What Fertilizer to Use for Lawns? A Quick & Easy Guide

Not all fertilizers are made alike, and not all of them will produce the results you want.

This means the fertilizer you choose will depend on the type of plants you have and their needs at the current stage in their lives.

In this article, we’ll go over the different types of lawn fertilizers you can get and how to use them. Let’s get started.

Which Nutrients Do Plants Need?

Most plants need 17 essential nutrients to grow: 14 from the soil (through fertilizers or organic materials) and three from the air and water. Essential plant nutrients include:

• From water and air: Carbon, hydrogen, and oxygen
• Primary macronutrients: Nitrogen, phosphorus, and potassium
• Secondarymacronutrients: Magnesium, calcium, and sulfur
• Micronutrients: Boron, copper, iron, manganese, molybdenum, nickel, zinc, and chlorine

The soil under your lawn will have all of these nutrients available to some extent. But this will depend on the following:

• Soil texture (silt loam, loam, loamy sand): Finer soils (with more clay) have a higher ability to hold on to nutrients than sandy soils with little to no clay.
• pH balance: When pH is too high or too low, this will increase or decrease the nutrient availability and biological activity in the soil. A pH between 5.5 and 7.0 is ideal for most plants.
• Organic matter: This includes decomposed plant and animal material in the soil. It improves soil structure and provides a slow-release source of nutrients as it decomposes.

The best way to understand how many nutrients the soil contains is through a soil test. This will help you understand organic matter content, soil type and texture, and pH, NPK, and lime requirements. You can use fertilizers to improve the soil’s nutrient availability based on the test.

What Is Fertilizer?

Fertilizers are organic and inorganic materials that contain nutrients that can be absorbed directly by plant roots and foliage. They help plants improve their structure, yields, and defense mechanisms.

Commercially available fertilizers contain at least one plant nutrient: a macro- or micronutrient, with the nutrient content being guaranteed by the numbers found on the bag. This nutrient analysis shows the percentage by weight of nitrogen (N), phosphorus (P), and potassium (K) or other compounds.

Types of Fertilizers

Fertilizers are either organic or inorganic. Understanding the differences between these types will help you choose the right fertilizer for your needs.

1. Organic Fertilizers

Organic fertilizer is made from processed or composted animal and plant waste material. It’s more environmentally friendly compared to chemical fertilizers, provides nutrients to your lawn through decomposition, and improves the soil’s drainage capacity.

These fertilizers are generally slow-release and take a few days to weeks to break down into plant-available forms, although this varies. For instance, fish emulsion releases 85% of its nutrients during the season it is applied, compared to 5-10% for plant-based compost.

That said, organic fertilizers can be more expensive and may contain weed seeds, especially in fresh or improperly composted manure.

Here are some examples of organic fertilizers:

• Blood meal
• Bone meal
• Fish fertilizer
• Corn gluten
• Dried poultry litter
• Manure
• Compost
• Seaweed extract
• Cottonseed meal
• Green manures
• Worm castings

2. Inorganic Fertilizers

Inorganic fertilizers are man-made. They can be fast-acting in liquid form and slow-release in the form of pellets/granules.

These fertilizers are easy to use for calculating application rates but have a higher potential for leaching and burning because of their concentration. But they are generally cheaper than high-quality organic fertilizers per pound of nutrient.

Some types of inorganic fertilizers include:

• Nitrogenfertilizers: These include nitrate-based fertilizers like ammonium nitrate (AN), calcium ammonium nitrate (CAN), calcium nitrate, ammonium sulfate, and anhydrous ammonia.
• Nitrogen fertilizers with inhibitors: These fertilizers have foliar, delayed, and control-release properties to reduce the chances of nitrogen denitrification, volatilization, and leaching.
• Phosphorus fertilizers: These include ammonium polyphosphate (APP), di-ammonium phosphate (DAP), triple superphosphate (TSP), mono-ammonium phosphate (MAP), and single superphosphate (SSP).
• Potassiumfertilizers: These include potassium nitrate (KNO3), potassium sulfate (K2SO4), and potassium chloride (KCl).
• Calcium, magnesium, and sulfur fertilizers: They include calcium nitrate, calcium carbonate (lime/dolomite), gypsum, potassium sulfate, and potassium magnesium sulfate.
• Micronutrient fertilizers: These include boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), zinc (Zn), and chlorine (Cl).
• Inhibitors: They include nitrification inhibitors that slow down the conversion of ammonium to nitrate. They also contain urease inhibitors, which reduce the amount of highly polluting ammonia emissions into the air.

Choosing a Fertilizer Based on Common Nutrient Issues in Plants

If you can’t get a soil test done, check for the following signs of distress to get an estimate of your fertilizer needs:

Issue	Cause
Yellowing leaves	Nitrogen deficiency
Too much leafy growth and delayed fruiting	Too much nitrogen
Brown leaf edges	Potassium deficiency
Tip burn and blossom end rot	Calcium deficiency
Stunted, spindly growth in sandy soil	Lack of sulfur
Purple or reddish tint on leaves	Phosphorus deficiency
Yellowing between leaf veins (older leaves)	Magnesium deficiency
Yellowing between leaf veins (younger leaves)	Iron deficiency
Small, deformed leaves/fruit	Zinc deficiency
Poor fruit or seed development	Boron deficiency
Yellow or pale green leaves overall	Manganese deficiency
Curling, mottled leaves	Molybdenum deficiency
Weak stems and pale green color	Copper deficiency
Slow growth and pale leaves	General nutrient imbalance

5 Things to Know Before Using Fertilizer

You’ve chosen the right fertilizer for the plants. Great. But here are five things to know before using these products:

1. Fertilizer Won’t Help Plants With Disease

Fertilizer helps you fulfill the nutritional needs of the plants, but it doesn’t cure plant disease issues caused by pests, bacteria, and fungal infections.

