lingers longer, giving the fungus more time to infect.
Seasonally, that means:
One of the simplest tools a homeowner can use is a weather app. When you see a pattern of nighttime lows in the 50-60°F range with calm, humid mornings and several days of heavy dew in a row, that is a clear risk period for dollar spots. If those conditions align with low nitrogen and recent mowing stress, disease pressure typically spikes.
While many turf diseases require moisture, dollar spot is especially sensitive to the duration of leaf wetness. The fungus needs leaves to remain wet long enough for spores or mycelium to germinate, grow, and penetrate. As a rule of thumb, when leaf wetness exceeds about 8 to 10 hours on a regular basis, the risk of infection rises sharply.
Early morning dew is the main driver of this extended wetness. In many lawns, dew forms in the late evening and persists well into midmorning. When dew remains past 9 or 10 a.m. several days in a row, those long wet periods create ideal conditions for dollar spot to infect and damage new leaves. Closely mowed turf, like golf greens or low-cut lawns, generally holds dew longer and more uniformly than higher-cut grass, which is why ultra-low mowing heights are strongly associated with severe dollar spot.
In addition to natural dew, several management practices increase leaf wetness duration:
To break this moisture cycle, turf managers often incorporate “dew removal” routines, especially on high-value turf. Simple methods include dragging a light hose or rope across the lawn, using a leaf blower to move air over the canopy, or lightly rolling greens in the early morning. For homeowners, simply avoiding late evening watering and using a blower to knock dew off shaded trouble spots can significantly reduce the length of time leaves stay wet during critical infection windows.
Among all management-related causes of dollar spots, chronic low nitrogen fertility stands out. Research and field experience consistently show that under-fertilized turf is much more susceptible to dollar spot. Low nitrogen results in thin, slow-growing turf with fewer leaves and reduced ability to recover from foliar damage. It also leads to higher concentrations of certain amino acids that can favor fungal growth.
If you see dollar spots mainly in pale or yellowish areas while greener, better-fed areas stay clean, this typically points to nitrogen deficiency as a major contributing factor. A common threshold used by many turf programs is that cool-season lawns receiving less than about 2 to 3 pounds of nitrogen per 1,000 square feet per growing season are at higher risk, particularly if applications are infrequent and poorly timed.
Other nutrient imbalances can also play a role. Turf that is low in potassium often has weaker cell walls and lower stress tolerance, which can indirectly increase dollar spot severity. Conversely, excessive nitrogen can reduce dollar spot in the short term but may favor other diseases like brown patch in warm, humid weather. The goal is balanced fertility based on a soil test, not simply “more fertilizer.”
To confirm whether nutrition is contributing to your dollar spot problem, check these indicators:
Correcting nitrogen deficiency in cool-season lawns typically involves applying about 0.5 to 0.75 pounds of nitrogen per 1,000 square feet in late spring or early fall when the grass is actively growing. Avoid exceeding 1 pound of nitrogen per 1,000 square feet in a single application, as heavier doses can burn grass or push excessive top growth.
Mowing practices significantly influence the causes of dollar spots because they affect turf stress, leaf wetness, and thatch. Very low mowing heights create short, thin leaves that are easily penetrated by the fungus and that stay wet longer in the morning dew. Golf greens mowed at 0.1 to 0.15 inches are classic examples where dollar spot thrives with minimal margin for error.
In home lawns, cutting cool-season grasses like Kentucky bluegrass or fescue below about 2.5 inches height increases susceptibility. Shorter grass has less leaf area for photosynthesis, weaker roots, and less ability to grow out of foliar damage. Scalping or removing more than one-third of the leaf blade in a single cut creates additional wounds and stress that the fungus can exploit.
Mowing equipment condition matters as well. Dull blades tear leaves instead of cutting them cleanly, creating ragged edges that are more vulnerable to infection. If you see shredded leaf tips throughout the lawn, this indicates your mower blades need sharpening. Regular sharpening, usually at least once or twice per season for home users, is a simple way to reduce stress and disease entry points.
To reduce dollar spot risk through mowing:
Thatch is a layer of dead and living stems, roots, and other organic material that accumulates between the soil surface and the green leaf canopy. A thin thatch layer is normal, but when it exceeds about 0.5 inch, it creates a spongy, moisture-holding mat that is ideal for dollar spot. The fungus overwinters and survives in this organic material, so thicker thatch means more inoculum and a more humid microclimate at the turf base.
Compacted soils are another underlying cause. Compaction reduces root growth, drainage, and oxygen levels in the soil, stressing turf and increasing its vulnerability to disease. Water tends to sit near the surface instead of draining away, which prolongs leaf and thatch wetness. If a screwdriver or soil probe is difficult to push more than 3 to 4 inches into the soil, that typically indicates compaction and potential drainage limitations.
Poor air movement across the lawn combines with thatch and compaction to raise disease pressure even further. Areas shielded by trees, shrubs, or buildings dry more slowly after dew or irrigation. Shade can also keep temperatures in the “sweet spot” for dollar spot longer during the day.
Key signs that thatch, compaction, or airflow are contributing to your problem include:
Core aeration once or twice a year on compacted soils, along with topdressing and modest dethatching when thatch exceeds 0.5 inch, are proven cultural practices to improve root health and reduce the microclimate that favors dollar spot. Thinning low limbs to increase airflow around trouble spots can also help lawns dry faster after dew.
Irrigation schedules and methods can either suppress or promote dollar spot. The most common mistake homeowners make is frequent, shallow watering that wets the leaves but does not soak the soil deeply. When this irrigation happens late in the evening or at night, it dramatically extends the period of leaf wetness and sets up ideal conditions for the fungus.
