Fertilizing
Seasonal care guides delivered to your inbox
Loading product recommendations...
How to Read Fertilizer Numbers
12 sections • 0% read
Brown or weak lawns often trace back to one thing: the wrong fertilizer numbers for your soil and grass. If you can read fertilizer numbers correctly, you can control growth, color, and recovery instead of guessing with every bag you buy.
This guide explains how to read fertilizer numbers, what N-P-K really means, and how to match those numbers to your lawn or garden. We will cover what the three fertilizer numbers mean, how to choose the right analysis for your situation, and how much and how often to apply it without wasting money or burning the turf. If you are also comparing product types, see related topics like Best Fertilizers for Lawns, Organic vs Synthetic Fertilizers, How to Test Your Lawn's Soil, How to Improve Soil pH for Grass, and Composting for a Healthier Lawn.
Fertilizer numbers are always listed as N-P-K, which means nitrogen, phosphorus, and potassium. A bag labeled 24-0-6 contains 24 percent nitrogen for green growth, 0 percent phosphorus for roots, and 6 percent potassium for stress tolerance. If the first number is much higher than the others, the product is focused on leaf and blade growth, which is ideal for established lawns but not for new seed.
To confirm a fertilizer fits your needs, compare the numbers to your goal: for thick green turf, look for a higher first number such as 20-0-5; for new lawns or seeding, choose something with a higher middle number such as 18-24-12; for winter hardiness, favor a stronger third number like 22-0-14. Avoid applying more than 1 pound of nitrogen per 1,000 square feet in a single application, and wait at least 6 to 8 weeks between full-strength feedings. Most lawns show noticeable color improvement within 7 to 10 days with quick-release nitrogen and within 2 to 3 weeks with slow-release products.
When you pick up a fertilizer bag and see something like 24-0-6 or 10-10-10 on the front, those three numbers are the fertilizer analysis. In simple terms, they tell you which nutrients are in the product and how strong they are. Learning to read these fertilizer numbers lets you predict how the product will act on your lawn or plants before you ever spread it.
By law, every fertilizer sold in the United States must include a guaranteed analysis. You usually find it on the front of the bag or bottle as three bold numbers separated by dashes, and again in more detail in a box on the back or side label. This guarantee is your roadmap for nutrient content and is the key to comparing products accurately instead of just trusting brand names or marketing terms like “green-up” or “winterizer.”
The three fertilizer numbers always appear in the same order: N-P-K.
Nitrogen (N) - first number supports leaf and blade growth, deep green color, and overall lawn density. High nitrogen fertilizers push top growth, thicken turf, and improve visual appeal. If your lawn looks pale, yellowish, or thin, a lack of nitrogen is often the primary issue.
Phosphorus (P) - second number supports root development, seedling establishment, and, for some plants, flowering. New lawns from seed or sod, as well as recently transplanted shrubs and perennials, respond well to a moderate bump in phosphorus when soil tests indicate it is low.
Potassium (K) - third number is critical for stress tolerance, disease resistance, and cold and drought hardiness. Potassium is like the immune support system of the plant. Lawns going into summer heat or winter cold often benefit from adequate potassium so they can handle stress without thinning out.
A helpful analogy is to think of N-P-K as the protein, vitamins, and minerals for your lawn. Nitrogen is the main fuel for visible growth, phosphorus is the rooting and establishment support, and potassium keeps the whole system tough and resilient.
Each fertilizer number is the percentage by weight of that nutrient in the product. That means a 24-0-6 fertilizer is 24 percent nitrogen, 0 percent phosphorus, and 6 percent potassium by weight. The rest of the bag is filler, carrier materials, and sometimes secondary or micronutrients.
On the detailed label, phosphorus and potassium are listed in oxide forms, written as P₂O₅ for phosphate and K₂O for potash. This is a historical labeling convention used for regulation. You do not need to convert these for normal lawn care. Just understand that the second and third numbers refer to these oxide forms, and they are consistent from product to product, which lets you compare them safely.
Here is a quick example: In a 50 pound bag of 24-0-6 fertilizer:
That 50 pound bag physically contains 12 pounds of nitrogen and 3 pounds of potash that will be spread across the lawn. Understanding this helps you calculate application rates, like not exceeding 1 pound of nitrogen per 1,000 square feet at one time.
