How Much Fertilizer for Your Lawn: A Comprehensive Guide

Do you have a lawn or do you plan to have a garden? Because, just like kids need nutrients to grow, so does your lawn. Your plants or grass cannot get all the nutrients from the soil because the soil needs time to regenerate.

This is why you need fertilizer to nourish your lawn. If you don’t know how much fertilizer for the lawn, then you get lawn burn where a few spots look dead in the rest of the lawn.

When it comes to determining the amount of fertilizer for your lawn, there is confusion about what to use, depending on your lawn's size and your specific needs.

Why Proper Fertilizer Amounts Matter

There are essential nutrients that your plants or grass need in order for optimum growth, and the soil needs time to regenerate. If the soil lacks nutrients, then your plants may die or the grass may grow unevenly. This is why soil testing for lawns is important.

To check lawn health, simply get a small soil testing kit or send samples to the lab. You will know more about soil and whether or not your soil can utilize the lawn fertilizer benefits.

Signs of Over-Fertilizing Lawn 

If there is no soil testing for the lawn and adding fertilizer, you end up over-fertilizing lawn, then you will get lawn burn. When you water your lawn manually or by smart Aiper’s IrriSense, you will end up polluting waterways because of nutrient runoff, where excess nutrients end up in waterways. This harms the environment, and the cause is over-fertilizing the lawn.

Signs of Under-Fertilizing Lawn

If you under-fertilize, you will get yellowing of the grass, weak growth, and may experience damage due to pests. The benefits of lawn fertilizers are that you don’t have to deal with all this separately.

If you do soil testing for the lawn, you know that your soil even needs fertilizer. And you know what is essential for supporting soil health. If you want to proceed with lawn, then soil testing for your lawn is crucial.

Understanding Fertilizer Basics

Fertilizer consists of important nutrients, i.e., nitrogen, phosphorus, and potassium, referred to as NPK. Always look at the N-P-K ratio. If the ratio is 20-0-10, it means 20% nitrogen, 0% phosphorus, 10% potassium. But what should be the ideal NPK ratio for your lawn? This is why soil testing is essential. But why only three nutrients?

Nitrogen is responsible for the growth of leaves and the greenness of a plant or grass. It is typically recommended to apply 1-2 pounds of nitrogen per 1,000 sq. ft. per application.. Phosphorus is responsible for strong root development, flower formation on plants, and fruit production. It assists plants in energy transfer and promotes the development of strong roots. Potassium is essential for overall health and helps build resilience. It helps regulate water uptake and growth of larger fruits, vibrant flowers. 

Different Types of Fertilizer

You need different fertilizers based on your needs.

1. Granular: Easy to use and slow in releasing nutrients. An ideal choice for steady feeding of the lawn. An application can last 4-6 weeks. For example, Scotts Turf Builder.
2. Liquid: They release nutrients quickly. They are better for quick fixes. But you might need frequent applications. You might also need a calibrated backpack sprayer.
3. Organic: This fertilizer is made from organic waste. It could be meat waste, food waste, or animal manure, making them environmentally friendly. They have lower nutrient concentration. For example, Milorganite.
4. Synthetic: This fertilizer is manufactured in a laboratory where two naturally occurring compounds do not form bonds with each other. They have high nutrient concentration and give quick results.

How to Calculate the Right Amount of Fertilizer

Always measure how much and what kind of fertilizer you need for your lawn. If you get the wrong amount, then you might end up over- or under-fertilizing, which will give you more worries because you get yellowish grass, burnt grass, or weak plants. For a beautiful lawn, what’s the right amount of fertilizer?

Step 1. Measure Your Lawn Size

Measure your lawn size in square footage. Exclude non-turf areas like your driveways or patios. You can also divide sections in your lawns and add each area up for complex lawn areas.

• To calculate rectangular lawn area: Area = Length × Width
• To calculate triangular lawn area: Area = (Base × Height) ÷ 2

For example, a front lawn measuring 50 ft × 100 ft equals 5,000 sq. ft.

Back lawn of 200 ft × 100 ft = 20,000 sq. ft.

Total lawn area = 25,000 sq. ft.

Step 2. Check Fertilizer Recommendation

Based on the soil type, use different kinds of fertilizers. For example, 1-2 pounds of nitrogen in fertilizer is recommended for lawn care per 1000 sq. ft., but only in cool-season grasses. For warm-seasoned grasses, then 0.5-1 pound per 1000 sq. ft.

To determine the amount of nitrogen, check the NPK ratio, which is 20-0-10, respectively. This means that nitrogen makes up 20% of the total. 

Step 3. Do the Math

To precisely measure fertilizer amount for your lawn:

(Recommended pounds of nitrogen per 1,000 sq. ft.÷ Nitrogen percentage) × Lawn size in thousands of sq. ft. = Total pounds of fertilizer.

For example, for a 25,000 sq. ft. lawn with a recommendation of 1 pound of nitrogen per 1,000 sq. ft. using a 20% nitrogen fertilizer:

(1 ÷ 20) × 25 = 5 pounds fertilizer per 1,000 sq. ft. × 25 = 125 pounds fertilizer for total lawn area.

Step 4. Adjust for Fertilizer Type

You may need different amounts of nitrogen, depending on the soil and your lawn. If you are using soluble inorganic fertilizers ,then use 1 pound of nitrogen per 1,000 sq. ft. per application.