Healthy cool-season lawns generally need about 1 to 1.5 inches of water per week from rain plus irrigation during active growth. The most disease-resistant way to provide this is deep and infrequent watering, for example 0.5 inches applied twice per week in the early morning, so the soil is moistened to 4 to 6 inches deep and the leaves have time to dry by midmorning.
If you suspect watering is contributing to dollar spot, look for these patterns:
Adjusting your irrigation controller to finish cycles between 3 and 6 a.m. is an effective way to reduce leaf wetness duration. For manual watering, avoid late evening sessions during known high-risk weather patterns. Check irrigation uniformity as well; dry spots can weaken turf and make it more susceptible even as nearby overwatered areas favor the fungus directly.
Historically, dollar spot was attributed to a single species, Sclerotinia homoeocarpa. Research has since reclassified the pathogen into several Clarireedia species. From a homeowner’s perspective, the practical takeaway is that many different strains exist, some of which may be more aggressive or more tolerant of fungicides than others.
Lawns with a long history of dollar spot often have a high inoculum load, meaning there is a large resident population of the fungus waiting in thatch and debris. Even when you correct watering and fertility, this reservoir means the disease can reappear quickly as soon as conditions swing back into the favorable temperature and humidity range. In such situations, the causes of dollar spots are not only environmental stress but also the sheer amount of fungus present.
On intensively managed turf where fungicides are frequently used, another complication is fungicide resistance. Repeated applications of the same chemical class can select for dollar spot strains that survive treatment. Over time, control appears to “fade” even when labeled products and rates are followed correctly. For homeowners, this is less common but can still occur where the same fungicide is used year after year without rotation.
Fungicides are valuable tools for protecting high-value turf, but misusing them can indirectly worsen the long-term causes of dollar spots. Common issues include:
On home lawns, fungicides are usually most effective when used as part of an integrated plan during known high-risk periods, rather than as emergency treatments after severe symptoms appear. Always read and follow label directions, including reapplication intervals and total seasonal limits. Rotating among different fungicide classes, where available for homeowner use, is important to slow the development of resistance.
The community of microorganisms in the soil and thatch, often called the soil microbiome, influences disease dynamics. Healthy, biologically active soils tend to have greater populations of beneficial microbes that compete with or antagonize pathogens. Conversely, heavily compacted, low-organic-matter soils with limited microbial diversity may offer fewer natural checks on dollar spot fungi.
While the science is still evolving, practices that enhance soil health - such as adding compost topdressings, reducing unnecessary pesticide use, and minimizing chronic wetness - may indirectly reduce disease pressure over time. However, these measures should be viewed as long-term support for turf resilience rather than quick fixes, and they must be combined with direct management of the key causes of dollar spots like leaf wetness and fertility.
Because the right solution depends on accurate diagnosis, it is important to distinguish dollar spot from other diseases that also cause bleached or brown patches. Dollar spot usually appears as many small spots scattered across the lawn, whereas some other diseases create fewer, larger patches.
To diagnose dollar spot, use this field checklist:
If you see these signs, you are likely dealing with dollar spot rather than another issue. For absolute confirmation, you can submit a sample to a local turf diagnostic lab or extension service.
Several diseases are often confused with dollar spot because they also create off-color patches. Knowing a few key differences helps you avoid misdirected treatments.
Brown patch tends to form larger, roughly circular patches that can be 6 inches to several feet in diameter, often with a darker “smoke ring” around the edge in the early morning. It favors warmer night temperatures, typically above 65°F, combined with high humidity and lush nitrogen levels. Leaf lesions are more irregular and water-soaked than the distinct hourglass pattern of dollar spot.
Leaf spot and melting out cause small, dark spots or streaks on leaves that can coalesce into larger blighted areas. They often impact Kentucky bluegrass in spring under cool, wet conditions and can progress to crown and root damage. The leaf lesions are usually darker and more “spotted” than dollar spot’s bleached centers with reddish borders.
Summer patch is a root and crown disease that causes wilted, sunken patches and rings in mid to late summer, often when soil temperatures exceed 65°F. Affected plants pull readily from the soil with rotted crown tissue. Unlike dollar spot, which is mainly a foliar disease, summer patch damage originates below ground and is not associated with the characteristic small, straw-colored spots.
If you see small bleached spots with the classic leaf lesion pattern in the 60-80°F range and extended dew, the causes of dollar spots are far more likely than these other diseases. Confirm with the morning mycelium check, then tailor your management accordingly.
A central strategy for controlling dollar spot is correcting nutrient deficiencies, especially nitrogen. For cool-season home lawns, a common program is to supply 3 to 4 pounds of nitrogen per 1,000 square feet per year, split into 3 or 4 applications during active growth periods. In regions with hot summers, heavier emphasis is often placed on fall fertilization to avoid excessive summer growth.
When dollar spot is active due to low nitrogen, an application of 0.5 to 0.75 pounds of nitrogen per 1,000 square feet can help the turf grow out of lesions and thicken the stand. Slow-release nitrogen sources are often preferred for steady feeding and reduced burn risk, especially at the upper end of this rate range. Always calibrate your spreader and measure lawn area accurately to avoid over- or under-application.
Potassium is another nutrient to consider. Where soil tests show low or medium potassium levels, supplementing according to recommendations can strengthen cell walls and improve stress tolerance. Be cautious with high phosphorus applications unless a soil test indicates need, as excessive phosphorus can contribute to environmental issues and is not a direct solution to dollar spot.
Reworking your irrigation schedule can directly target one of the primary causes of dollar spots: extended leaf wetness. The goal is for turf to receive enough water to maintain healthy growth without keeping leaf surfaces wet overnight.