The N-P-K numbers cover the primary macronutrients, the three elements lawns and plants use in the greatest amounts. There are also secondary nutrients and micronutrients that matter, especially if your lawn has chronic color or growth problems.
Secondary nutrients include calcium, magnesium, and sulfur. These often appear in the guaranteed analysis box below the N-P-K line. Calcium affects soil structure and root health, magnesium is part of chlorophyll and affects color, and sulfur can acidify soil slightly and help with greening.
Micronutrients include iron, manganese, zinc, copper, boron, and others. Lawns with iron deficiency, for example, often look yellow-green even when nitrogen is adequate. Some “iron plus” or “micro-nutrient blend” fertilizers add small amounts of these elements to fine tune color and performance, especially on high pH soils.
When you read fertilizer numbers, start with N-P-K, then scan the secondary and micronutrient section if you are trying to correct a specific issue such as iron chlorosis or a known magnesium deficiency from a soil test.
Instead of treating each bag like a mystery, you can use a simple three step process to read any fertilizer numbers and decide if the product fits your lawn or garden goals. This process works for granular bags and liquid concentrates.
On granular lawn fertilizers, the N-P-K numbers are almost always printed on the front in large type, for example 29-0-4 or 32-0-10. On the back or side panel, you will see a “Guaranteed Analysis” box that repeats those three numbers and often expands with secondary nutrients.
On liquid fertilizers, look near the product name on the front or top section of the label. It might read 12-4-8 or 10-0-0. Below that, a table or box will specify nutrient percentages and sometimes whether they are quick release or slow release forms of nitrogen.
One rule is fixed: the order is always N - P - K. If you see three numbers, no matter the product type, they represent nitrogen, then phosphorus, then potassium. Once you can spot that pattern quickly, you are ready to decode what the ratio tells you.
The shape of the N-P-K ratio tells you how the fertilizer will behave.
If the first number is highest, such as 24-0-6 or 30-0-4, the product is nitrogen heavy and designed to push leafy growth and green color. This is ideal for established lawns and foliage plants where you are not trying to encourage blooms or establish new roots.
If the middle number is relatively high, such as 18-24-12 or 10-20-10, the product emphasizes phosphorus for root growth, seeding, and establishment. Starter fertilizers for new lawns almost always have a higher middle number, assuming local regulations allow phosphorus use.
If the last number is high, such as 0-0-60 or 22-0-14, the product is high in potassium, often marketed as “winterizer” or “stress blend.” These are used where soil tests or turf performance indicate a need for stronger stress tolerance as the lawn enters summer or winter.
Common examples and uses include:
By comparing these ratios, you can see whether a product is aggressive on top growth, root-building, or stress protection.
Next, connect what the numbers say to what your lawn or garden actually needs. This depends on grass type, soil test results, season, and whether you are working with an established lawn, a new seeding, or ornamental beds.
If your established lawn is thin and pale but otherwise healthy, a nitrogen forward fertilizer such as 24-0-6 applied at 0.5 to 1.0 pound of nitrogen per 1,000 square feet is often appropriate. For a typical 50 pound bag at 24 percent nitrogen, that bag will cover roughly 12,000 to 24,000 square feet depending on the rate you choose.
If you are seeding a new lawn, look for a starter formula like 18-24-12, but only use phosphorus where it is legal and your soil test indicates need. Many states restrict phosphorus on established turf unless a soil test shows low levels. If phosphorus is restricted, choose a starter with low or zero middle number and focus on proper watering and soil preparation instead.
If your area has hot summers or cold winters and your soil test shows low potassium, you might use a product such as 22-0-14 in late summer or early fall. This supports stress tolerance as the grass prepares for seasonal extremes.
For flowers and vegetables, a more balanced ratio like 10-10-10 or a plant specific analysis (for example, tomato blends with slightly higher potassium) is common. Always cross-check with a soil test when possible to avoid building up excess nutrients, especially phosphorus.
Once you can read the fertilizer numbers and know which ratio you want, the next step is getting the rate right. Most lawn problems from fertilizer are caused not by choosing the wrong analysis, but by applying too much nitrogen at once or reapplying too soon.
A common recommendation for cool season lawns is to apply no more than 0.75 to 1.0 pound of nitrogen per 1,000 square feet in a single application during the growing season. Warm season grasses often use similar or slightly lower single application rates depending on the specific species and region.
