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Your lawn has specific fertilizer requirements, depending on both what soil type you have, and the particular type of turfgrass you are growing.
Fertilizers contain essential nutrients that will help your lawn to survive. This buyers guide will discuss different types of fertilizers, what nutrients they contain, how to test your soil, soil pH, and how to read the fertilizer numbers on packages.
Hopefully, once you read our lawn fertilizer reviews, you’ll be able to pick out the best product for your grass.
Your soil can supply some of the nutrients that your grass needs, but not all of them. An actively growing lawn requires a good bit of energy. Fertilizers can help your lawn by controlling and reducing weeds, replacing nutrients that have been lost to grass clipping removal and leaching (a loss of plant nutrients washed away from soil by rainwater).
It can also promote new root and leaf growth, and help your lawn to recover from any pest damage or foot traffic.
*Note, your needs may vary depending on grass type, climate, soil conditions and overall grass condition.
Different Types of Fertilizer
Fertilizers are divided into two main categories – granular fertilizers and liquid fertilizers.
Granular fertilizers are applied dry, from a shake container or with the help of a mechanical spreader, and then watered. There are two main types of granular fertilizer – slow release and quick release.
Slow-release fertilizer contains WIN (Water Insoluble Nitrogen) which is available in polymer-coated or sulfur-coated varieties and can last for 8-12 weeks. Quick-release fertilizer contains WSN (Water Soluble Nitrogen), can last 3-4 weeks and will provide nitrogen immediately to your lawn.
Liquid fertilizers need to be applied every 2-3 weeks, are quick-acting, and are absorbed through roots or leaves. Although usually used for container plants, there are also some varieties that can be used on lawns.
What Nutrients Does Your Lawn Need?
Your lawn needs both macronutrients (chemicals that are required in large quantities for plant development and growth) and micronutrients (chemicals that are needed in trace amounts for plant growth and development).
Primary macronutrients are Nitrogen (essential for leaf growth and vivid green color), Phosphorus (essential for root growth), and Potassium (also known as Potash), which is important for resistance to disease and drought, and for root development. Lawns also need carbon, oxygen, hydrogen, magnesium, calcium, and sulfur, but these are usually present in the soil or air.
Micronutrients are only needed in small amounts and include chlorine, boron, copper, cobalt, manganese, iron, molybdenum, zinc, and nickel.
Testing Your Soil
In order to know which nutrients are required by your lawn, a soil test is essential. You can either buy a home test from the garden center (which aren’t extremely accurate) or send in a soil sample to the closest cooperative extension office.
The results will tell you exactly what chemicals to add to your soil. They will also tell you if your soil is alkaline, acidic, or neutral. The pH of your soil is a measure of soil alkalinity (sweetness) or soil acidity (sourness). A pH scale goes from 0 to 14, with 7 being neutral. A reading below 7 is acidic, and a reading above 7 is alkaline.
Alkaline soils (a pH over 7) are primarily “sweet” clay soils with a high pH level that usually contain an overabundance of calcium, magnesium, and sodium. Alkaline soils can be improved by adding ground rock sulfur to the soil to increase acidity, as well as a fertilizer that’s high in phosphorus.
Acidic soil (a pH below 7) could have too much manganese, iron, or aluminum, which might tie up phosphorus and make your soil too acidic for lawn growth. The easiest way to raise an acidic soil level is to add some pulverized limestone to your soil.
The chemicals in limestone that can neutralize your acidic soil are calcium and magnesium carbonate. Be careful not to add too much lime, or you might end up with zinc, manganese, and iron deficiencies, or even a nasty overgrowth of bacteria. If you have a neutral soil (a pH of 7), congratulations! You can choose any fertilizer that strikes your fancy.
How to Read and Calculate Fertilizer Labels
The majority of fertilizer bags show 3 bold numbers on their labels, separated by dashes.
- The first number will be the total percentage of N (Nitrogen) coming from ammonium, nitrate, and/or urea.
- The second number tells you what quantity of P (Phosphate) is available.
- The third number, K (Potash) shows you how much soluble potash is contained.
So if your number is 20-10-20, that means 20 percent Nitrogen, 10 percent Phosphate, and 20 percent Potash.
Your completed soil test, combined with your local lawn care specialist, can determine from these numbers the exact fertilizer product you will need.
Also, your lawn care specialist can advise you on the best fertilizer, depending on what type of turfgrass you are growing.