Start by determining how much water your sprinklers apply. Place several straight-sided containers, like tuna cans, in the lawn and run your system for 15 minutes. Measure the depth of water in each can and average it. If you find that 15 minutes equals 0.25 inches, for example, then a 60-minute run delivers about 1 inch of water. Use this information to schedule two deep, early-morning irrigations per week during dry spells, aiming for a total of about 1 to 1.5 inches of water per week including rainfall.
Set automatic systems so watering finishes between about 3 a.m. and 6 a.m. This timing allows dew to mix with irrigation, but still gives the sun and breeze several hours to dry the leaves by late morning. Avoid routine evening or nighttime watering during high-risk periods when temperatures and humidity are favorable for dollar spot.
To lower inoculum levels and improve drying around the turf base, focus on thatch, soil structure, and air movement. For lawns with more than 0.5 inch of thatch, consider light power raking or verticutting in early fall or spring when the turf can quickly recover. Avoid overly aggressive dethatching in hot or dry conditions because it can stress turf and temporarily increase vulnerability.
Core aeration, which removes plugs of soil and thatch, is one of the most practical tools for homeowners. Aerating once per year on compacted, high-traffic lawns or once every 1 to 2 years on less compacted turf helps improve infiltration, root depth, and oxygen levels, all of which make turf more resilient to disease. Leaving the cores to break down naturally or dragging them to crumble can also help dilute thatch with soil.
Where dollar spot is consistently worse in shaded or sheltered zones, evaluate opportunities to improve airflow. Pruning lower tree branches, selectively thinning densely planted beds, or opening narrow wind channels between structures can help these areas dry faster after dew or irrigation. These changes often provide benefits beyond disease control, including reduced moss and algae on hard surfaces.
For some lawns, especially high-value turf or properties with a chronic history of severe dollar spot, cultural changes alone may not be enough to prevent damage during peak pressure periods. In those cases, integrating fungicides as a preventive or early-curative tool can be justified.
If you choose to use fungicides, keep these principles in mind:
Always check that any product you choose is labeled for your grass species, for dollar spot, and for residential use if you are treating a home lawn. Wear appropriate protective equipment and follow all reentry intervals, especially where children or pets use the lawn regularly.
Many online resources mention that dollar spot is “caused by a fungus” and suggest a fungicide, but they often overlook critical diagnostic and management details. Avoid these common pitfalls to save time and money.
Skipping confirmation of the disease is a frequent error. Pale patches can also be drought stress, grub damage, or nutrient deficiency. If you treat drought or grubs with a fungicide, you will see no improvement and waste money. Always check for the distinctive leaf lesions and early-morning mycelium before concluding you have dollar spot.
Ignoring nitrogen status is another big oversight. Some guides treat fungicides as the main or only solution. In reality, if your lawn is underfed, dollar spot will keep returning as soon as fungicides wear off. Reviewing your annual nitrogen totals and using a soil test to guide potassium adjustments are key steps that many summaries simply skip.
Overwatering at the wrong time of day is also underemphasized. Guides may tell you “do not overwater,” but do not explain that 0.25 inches applied at 9 p.m. can be more damaging from a disease standpoint than 0.75 inches applied at 5 a.m. The combination of water amount, frequency, and timing is what matters for the causes of dollar spots that relate to leaf wetness.
Finally, failing to check for compaction and thatch leaves a big gap. If you never perform the simple screwdriver test for compaction or measure your thatch layer, you may be missing two of the most manageable underlying causes that make your lawn a permanent home for dollar spot fungi.
Turning this information into action is easier if you think seasonally. While climates differ, a general cool-season lawn plan might look like this:
Early spring (soil temps rising to 50-55°F): Perform a soil test if it has been more than 3 years. Sharpen mower blades. Assess thatch and compaction by cutting a small plug and performing a screwdriver test. Begin deep, infrequent irrigation only when needed.
Late spring (daily highs in 60s-70s°F): This is a high-risk dollar spot window. Ensure nitrogen applications are on track, typically 0.5 to 1.0 pound of nitrogen per 1,000 square feet depending on your annual plan. Check mowing height and adjust to at least 2.5 to 3 inches. Watch for persistent dew and spots, and perform early-morning mycelium checks. If your lawn has a history of severe dollar spot, consider a preventive fungicide during prolonged mild, humid stretches.
Summer: Focus on irrigation timing and depth. If weather is hot, avoid heavy nitrogen applications that could stress turf and favor other diseases. Monitor shaded or sheltered areas that stay moist. If dollar spot appears, reassess watering and traffic patterns.
Early fall: As temperatures cool back into the dollar spot range, apply another 0.5 to 1.0 pound of nitrogen per 1,000 square feet to support recovery and thickening. Fall is also a good time for core aeration and, if needed, moderate dethatching. Overseed thin areas with appropriate grass species and varieties with improved disease resistance.
Late fall: Apply a “winterizer” nitrogen application if recommended for your region, usually about 0.5 to 1.0 pound of nitrogen per 1,000 square feet. This supports root growth and early spring green-up, which in turn boosts turf vigor and disease resistance the following year.
By addressing the environmental, cultural, and biological causes of dollar spots across the year, you shift your lawn from a high-risk environment to one where dollar spot struggles to gain a foothold. Fungicides, if needed, then become an occasional tool instead of a constant crutch.
Dollar spot is not a mysterious random event. When you see small, straw-colored spots spreading across your lawn, you are looking at the visible outcome of specific causes: moderate temperatures, prolonged leaf wetness, low nitrogen, stress from mowing and compaction, and an active fungal population living in thatch and debris. Controlling the disease long term means systematically addressing these causes, not just spraying them away for a few weeks.
If you start by properly diagnosing the disease, then methodically improve fertility, mowing height, watering schedules, and soil structure, you can dramatically reduce the frequency and severity of outbreaks. For a deeper dive into building a stronger lawn overall, check out our guide on fall fertilizer timing to align nutrition with your grass’s natural growth cycles.