To calculate how much product to apply, you divide the desired nitrogen rate per 1,000 square feet by the nitrogen percentage (as a decimal). For example, if you want 1.0 pound of nitrogen per 1,000 square feet using a 24-0-6 fertilizer:
If the bag weighs 50 pounds, then 50 ÷ 4.2 ≈ 12, which means one bag covers about 12,000 square feet at that rate.
Space applications at least 6 to 8 weeks apart for full rate granular fertilizers unless the label specifies a different interval. Applying too frequently or at higher than labeled rates is what typically leads to fertilizer burn and excessive top growth that the roots cannot support.
The fertilizer numbers also interact with timing. A high nitrogen fertilizer at a strong rate lasts longer in the soil, while lighter doses or lower N percentages provide a gentler, shorter effect. Season and grass type decide how often you should feed.
For cool season grasses such as Kentucky bluegrass, fescue, and ryegrass, the main feeding window is fall, roughly September through early November in many temperate regions, when soil temperatures are cool but grass is still actively growing. A typical program might include 2 to 3 applications of 0.75 to 1.0 pound N per 1,000 square feet spaced 6 to 8 weeks apart in fall, using something like 24-0-6 or 29-0-4.
For warm season grasses such as Bermuda, zoysia, and St. Augustine, the primary fertilization period is late spring through summer once soil temperatures are consistently above about 65 degrees Fahrenheit. Early spring applications on dormant warm season turf usually provide little benefit and can encourage weeds more than grass.
Starter fertilizers like 18-24-12 are applied once at seeding or sodding, usually at a lighter nitrogen rate of about 0.5 pound N per 1,000 square feet. After establishment, you switch to a regular maintenance analysis based on your soil test and grass type.
Many basic articles on how to read fertilizer numbers stop at “N is for leaves, P is for roots, K is for stress,” but there are some practical points they often skip that matter for real lawns.
One missed step is confirmation with a soil test. If your phosphorus level is already high, adding a fertilizer with a high middle number does not improve rooting and can contribute to runoff issues. Before using high P or K products, test your soil at least every 3 to 4 years. This is outlined in more detail in How to Test Your Lawn's Soil.
Another gap is matching analysis to your grass type, not just the season. For example, a cool season blend like 32-0-4 marketed for spring green-up can be too aggressive for certain fine fescue lawns which prefer lower nitrogen. If you see rapid top growth that outpaces your mowing schedule or a flush of disease after fertilizing, you likely chose too high a nitrogen number or applied too much at once. Confirm by reviewing the bag rate and your spreader setting. Next time, step down to a product with a lower first number or reduce the application rate.
Safety intervals are also under-reported. If you suspect you over-applied, check for signs of burn such as brown streaks or patches appearing within 24 to 48 hours, especially along overlap zones of your spreader path. If detected early and the product is water soluble, deep watering within that 48 hour window can sometimes dilute the salts enough to reduce damage, though it will not fully reverse severe burn.
When you stand in the fertilizer aisle, you can make a fast, informed decision by following a simple workflow that uses the fertilizer numbers rather than marketing claims. First, identify your situation: established lawn, new seeding, or garden plants. Second, review your most recent soil test to see if phosphorus or potassium are low, adequate, or high. If you do not have a test and are planning more than one season of improvements, prioritize getting one done.
Third, pick an N-P-K ratio that matches your goal. For most established lawns with no extreme soil deficiencies, a nitrogen forward, low or zero phosphorus product such as 24-0-6 is appropriate, especially where phosphorus use is regulated. For seeding or sodding, use a starter blend with higher phosphorus only if your soil test indicates low P and local rules allow it. For stress tolerance going into summer or winter, consider an analysis with a somewhat higher third number if your soil test shows low potassium.
Fourth, calculate the rate. Keep each application at or below about 1 pound of nitrogen per 1,000 square feet unless a local extension recommendation and label rate suggest slightly different numbers for your grass type. Space applications by at least 6 to 8 weeks for full rate products, and adjust based on how your turf responds.
Brown or weak lawns often trace back to one thing: the wrong fertilizer numbers for your soil and grass. If you can read fertilizer numbers correctly, you can control growth, color, and recovery instead of guessing with every bag you buy.