If you have slow-release fertilizer like granular fertilizer, then you can have a higher concentration because nutrients are released gradually.

When and How to Apply Fertilizer

You should not just sprinkle fertilizer all over the lawn. Actually, you can get problems with that. Advice is to continue reading to fix common problems in lawn care or gardening. 

Best Time to Fertilize Grass

When to fertilize your lawn really depends on where you live. Because there are three zones in the US, the cooler zone near the north, the transition zone, and the warm zone near the south. That’s how you get calm and warm seasoned grass.

If you have cool-season grasses, such as Kentucky bluegrass or fescue, the best time to fertilize is in early spring, from February to April, and in fall, from September to November.

If you have warm-season grass, such as Bermuda or Zoysia, the best time to fertilize is in late spring, from April to June, and again in summer, from June to August.

When fertilizing the lawn, apply it every 6-8 weeks during the growing season. Avoid fertilizing during extreme heat or drought, or winter.

How to Apply Lawn Fertilizer

Suppose you know the best time to fertilize grass, and then you should know how to apply lawn fertilizer as well. If you sprinkle it, then grass grows in one area and lawn burns in another. Always use a broadcast or drop spreader for granular fertilizer to get even coverage. If you have liquid fertilizer, you can use a backpack sprayer for a bigger lawn or use a hose-end sprayer or watering can for a smaller lawn, and walk steadily to avoid over-application. 

Wear safety equipment like long gloves, full-sleeved apparel, and a mask. Do not fertilize before heavy rain to prevent runoff.

Mow and rake before applying fertilizer to the lawn to ensure nutrients reach the soil. Water after applying granular fertilizer to activate nutrients. You can use a standard garden hose or an automatic method, such as the Aiper IrriSense, to cover up to 4,800 sq. ft., saving you time and hassle. Water the lawn before applying liquid fertilizer, if specified. 

Extra Lawn Care Tips for a Lush Lawn

Fertilizing your lawn is just one part of your lawn care. There is more to getting a lush and healthy lawn. If you don’t take these steps of lawn care, you might have the best lawn in the neighbourhood, but no one can see it because of too much taller grass.

• Test your soil regularly: Purchase a soil testing kit from a garden center or university extension. You will know the health of your lawn soil and what nutrients it is deficient in, and pH issues. The ideal pH for lawn soil is 6.0-7.0.
• Water wisely: Your lawn probably needs 1 inch of water per week, including rainfall. You have to water deeply and do it infrequently to promote stronger roots.

You cannot just let go of the hose on the ground to water the lawn. You get the most out of your fertilizer if you can water it like rain. But it takes a lot of time. You can try out an automatic watering system, but it requires a significant amount of time to set up. If you have an Aiper IrriSense, it's a DIY setup that takes less than 15 minutes. You can simply water by deciding how much to water and automate it via an app to ensure your fertilizer nutrients are absorbed efficiently.

• Mow correctly: Let grass grow to 4.5 inches and then cut to 3-3.5 inches. Leave clippings to act as a natural mulch. 
• Aerate Annually: This releases soil compaction, which can occur due to walking or lawn equipment. This opens entryways to the root zone for water and nutrition. Thus, improving your water and nutrition absorption of the lawn. Do it before fertilizing.
• Avoid common mistakes: Do not over-fertilize your lawn. Do test your soil to see what nutrients it lacks and get proper fertilizer for adequate grass growth. Do not fertilize during drought to avoid lawn damage.

Troubleshooting Fertilizer Issues

Why are you having a bad lawn? When you do not fertilize based on recommendations, you get issues like unhealthy growth or lawn burn, soil pH imbalance, nutrient runoff, or weak growth. These are results of improper lawn care. Here’s how to fix them:

• Lawn burn: This happens because of over-fertilization in the lawn. You get brown grass or dead grass spots in your lawn. To fix this, water your lawn so much more for a week to flush out excess salts. Overseed your lawn if you still face lawn burns.
• Yellowing grass: It is a sign of nitrogen deficiency. To get greener grass, apply a high-nitrogen fertilizer. Do soil tests before fertilizing your lawn. You can try out NPK 20-0-10 fertilizer at recommended rates if it's only nitrogen-deficient.
• Uneven growth: Uneven growth is caused by uneven fertilizer application. To prevent this, use a spreader and apply in overlapping patterns like vertical, then horizontal.
• No results: If you get no results from fertilizer, then this may indicate poor soil pH or could even be the wrong fertilizer. Retest your soil to see its health and nutrient deficiency. Based on test results, adjust your approach accordingly.

It is important that you monitor your lawn regularly. Based on that, adjust practices accordingly. If you are still facing issues, then seek professional help.

Conclusion

To grow your garden or lawn, it depends on your soil health. Check the soil with a soil testing kit and the pH of your soil. Add those lacking nutrients in the soil from fertilizer.

Fertilizer is just nutrition for your soil, comes in an NPK ratio, i.e., nitrogen, phosphorus, potassium. The ideal NPK ratio depends on soil test results and lawn area. If you get the wrong fertilizer, then you see yellow grass or even no results. Constantly water your lawn. Or automate it with tools like Aiper IrriSense, which features smart irrigation systems that allow you to schedule watering for up to 4800 sq. ft. with just 15 minutes of DIY setup.

How should you start lawn care? Start with a soil test, measure your lawn, and follow our guide to keep your lawn green and healthy throughout the entire season.