Look for fertilizers with a balanced analysis and at least 30 percent slow-release nitrogen, plan irrigation to deliver 1 to 1.5 inches of water per week in the early morning, and schedule annual aeration on compacted soils. These steps not only tackle the causes of dollar spots but also build a thicker, more resilient lawn that resists many other problems as well.
Many homeowners first notice dollar spot when their lawn suddenly looks “peppered” with small, round, straw-colored spots that seem to multiply overnight. Each spot may start about the size of a silver dollar, then merge into larger bleached patches that weaken the turf and ruin an otherwise clean, green surface.
Despite the way it is often typed in searches as “dollar spots”, this problem is not multiple separate issues. It is one specific turf disease known as dollar spot, caused by a group of fungi in the Clarireedia genus (previously Sclerotinia homoeocarpa). Understanding the true causes of dollar spots is critical, because misdiagnosis leads to wasted money on fungicides, repeated outbreaks, and long-term thinning of high-value lawns, sports fields, and golf course turf.
Dollar spot behaves differently from other common lawn diseases like brown patch, leaf spot, and summer patch. It thrives in particular temperature and moisture conditions and is strongly influenced by lawn care practices such as mowing, fertilizing, and irrigation. This guide explains what dollar spot disease is, then digs into what actually causes dollar spots to appear and spread, from environmental triggers and nutrient imbalances to thatch, compaction, and mismanagement. Finally, it outlines advanced prevention strategies so you can break the cycle instead of chasing symptoms year after year.
To stop dollar spots, you first need to understand the specific conditions that favor this fungus. Once you know what is driving the disease in your lawn, you can make targeted changes that reduce risk instead of relying only on fungicides.
If you see small, round, bleached spots about 1 to 3 inches across that coalesce into larger patches, and close-up inspection shows tan leaf blades with reddish-brown borders and bleached centers, that typically points to dollar spot. Confirm on a cool, humid morning by looking for fine, white, cottony mycelium in the dew on affected areas, and by checking that the grass crowns are still alive and not rotted.
The core causes of dollar spots are extended leaf wetness, moderate temperatures (roughly 60-85°F), and low nitrogen fertility combined with stress from mowing and traffic. The fix usually requires three coordinated steps: adjust fertilization to correct nitrogen deficiency, change watering so the lawn dries by late morning, and improve airflow and thatch management to reduce the fungus’s habitat. Avoid aggressive dethatching or heavy fungicide use without confirming the disease first, because those can stress turf or create resistance.
After you improve cultural conditions, new spots generally stop appearing within 7 to 14 days, although existing bleached leaves must be replaced by new growth over several weeks. In severe cases, a timely fungicide application, combined with these cultural fixes, can protect new foliage for 14 to 21 days during peak disease pressure. Plan to reassess fertility and watering before the next high-risk window in late spring or early fall to prevent recurrence instead of just reacting.
Dollar spot is a foliar turfgrass disease caused by Clarireedia species fungi. It attacks the leaves and sometimes the crowns of turfgrass but does not typically rot the roots. It is one of the most common and economically important diseases of cool-season turf across North America and also affects some warm-season grasses under intensive management.
The classic symptom is a small, round, straw-colored or bleached spot in the lawn, often between 1 and 3 inches across at first. On closely mowed golf greens, spots can be close to the size of a silver dollar, which is how the disease got its name. On higher-mowed home lawns, the individual spots are often larger and irregular, and over time they merge into bigger, irregular patches several inches to several feet across.
If you look closely at individual blades inside a spot, you will often see lesions that are tan or bleached in the center with distinct reddish-brown borders. On many grasses, the lesion may pinch the leaf in the middle, creating an “hourglass” or “strawy” look where the leaf collapses and dries out. These foliar symptoms distinguish dollar spot from other diseases like brown patch, which usually causes larger, more circular patches and a different lesion pattern.
Homeowners frequently search for the “causes of dollar spots” or say their lawn has “dollar spots,” implying many separate spots. In reality, these individual spots are just different infection centers caused by the same disease organism. It is more accurate to talk about the causes of dollar spot disease and the conditions that allow it to express as many circular spots across your lawn.
Dollar spot has a very wide host range compared to many other turf diseases. Nearly all commonly used cool-season lawn and turf species can be affected, though severity differs by species and variety.
Among cool-season grasses, the most susceptible include:
Among warm-season grasses, dollar spot is less common in typical home lawn management but can be quite significant where turf is cut low and maintained intensively, such as:
In most home lawns, the grass types most frequently seen with dollar spot are Kentucky bluegrass, perennial ryegrass, tall fescue mixes, and occasionally fine fescue lawns. Golf courses, by contrast, see heavy pressure on creeping bentgrass and annual bluegrass, which are highly susceptible and cut at very low heights that favor disease development.
Understanding why dollar spots keep coming back requires a look at the pathogen’s life cycle. The Clarireedia fungus survives between outbreaks in infected leaf tissue, thatch, and surface soil as small, dormant structures or inactive mycelium. It does not need a living host to survive the winter; it can persist in dead thatch and debris.
When conditions become favorable - typically when nighttime temperatures rise into the 50s and 60s Fahrenheit and humidity stays high - the fungus becomes active. It moves onto moist leaf blades, germinates, and penetrates through natural openings or wounds. Extended periods of leaf wetness are critical; the fungus needs several consecutive hours of moisture on leaves to infect successfully.
Dollar spot is very active in the overnight and early morning hours. Infection usually happens at night when leaves are wet with dew and temperatures are moderate. By morning, you may see fresh “blighted” spots that were not noticeable the day before. On humid mornings with heavy dew, you can often see fine, white, cottony mycelium on the leaf surface within infected spots. This mycelium disappears as the grass dries later in the day, which is why early-morning inspection is so important.