This guide explains how to read fertilizer numbers, what N-P-K really means, and how to match those numbers to your lawn or garden. We will cover what the three fertilizer numbers mean, how to choose the right analysis for your situation, and how much and how often to apply it without wasting money or burning the turf. If you are also comparing product types, see related topics like Best Fertilizers for Lawns, Organic vs Synthetic Fertilizers, How to Test Your Lawn's Soil, How to Improve Soil pH for Grass, and Composting for a Healthier Lawn.
Fertilizer numbers are always listed as N-P-K, which means nitrogen, phosphorus, and potassium. A bag labeled 24-0-6 contains 24 percent nitrogen for green growth, 0 percent phosphorus for roots, and 6 percent potassium for stress tolerance. If the first number is much higher than the others, the product is focused on leaf and blade growth, which is ideal for established lawns but not for new seed.
To confirm a fertilizer fits your needs, compare the numbers to your goal: for thick green turf, look for a higher first number such as 20-0-5; for new lawns or seeding, choose something with a higher middle number such as 18-24-12; for winter hardiness, favor a stronger third number like 22-0-14. Avoid applying more than 1 pound of nitrogen per 1,000 square feet in a single application, and wait at least 6 to 8 weeks between full-strength feedings. Most lawns show noticeable color improvement within 7 to 10 days with quick-release nitrogen and within 2 to 3 weeks with slow-release products.
When you pick up a fertilizer bag and see something like 24-0-6 or 10-10-10 on the front, those three numbers are the fertilizer analysis. In simple terms, they tell you which nutrients are in the product and how strong they are. Learning to read these fertilizer numbers lets you predict how the product will act on your lawn or plants before you ever spread it.
By law, every fertilizer sold in the United States must include a guaranteed analysis. You usually find it on the front of the bag or bottle as three bold numbers separated by dashes, and again in more detail in a box on the back or side label. This guarantee is your roadmap for nutrient content and is the key to comparing products accurately instead of just trusting brand names or marketing terms like “green-up” or “winterizer.”
The three fertilizer numbers always appear in the same order: N-P-K.
Nitrogen (N) - first number supports leaf and blade growth, deep green color, and overall lawn density. High nitrogen fertilizers push top growth, thicken turf, and improve visual appeal. If your lawn looks pale, yellowish, or thin, a lack of nitrogen is often the primary issue.
Phosphorus (P) - second number supports root development, seedling establishment, and, for some plants, flowering. New lawns from seed or sod, as well as recently transplanted shrubs and perennials, respond well to a moderate bump in phosphorus when soil tests indicate it is low.
Potassium (K) - third number is critical for stress tolerance, disease resistance, and cold and drought hardiness. Potassium is like the immune support system of the plant. Lawns going into summer heat or winter cold often benefit from adequate potassium so they can handle stress without thinning out.
A helpful analogy is to think of N-P-K as the protein, vitamins, and minerals for your lawn. Nitrogen is the main fuel for visible growth, phosphorus is the rooting and establishment support, and potassium keeps the whole system tough and resilient.
Each fertilizer number is the percentage by weight of that nutrient in the product. That means a 24-0-6 fertilizer is 24 percent nitrogen, 0 percent phosphorus, and 6 percent potassium by weight. The rest of the bag is filler, carrier materials, and sometimes secondary or micronutrients.
On the detailed label, phosphorus and potassium are listed in oxide forms, written as P₂O₅ for phosphate and K₂O for potash. This is a historical labeling convention used for regulation. You do not need to convert these for normal lawn care. Just understand that the second and third numbers refer to these oxide forms, and they are consistent from product to product, which lets you compare them safely.
Here is a quick example: In a 50 pound bag of 24-0-6 fertilizer:
That 50 pound bag physically contains 12 pounds of nitrogen and 3 pounds of potash that will be spread across the lawn. Understanding this helps you calculate application rates, like not exceeding 1 pound of nitrogen per 1,000 square feet at one time.
The N-P-K numbers cover the primary macronutrients, the three elements lawns and plants use in the greatest amounts. There are also secondary nutrients and micronutrients that matter, especially if your lawn has chronic color or growth problems.
Secondary nutrients include calcium, magnesium, and sulfur. These often appear in the guaranteed analysis box below the N-P-K line. Calcium affects soil structure and root health, magnesium is part of chlorophyll and affects color, and sulfur can acidify soil slightly and help with greening.