In fact, over-fertilizing causes lawns and gardens to become more prone to stress, which worsens their health.

Find out what’s wrong with the plants first and treat that issue, such as by improving drainage, removing infected parts, or using pesticides before fertilizer.

2. The Amount of Fertilizer Needed Decreases as Organic Matter Increases

If the soil is rich in organic matter like compost and worm castings, it will already have many of the nutrients it needs. Plus, the matter will steadily release increased amounts of nutrients as it decomposes.

This means that you may not need to use general NPK fertilizers. Instead, you might only need to give the plant or lawn one nutrient it’s missing in the exact quantity required.

3. Too Much Fertilizer Can Cause Weak Growth and Encourage Pests

You might be tempted to add a little more fertilizer than required, but that doesn’t help. Excessive nutrients, especially nitrogen, can cause overly quick, weak, and leggy growth. This often attracts insects like aphids and increases the risk of fungal diseases.

Plus, you might also create a nutrient imbalance in the soil, which can harm its long-term growing potential. It can also cause the leaching of nutrients into waterways, where they may create algal blooms that kill aquatic plants and fish.

4. Fertilizer May Damage Drought-Stressed Plants

Fertilizing drought-stressed plants can do more harm than good. That’s because fertilizer needs water to dissolve and be absorbed. When the plant is already struggling to absorb water or hasn’t been fed in a while, the added salts in fertilizers will make this problem worse and cause leaf burn, root damage, and increased stress.

5. Always Water the Soil Before Fertilizing

Dry soil can cause fertilizer salts to concentrate around the roots, which can cause damage like yellowing, wilting, or stunted growth. You can avoid this if you irrigate the soil beforehand.

This will create a buffer zone that’ll help nutrients disperse evenly, and it goes double if you’re using liquid or granular fertilizers because it reduces the risk of over-concentration.

How to Use Fertilizer

Here are general recommendations on how to fertilize the plants:

1. For Lawns

If you’re looking to keep your lawn looking healthy and weed-free, fertilizing is a must. But your timing, lawn size, and amount of fertilizer need to be precise. Here’s how to fertilize your lawn:

• Multiply your lawn’s length by its width to calculate its square footage.
• Subtract the areas you don’t want to fertilize, like the deck, driveway, and garden.

Next, use the following table to determine the amount of fertilizer you’ll need:

Numbers on the fertilizer bag	Amount of fertilizer needed to supply 0.9 lb nitrogen/1,000 sq. ft.	Amount of fertilizer needed to supply 0.5 lb nitrogen/1,000 sq. ft.
6-0-0	15 lbs	8.3 lbs
10-0-4	9 lbs	5 lbs
15-0-6	6 lbs	3.3 lbs
20-0-5	4.5 lbs	2.5 lbs
30-0-3	3 lbs	1.7 lbs
35-0-5	2.5 lbs	1.4 lbs

2. For Fruit Plants

You should fertilize your fruit plants based on the soil test results and plant needs. If the soil test report shows that your potassium levels are “high,” you’d be limited to nitrogen-only fertilizers.

In this case, it’s recommended to feed 1.5 ounces of nitrogen per 100 sq. ft. You can find out how much fertilizer you need by dividing the recommended fertilizer amount by the percentage of nitrogen in your chosen fertilizer.

3. For Trees/Shrubs

Most of the time, you won’t have to fertilize your trees and shrubs, especially when they’re mature. But if the soil test indicates that the plant needs fertilizer, follow its recommendations.

For instance, if it says potassium and phosphorus are adequate, you only have to focus on nitrogen. Here are the application rates for shrubs and small/large trees:

Plant	Nitrogen quantity
Shrub	0.25 oz./plant
Small tree	0.5 oz../plant
Mature tree	2-3 lbs/1,000 sq. ft.

If you’re fertilizing a small tree, the easiest way to provide this nutrient is through broadcasting granular fertilizer on the surface of the soil under the tree, near the trunk to the drip line (ends of branches).

Let’s say you use a 10-6-4 fertilizer. To find out how much you’ll need, divide the recommended quantity (0.5 oz/plant) by the nitrogen content of the fertilizer in decimals. So, 0.5/0.10 = 5 ounces.

Make Fertilization Less Complicated With SunCo

Knowing what fertilizer to use requires paying attention to several factors at once. You need to know the soil’s nutrient quantity, soil type and texture, plant type, season, area size, and many other factors to get fertilization right. This can become overwhelming.

That’s where we come in.

At SunCo, we’ve been fertilizing lawns, trees, and shrubs for over 20 years across the Midwest. We’ve worked on drought-damaged lawns and severely nutrient-deficient soil to bring plants back to life.

If you’re looking to get your lawn or garden looking healthy again, give us a call!