The disease cycle can repeat many times in a season when conditions remain favorable. Because the fungus overwinters in thatch and debris, lawns with thick thatch or a history of dollar spot have a larger reservoir of inoculum ready to flare up as soon as weather patterns and management practices again align in the fungus’s favor.
Dollar spot activity is strongly tied to temperature and humidity. It typically becomes a problem when average daily temperatures are in the 60-85°F (15-29°C) range, with peak activity around 70°F (21°C). This is why cool-season lawns often see outbreaks in late spring and again in early to mid fall, when days are mild and nights are cool but not cold.
Relative humidity is just as important as temperature. High nighttime humidity keeps leaf surfaces wet for long periods, especially when wind is light and air movement over the lawn is limited. When evening and nighttime humidity consistently stay above roughly 85 percent, dew forms easily and lingers longer, giving the fungus more time to infect.
Seasonally, that means:
One of the simplest tools a homeowner can use is a weather app. When you see a pattern of nighttime lows in the 50-60°F range with calm, humid mornings and several days of heavy dew in a row, that is a clear risk period for dollar spots. If those conditions align with low nitrogen and recent mowing stress, disease pressure typically spikes.
While many turf diseases require moisture, dollar spot is especially sensitive to the duration of leaf wetness. The fungus needs leaves to remain wet long enough for spores or mycelium to germinate, grow, and penetrate. As a rule of thumb, when leaf wetness exceeds about 8 to 10 hours on a regular basis, the risk of infection rises sharply.
Early morning dew is the main driver of this extended wetness. In many lawns, dew forms in the late evening and persists well into midmorning. When dew remains past 9 or 10 a.m. several days in a row, those long wet periods create ideal conditions for dollar spot to infect and damage new leaves. Closely mowed turf, like golf greens or low-cut lawns, generally holds dew longer and more uniformly than higher-cut grass, which is why ultra-low mowing heights are strongly associated with severe dollar spot.
In addition to natural dew, several management practices increase leaf wetness duration:
To break this moisture cycle, turf managers often incorporate “dew removal” routines, especially on high-value turf. Simple methods include dragging a light hose or rope across the lawn, using a leaf blower to move air over the canopy, or lightly rolling greens in the early morning. For homeowners, simply avoiding late evening watering and using a blower to knock dew off shaded trouble spots can significantly reduce the length of time leaves stay wet during critical infection windows.
Among all management-related causes of dollar spots, chronic low nitrogen fertility stands out. Research and field experience consistently show that under-fertilized turf is much more susceptible to dollar spot. Low nitrogen results in thin, slow-growing turf with fewer leaves and reduced ability to recover from foliar damage. It also leads to higher concentrations of certain amino acids that can favor fungal growth.
If you see dollar spots mainly in pale or yellowish areas while greener, better-fed areas stay clean, this typically points to nitrogen deficiency as a major contributing factor. A common threshold used by many turf programs is that cool-season lawns receiving less than about 2 to 3 pounds of nitrogen per 1,000 square feet per growing season are at higher risk, particularly if applications are infrequent and poorly timed.
Other nutrient imbalances can also play a role. Turf that is low in potassium often has weaker cell walls and lower stress tolerance, which can indirectly increase dollar spot severity. Conversely, excessive nitrogen can reduce dollar spot in the short term but may favor other diseases like brown patch in warm, humid weather. The goal is balanced fertility based on a soil test, not simply “more fertilizer.”
To confirm whether nutrition is contributing to your dollar spot problem, check these indicators:
Correcting nitrogen deficiency in cool-season lawns typically involves applying about 0.5 to 0.75 pounds of nitrogen per 1,000 square feet in late spring or early fall when the grass is actively growing. Avoid exceeding 1 pound of nitrogen per 1,000 square feet in a single application, as heavier doses can burn grass or push excessive top growth.
Mowing practices significantly influence the causes of dollar spots because they affect turf stress, leaf wetness, and thatch. Very low mowing heights create short, thin leaves that are easily penetrated by the fungus and that stay wet longer in the morning dew. Golf greens mowed at 0.1 to 0.15 inches are classic examples where dollar spot thrives with minimal margin for error.
In home lawns, cutting cool-season grasses like Kentucky bluegrass or fescue below about 2.5 inches height increases susceptibility. Shorter grass has less leaf area for photosynthesis, weaker roots, and less ability to grow out of foliar damage. Scalping or removing more than one-third of the leaf blade in a single cut creates additional wounds and stress that the fungus can exploit.
Mowing equipment condition matters as well. Dull blades tear leaves instead of cutting them cleanly, creating ragged edges that are more vulnerable to infection. If you see shredded leaf tips throughout the lawn, this indicates your mower blades need sharpening. Regular sharpening, usually at least once or twice per season for home users, is a simple way to reduce stress and disease entry points.
To reduce dollar spot risk through mowing:
Thatch is a layer of dead and living stems, roots, and other organic material that accumulates between the soil surface and the green leaf canopy. A thin thatch layer is normal, but when it exceeds about 0.5 inch, it creates a spongy, moisture-holding mat that is ideal for dollar spot. The fungus overwinters and survives in this organic material, so thicker thatch means more inoculum and a more humid microclimate at the turf base.
Compacted soils are another underlying cause. Compaction reduces root growth, drainage, and oxygen levels in the soil, stressing turf and increasing its vulnerability to disease. Water tends to sit near the surface instead of draining away, which prolongs leaf and thatch wetness. If a screwdriver or soil probe is difficult to push more than 3 to 4 inches into the soil, that typically indicates compaction and potential drainage limitations.