Micronutrients include iron, manganese, zinc, copper, boron, and others. Lawns with iron deficiency, for example, often look yellow-green even when nitrogen is adequate. Some “iron plus” or “micro-nutrient blend” fertilizers add small amounts of these elements to fine tune color and performance, especially on high pH soils.
When you read fertilizer numbers, start with N-P-K, then scan the secondary and micronutrient section if you are trying to correct a specific issue such as iron chlorosis or a known magnesium deficiency from a soil test.
Instead of treating each bag like a mystery, you can use a simple three step process to read any fertilizer numbers and decide if the product fits your lawn or garden goals. This process works for granular bags and liquid concentrates.
On granular lawn fertilizers, the N-P-K numbers are almost always printed on the front in large type, for example 29-0-4 or 32-0-10. On the back or side panel, you will see a “Guaranteed Analysis” box that repeats those three numbers and often expands with secondary nutrients.
On liquid fertilizers, look near the product name on the front or top section of the label. It might read 12-4-8 or 10-0-0. Below that, a table or box will specify nutrient percentages and sometimes whether they are quick release or slow release forms of nitrogen.
One rule is fixed: the order is always N - P - K. If you see three numbers, no matter the product type, they represent nitrogen, then phosphorus, then potassium. Once you can spot that pattern quickly, you are ready to decode what the ratio tells you.
The shape of the N-P-K ratio tells you how the fertilizer will behave.
If the first number is highest, such as 24-0-6 or 30-0-4, the product is nitrogen heavy and designed to push leafy growth and green color. This is ideal for established lawns and foliage plants where you are not trying to encourage blooms or establish new roots.
If the middle number is relatively high, such as 18-24-12 or 10-20-10, the product emphasizes phosphorus for root growth, seeding, and establishment. Starter fertilizers for new lawns almost always have a higher middle number, assuming local regulations allow phosphorus use.
If the last number is high, such as 0-0-60 or 22-0-14, the product is high in potassium, often marketed as “winterizer” or “stress blend.” These are used where soil tests or turf performance indicate a need for stronger stress tolerance as the lawn enters summer or winter.
Common examples and uses include:
By comparing these ratios, you can see whether a product is aggressive on top growth, root-building, or stress protection.
Next, connect what the numbers say to what your lawn or garden actually needs. This depends on grass type, soil test results, season, and whether you are working with an established lawn, a new seeding, or ornamental beds.
If your established lawn is thin and pale but otherwise healthy, a nitrogen forward fertilizer such as 24-0-6 applied at 0.5 to 1.0 pound of nitrogen per 1,000 square feet is often appropriate. For a typical 50 pound bag at 24 percent nitrogen, that bag will cover roughly 12,000 to 24,000 square feet depending on the rate you choose.
If you are seeding a new lawn, look for a starter formula like 18-24-12, but only use phosphorus where it is legal and your soil test indicates need. Many states restrict phosphorus on established turf unless a soil test shows low levels. If phosphorus is restricted, choose a starter with low or zero middle number and focus on proper watering and soil preparation instead.
If your area has hot summers or cold winters and your soil test shows low potassium, you might use a product such as 22-0-14 in late summer or early fall. This supports stress tolerance as the grass prepares for seasonal extremes.
For flowers and vegetables, a more balanced ratio like 10-10-10 or a plant specific analysis (for example, tomato blends with slightly higher potassium) is common. Always cross-check with a soil test when possible to avoid building up excess nutrients, especially phosphorus.
Once you can read the fertilizer numbers and know which ratio you want, the next step is getting the rate right. Most lawn problems from fertilizer are caused not by choosing the wrong analysis, but by applying too much nitrogen at once or reapplying too soon.
A common recommendation for cool season lawns is to apply no more than 0.75 to 1.0 pound of nitrogen per 1,000 square feet in a single application during the growing season. Warm season grasses often use similar or slightly lower single application rates depending on the specific species and region.
To calculate how much product to apply, you divide the desired nitrogen rate per 1,000 square feet by the nitrogen percentage (as a decimal). For example, if you want 1.0 pound of nitrogen per 1,000 square feet using a 24-0-6 fertilizer:
If the bag weighs 50 pounds, then 50 ÷ 4.2 ≈ 12, which means one bag covers about 12,000 square feet at that rate.