Poor air movement across the lawn combines with thatch and compaction to raise disease pressure even further. Areas shielded by trees, shrubs, or buildings dry more slowly after dew or irrigation. Shade can also keep temperatures in the “sweet spot” for dollar spot longer during the day.
Key signs that thatch, compaction, or airflow are contributing to your problem include:
Core aeration once or twice a year on compacted soils, along with topdressing and modest dethatching when thatch exceeds 0.5 inch, are proven cultural practices to improve root health and reduce the microclimate that favors dollar spot. Thinning low limbs to increase airflow around trouble spots can also help lawns dry faster after dew.
Irrigation schedules and methods can either suppress or promote dollar spot. The most common mistake homeowners make is frequent, shallow watering that wets the leaves but does not soak the soil deeply. When this irrigation happens late in the evening or at night, it dramatically extends the period of leaf wetness and sets up ideal conditions for the fungus.
Healthy cool-season lawns generally need about 1 to 1.5 inches of water per week from rain plus irrigation during active growth. The most disease-resistant way to provide this is deep and infrequent watering, for example 0.5 inches applied twice per week in the early morning, so the soil is moistened to 4 to 6 inches deep and the leaves have time to dry by midmorning.
If you suspect watering is contributing to dollar spot, look for these patterns:
Adjusting your irrigation controller to finish cycles between 3 and 6 a.m. is an effective way to reduce leaf wetness duration. For manual watering, avoid late evening sessions during known high-risk weather patterns. Check irrigation uniformity as well; dry spots can weaken turf and make it more susceptible even as nearby overwatered areas favor the fungus directly.
Historically, dollar spot was attributed to a single species, Sclerotinia homoeocarpa. Research has since reclassified the pathogen into several Clarireedia species. From a homeowner’s perspective, the practical takeaway is that many different strains exist, some of which may be more aggressive or more tolerant of fungicides than others.
Lawns with a long history of dollar spot often have a high inoculum load, meaning there is a large resident population of the fungus waiting in thatch and debris. Even when you correct watering and fertility, this reservoir means the disease can reappear quickly as soon as conditions swing back into the favorable temperature and humidity range. In such situations, the causes of dollar spots are not only environmental stress but also the sheer amount of fungus present.
On intensively managed turf where fungicides are frequently used, another complication is fungicide resistance. Repeated applications of the same chemical class can select for dollar spot strains that survive treatment. Over time, control appears to “fade” even when labeled products and rates are followed correctly. For homeowners, this is less common but can still occur where the same fungicide is used year after year without rotation.
Fungicides are valuable tools for protecting high-value turf, but misusing them can indirectly worsen the long-term causes of dollar spots. Common issues include:
On home lawns, fungicides are usually most effective when used as part of an integrated plan during known high-risk periods, rather than as emergency treatments after severe symptoms appear. Always read and follow label directions, including reapplication intervals and total seasonal limits. Rotating among different fungicide classes, where available for homeowner use, is important to slow the development of resistance.
The community of microorganisms in the soil and thatch, often called the soil microbiome, influences disease dynamics. Healthy, biologically active soils tend to have greater populations of beneficial microbes that compete with or antagonize pathogens. Conversely, heavily compacted, low-organic-matter soils with limited microbial diversity may offer fewer natural checks on dollar spot fungi.
While the science is still evolving, practices that enhance soil health - such as adding compost topdressings, reducing unnecessary pesticide use, and minimizing chronic wetness - may indirectly reduce disease pressure over time. However, these measures should be viewed as long-term support for turf resilience rather than quick fixes, and they must be combined with direct management of the key causes of dollar spots like leaf wetness and fertility.
Because the right solution depends on accurate diagnosis, it is important to distinguish dollar spot from other diseases that also cause bleached or brown patches. Dollar spot usually appears as many small spots scattered across the lawn, whereas some other diseases create fewer, larger patches.
To diagnose dollar spot, use this field checklist:
If you see these signs, you are likely dealing with dollar spot rather than another issue. For absolute confirmation, you can submit a sample to a local turf diagnostic lab or extension service.
Several diseases are often confused with dollar spot because they also create off-color patches. Knowing a few key differences helps you avoid misdirected treatments.
Brown patch tends to form larger, roughly circular patches that can be 6 inches to several feet in diameter, often with a darker “smoke ring” around the edge in the early morning. It favors warmer night temperatures, typically above 65°F, combined with high humidity and lush nitrogen levels. Leaf lesions are more irregular and water-soaked than the distinct hourglass pattern of dollar spot.
Leaf spot and melting out cause small, dark spots or streaks on leaves that can coalesce into larger blighted areas. They often impact Kentucky bluegrass in spring under cool, wet conditions and can progress to crown and root damage. The leaf lesions are usually darker and more “spotted” than dollar spot’s bleached centers with reddish borders.
Summer patch is a root and crown disease that causes wilted, sunken patches and rings in mid to late summer, often when soil temperatures exceed 65°F. Affected plants pull readily from the soil with rotted crown tissue. Unlike dollar spot, which is mainly a foliar disease, summer patch damage originates below ground and is not associated with the characteristic small, straw-colored spots.
If you see small bleached spots with the classic leaf lesion pattern in the 60-80°F range and extended dew, the causes of dollar spots are far more likely than these other diseases. Confirm with the morning mycelium check, then tailor your management accordingly.
A central strategy for controlling dollar spot is correcting nutrient deficiencies, especially nitrogen. For cool-season home lawns, a common program is to supply 3 to 4 pounds of nitrogen per 1,000 square feet per year, split into 3 or 4 applications during active growth periods. In regions with hot summers, heavier emphasis is often placed on fall fertilization to avoid excessive summer growth.
When dollar spot is active due to low nitrogen, an application of 0.5 to 0.75 pounds of nitrogen per 1,000 square feet can help the turf grow out of lesions and thicken the stand. Slow-release nitrogen sources are often preferred for steady feeding and reduced burn risk, especially at the upper end of this rate range. Always calibrate your spreader and measure lawn area accurately to avoid over- or under-application.
Potassium is another nutrient to consider. Where soil tests show low or medium potassium levels, supplementing according to recommendations can strengthen cell walls and improve stress tolerance. Be cautious with high phosphorus applications unless a soil test indicates need, as excessive phosphorus can contribute to environmental issues and is not a direct solution to dollar spot.
Reworking your irrigation schedule can directly target one of the primary causes of dollar spots: extended leaf wetness. The goal is for turf to receive enough water to maintain healthy growth without keeping leaf surfaces wet overnight.
Start by determining how much water your sprinklers apply. Place several straight-sided containers, like tuna cans, in the lawn and run your system for 15 minutes. Measure the depth of water in each can and average it. If you find that 15 minutes equals 0.25 inches, for example, then a 60-minute run delivers about 1 inch of water. Use this information to schedule two deep, early-morning irrigations per week during dry spells, aiming for a total of about 1 to 1.5 inches of water per week including rainfall.
Set automatic systems so watering finishes between about 3 a.m. and 6 a.m. This timing allows dew to mix with irrigation, but still gives the sun and breeze several hours to dry the leaves by late morning. Avoid routine evening or nighttime watering during high-risk periods when temperatures and humidity are favorable for dollar spot.
To lower inoculum levels and improve drying around the turf base, focus on thatch, soil structure, and air movement. For lawns with more than 0.5 inch of thatch, consider light power raking or verticutting in early fall or spring when the turf can quickly recover. Avoid overly aggressive dethatching in hot or dry conditions because it can stress turf and temporarily increase vulnerability.
Core aeration, which removes plugs of soil and thatch, is one of the most practical tools for homeowners. Aerating once per year on compacted, high-traffic lawns or once every 1 to 2 years on less compacted turf helps improve infiltration, root depth, and oxygen levels, all of which make turf more resilient to disease. Leaving the cores to break down naturally or dragging them to crumble can also help dilute thatch with soil.
Where dollar spot is consistently worse in shaded or sheltered zones, evaluate opportunities to improve airflow. Pruning lower tree branches, selectively thinning densely planted beds, or opening narrow wind channels between structures can help these areas dry faster after dew or irrigation. These changes often provide benefits beyond disease control, including reduced moss and algae on hard surfaces.
For some lawns, especially high-value turf or properties with a chronic history of severe dollar spot, cultural changes alone may not be enough to prevent damage during peak pressure periods. In those cases, integrating fungicides as a preventive or early-curative tool can be justified.
If you choose to use fungicides, keep these principles in mind:
Always check that any product you choose is labeled for your grass species, for dollar spot, and for residential use if you are treating a home lawn. Wear appropriate protective equipment and follow all reentry intervals, especially where children or pets use the lawn regularly.
Many online resources mention that dollar spot is “caused by a fungus” and suggest a fungicide, but they often overlook critical diagnostic and management details. Avoid these common pitfalls to save time and money.
Skipping confirmation of the disease is a frequent error. Pale patches can also be drought stress, grub damage, or nutrient deficiency. If you treat drought or grubs with a fungicide, you will see no improvement and waste money. Always check for the distinctive leaf lesions and early-morning mycelium before concluding you have dollar spot.
Ignoring nitrogen status is another big oversight. Some guides treat fungicides as the main or only solution. In reality, if your lawn is underfed, dollar spot will keep returning as soon as fungicides wear off. Reviewing your annual nitrogen totals and using a soil test to guide potassium adjustments are key steps that many summaries simply skip.
Overwatering at the wrong time of day is also underemphasized. Guides may tell you “do not overwater,” but do not explain that 0.25 inches applied at 9 p.m. can be more damaging from a disease standpoint than 0.75 inches applied at 5 a.m. The combination of water amount, frequency, and timing is what matters for the causes of dollar spots that relate to leaf wetness.
Finally, failing to check for compaction and thatch leaves a big gap. If you never perform the simple screwdriver test for compaction or measure your thatch layer, you may be missing two of the most manageable underlying causes that make your lawn a permanent home for dollar spot fungi.
Turning this information into action is easier if you think seasonally. While climates differ, a general cool-season lawn plan might look like this:
Early spring (soil temps rising to 50-55°F): Perform a soil test if it has been more than 3 years. Sharpen mower blades. Assess thatch and compaction by cutting a small plug and performing a screwdriver test. Begin deep, infrequent irrigation only when needed.
Late spring (daily highs in 60s-70s°F): This is a high-risk dollar spot window. Ensure nitrogen applications are on track, typically 0.5 to 1.0 pound of nitrogen per 1,000 square feet depending on your annual plan. Check mowing height and adjust to at least 2.5 to 3 inches. Watch for persistent dew and spots, and perform early-morning mycelium checks. If your lawn has a history of severe dollar spot, consider a preventive fungicide during prolonged mild, humid stretches.
Summer: Focus on irrigation timing and depth. If weather is hot, avoid heavy nitrogen applications that could stress turf and favor other diseases. Monitor shaded or sheltered areas that stay moist. If dollar spot appears, reassess watering and traffic patterns.
Early fall: As temperatures cool back into the dollar spot range, apply another 0.5 to 1.0 pound of nitrogen per 1,000 square feet to support recovery and thickening. Fall is also a good time for core aeration and, if needed, moderate dethatching. Overseed thin areas with appropriate grass species and varieties with improved disease resistance.
Late fall: Apply a “winterizer” nitrogen application if recommended for your region, usually about 0.5 to 1.0 pound of nitrogen per 1,000 square feet. This supports root growth and early spring green-up, which in turn boosts turf vigor and disease resistance the following year.