Space applications at least 6 to 8 weeks apart for full rate granular fertilizers unless the label specifies a different interval. Applying too frequently or at higher than labeled rates is what typically leads to fertilizer burn and excessive top growth that the roots cannot support.
The fertilizer numbers also interact with timing. A high nitrogen fertilizer at a strong rate lasts longer in the soil, while lighter doses or lower N percentages provide a gentler, shorter effect. Season and grass type decide how often you should feed.
For cool season grasses such as Kentucky bluegrass, fescue, and ryegrass, the main feeding window is fall, roughly September through early November in many temperate regions, when soil temperatures are cool but grass is still actively growing. A typical program might include 2 to 3 applications of 0.75 to 1.0 pound N per 1,000 square feet spaced 6 to 8 weeks apart in fall, using something like 24-0-6 or 29-0-4.
For warm season grasses such as Bermuda, zoysia, and St. Augustine, the primary fertilization period is late spring through summer once soil temperatures are consistently above about 65 degrees Fahrenheit. Early spring applications on dormant warm season turf usually provide little benefit and can encourage weeds more than grass.
Starter fertilizers like 18-24-12 are applied once at seeding or sodding, usually at a lighter nitrogen rate of about 0.5 pound N per 1,000 square feet. After establishment, you switch to a regular maintenance analysis based on your soil test and grass type.
Many basic articles on how to read fertilizer numbers stop at “N is for leaves, P is for roots, K is for stress,” but there are some practical points they often skip that matter for real lawns.
One missed step is confirmation with a soil test. If your phosphorus level is already high, adding a fertilizer with a high middle number does not improve rooting and can contribute to runoff issues. Before using high P or K products, test your soil at least every 3 to 4 years. This is outlined in more detail in How to Test Your Lawn's Soil.
Another gap is matching analysis to your grass type, not just the season. For example, a cool season blend like 32-0-4 marketed for spring green-up can be too aggressive for certain fine fescue lawns which prefer lower nitrogen. If you see rapid top growth that outpaces your mowing schedule or a flush of disease after fertilizing, you likely chose too high a nitrogen number or applied too much at once. Confirm by reviewing the bag rate and your spreader setting. Next time, step down to a product with a lower first number or reduce the application rate.
Safety intervals are also under-reported. If you suspect you over-applied, check for signs of burn such as brown streaks or patches appearing within 24 to 48 hours, especially along overlap zones of your spreader path. If detected early and the product is water soluble, deep watering within that 48 hour window can sometimes dilute the salts enough to reduce damage, though it will not fully reverse severe burn.
When you stand in the fertilizer aisle, you can make a fast, informed decision by following a simple workflow that uses the fertilizer numbers rather than marketing claims. First, identify your situation: established lawn, new seeding, or garden plants. Second, review your most recent soil test to see if phosphorus or potassium are low, adequate, or high. If you do not have a test and are planning more than one season of improvements, prioritize getting one done.
Third, pick an N-P-K ratio that matches your goal. For most established lawns with no extreme soil deficiencies, a nitrogen forward, low or zero phosphorus product such as 24-0-6 is appropriate, especially where phosphorus use is regulated. For seeding or sodding, use a starter blend with higher phosphorus only if your soil test indicates low P and local rules allow it. For stress tolerance going into summer or winter, consider an analysis with a somewhat higher third number if your soil test shows low potassium.
Fourth, calculate the rate. Keep each application at or below about 1 pound of nitrogen per 1,000 square feet unless a local extension recommendation and label rate suggest slightly different numbers for your grass type. Space applications by at least 6 to 8 weeks for full rate products, and adjust based on how your turf responds.
The three numbers on a fertilizer bag are always in the order N-P-K, which stands for nitrogen, phosphorus, and potassium. Each number shows the percentage by weight of that nutrient in the product. For example, a 24-0-6 fertilizer is 24% nitrogen, 0% phosphorus, and 6% potassium, with the rest made up of filler and possibly secondary or micronutrients. These numbers let you compare how strong different fertilizers are and how they will affect your lawn.