By addressing the environmental, cultural, and biological causes of dollar spots across the year, you shift your lawn from a high-risk environment to one where dollar spot struggles to gain a foothold. Fungicides, if needed, then become an occasional tool instead of a constant crutch.
Dollar spot is not a mysterious random event. When you see small, straw-colored spots spreading across your lawn, you are looking at the visible outcome of specific causes: moderate temperatures, prolonged leaf wetness, low nitrogen, stress from mowing and compaction, and an active fungal population living in thatch and debris. Controlling the disease long term means systematically addressing these causes, not just spraying them away for a few weeks.
If you start by properly diagnosing the disease, then methodically improve fertility, mowing height, watering schedules, and soil structure, you can dramatically reduce the frequency and severity of outbreaks. For a deeper dive into building a stronger lawn overall, check out our guide on fall fertilizer timing to align nutrition with your grass’s natural growth cycles.
Look for fertilizers with a balanced analysis and at least 30 percent slow-release nitrogen, plan irrigation to deliver 1 to 1.5 inches of water per week in the early morning, and schedule annual aeration on compacted soils. These steps not only tackle the causes of dollar spots but also build a thicker, more resilient lawn that resists many other problems as well.
Dollar spots are caused by a fungal disease that thrives when nighttime temperatures are between about 60 and 85°F, humidity is high, and leaves stay wet for long periods from dew or evening irrigation. Low nitrogen fertility, mowing too short, and thick thatch all stress the grass and make it easier for the fungus to infect. Correcting these conditions is more effective than relying only on fungicides.
Look for many small, straw-colored spots 1 to 3 inches across and then pull a few blades from an affected area. If you see tan or bleached lesions with reddish-brown borders, often in an hourglass shape, that usually points to dollar spot. Check early in the morning for fine white, cottony growth in the dew on those spots, and if present, you can be confident it is dollar spot rather than drought or insect damage.
Start by improving lawn nutrition, especially nitrogen, with 0.5 to 0.75 pounds of nitrogen per 1,000 square feet during active growth if the turf is pale and thin. Adjust irrigation so you water deeply in the early morning and the grass dries by midmorning, and raise mowing height to at least 2.5 to 3 inches on cool-season lawns. Core aeration and light thatch reduction help the lawn dry faster and reduce the fungus’s habitat, so outbreaks become less frequent and severe.
Dollar spot is most active when days are mild and nights are cool and humid, usually in late spring and again in early fall for cool-season lawns. The best time to act is at the first sign of small bleached spots, combined with weather forecasts showing several days of cool, dewy mornings ahead. Cultural fixes like adjusting nitrogen and watering should be started immediately, and if you use fungicides, apply them early in the outbreak for 14 to 21 days of protection.
Yes, you should still water, but adjust how and when you do it. Water deeply and infrequently so the soil is moistened to 4 to 6 inches, rather than applying frequent shallow irrigation that only wets the foliage. Schedule watering to finish between about 3 a.m. and 6 a.m., so leaves dry by late morning and you minimize the long periods of leaf wetness that drive dollar spot infections.
Once you correct the underlying causes and, if needed, protect the lawn with a fungicide, new spots usually stop forming within 7 to 14 days. The bleached leaves will not turn green again, so recovery depends on how quickly the grass can grow new foliage, which typically takes several weeks under good growing conditions. In severe cases with thinning, you may need to overseed in early fall to restore density, and full visual recovery can take a month or more.
Common questions about this topic
Dollar spots are caused by a fungal disease that thrives when nighttime temperatures are between about 60 and 85°F, humidity is high, and leaves stay wet for long periods from dew or evening irrigation. Low nitrogen fertility, mowing too short, and thick thatch all stress the grass and make it easier for the fungus to infect. Correcting these conditions is more effective than relying only on fungicides.
Look for many small, straw-colored spots 1 to 3 inches across and then pull a few blades from an affected area. If you see tan or bleached lesions with reddish-brown borders, often in an hourglass shape, that usually points to dollar spot. Check early in the morning for fine white, cottony growth in the dew on those spots, and if present, you can be confident it is dollar spot rather than drought or insect damage.
Start by improving lawn nutrition, especially nitrogen, with 0.5 to 0.75 pounds of nitrogen per 1,000 square feet during active growth if the turf is pale and thin. Adjust irrigation so you water deeply in the early morning and the grass dries by midmorning, and raise mowing height to at least 2.5 to 3 inches on cool-season lawns. Core aeration and light thatch reduction help the lawn dry faster and reduce the fungus’s habitat, so outbreaks become less frequent and severe.
Dollar spot is most active when days are mild and nights are cool and humid, usually in late spring and again in early fall for cool-season lawns. The best time to act is at the first sign of small bleached spots, combined with weather forecasts showing several days of cool, dewy mornings ahead. Cultural fixes like adjusting nitrogen and watering should be started immediately, and if you use fungicides, apply them early in the outbreak for 14 to 21 days of protection.
Yes, you should still water, but adjust how and when you do it. Water deeply and infrequently so the soil is moistened to 4 to 6 inches, rather than applying frequent shallow irrigation that only wets the foliage. Schedule watering to finish between about 3 a.m. and 6 a.m., so leaves dry by late morning and you minimize the long periods of leaf wetness that drive dollar spot infections.
Once you correct the underlying causes and, if needed, protect the lawn with a fungicide, new spots usually stop forming within 7 to 14 days. The bleached leaves will not turn green again, so recovery depends on how quickly the grass can grow new foliage, which typically takes several weeks under good growing conditions. In severe cases with thinning, you may need to overseed in early fall to restore density, and full visual recovery can take a month or more.