For thick, green turf, look for a fertilizer with a higher first number, such as 20-0-5 or similar, because nitrogen is what drives color and leaf growth. High-nitrogen formulas help thicken the lawn and improve visual appeal when the grass looks pale or thin. Just be sure not to exceed 1 pound of nitrogen per 1,000 square feet in a single application. Allow 6 to 8 weeks between full-strength feedings to avoid burning the turf.
New lawns from seed or sod benefit from a fertilizer with more emphasis on the middle number, phosphorus, to support strong root development. A typical analysis for new lawns would be something like 18-24-12, which gives a noticeable boost to phosphorus while still providing nitrogen and potassium. This helps seedlings establish faster and creates a stronger root system. Always confirm with a soil test if possible to avoid adding phosphorus when it’s already high.
To improve stress tolerance going into heat or cold, choose a fertilizer with a stronger third number, which is potassium. An analysis like 22-0-14 supplies enough nitrogen for growth while boosting potassium for disease resistance and cold and drought hardiness. Potassium acts like an immune support system, helping the lawn handle stress without thinning out. Using this type of product before tough seasons can improve survival and appearance.
Multiply the first fertilizer number (nitrogen percentage) by the bag weight to find pounds of nitrogen. For example, a 50-pound bag of 24-0-6 contains 0.24 × 50 = 12 pounds of actual nitrogen. To stay within 1 pound of nitrogen per 1,000 square feet, you would spread that 50-pound bag over about 12,000 square feet. This simple calculation helps avoid over-applying and burning your grass.
The main fertilizer numbers (N-P-K) are the primary macronutrients that lawns use in the largest amounts. Below them, the label may list secondary nutrients like calcium, magnesium, and sulfur, along with micronutrients such as iron, manganese, and zinc. These extras help fine-tune color, root health, and stress response, especially if a soil test shows specific deficiencies. When choosing a product, focus on N-P-K first, then look at these added nutrients if you’re targeting a particular problem like yellowing from iron deficiency.
Common questions about this topic
The three numbers on a fertilizer bag are always in the order N-P-K, which stands for nitrogen, phosphorus, and potassium. Each number shows the percentage by weight of that nutrient in the product. For example, a 24-0-6 fertilizer is 24% nitrogen, 0% phosphorus, and 6% potassium, with the rest made up of filler and possibly secondary or micronutrients. These numbers let you compare how strong different fertilizers are and how they will affect your lawn.
For thick, green turf, look for a fertilizer with a higher first number, such as 20-0-5 or similar, because nitrogen is what drives color and leaf growth. High-nitrogen formulas help thicken the lawn and improve visual appeal when the grass looks pale or thin. Just be sure not to exceed 1 pound of nitrogen per 1,000 square feet in a single application. Allow 6 to 8 weeks between full-strength feedings to avoid burning the turf.
New lawns from seed or sod benefit from a fertilizer with more emphasis on the middle number, phosphorus, to support strong root development. A typical analysis for new lawns would be something like 18-24-12, which gives a noticeable boost to phosphorus while still providing nitrogen and potassium. This helps seedlings establish faster and creates a stronger root system. Always confirm with a soil test if possible to avoid adding phosphorus when it’s already high.
To improve stress tolerance going into heat or cold, choose a fertilizer with a stronger third number, which is potassium. An analysis like 22-0-14 supplies enough nitrogen for growth while boosting potassium for disease resistance and cold and drought hardiness. Potassium acts like an immune support system, helping the lawn handle stress without thinning out. Using this type of product before tough seasons can improve survival and appearance.
Multiply the first fertilizer number (nitrogen percentage) by the bag weight to find pounds of nitrogen. For example, a 50-pound bag of 24-0-6 contains 0.24 × 50 = 12 pounds of actual nitrogen. To stay within 1 pound of nitrogen per 1,000 square feet, you would spread that 50-pound bag over about 12,000 square feet. This simple calculation helps avoid over-applying and burning your grass.
The main fertilizer numbers (N-P-K) are the primary macronutrients that lawns use in the largest amounts. Below them, the label may list secondary nutrients like calcium, magnesium, and sulfur, along with micronutrients such as iron, manganese, and zinc. These extras help fine-tune color, root health, and stress response, especially if a soil test shows specific deficiencies. When choosing a product, focus on N-P-K first, then look at these added nutrients if you’re targeting a particular problem like yellowing from iron deficiency.
