Most homeowners in the Oklahoma area have bermudagrass lawns, which by now have come out of winter dormancy, greened-up, and are well on their way to growing so that mowing is necessary every week or so. You don’t need to “feed” your grass however to have it looking great, as most homeowners believe. Grass, like all green plants, are unique in that they can make their own “food” from the basic elements of soil minerals, sunliqht, water, and air. As long as these are present, and the environmental conditions are right, then beautiful, green and growing grass appears in your lawn.
If you do your own fertilizing, you may buy a bag of fertilizer that says “Turf Food” on it. It’s not food at all! It’s usually a combination of naturally occurring mineral elements, synthetic organic elements, and maybe even some natural organic elements. Most urban soils do not have all the necessary nutrients required for good plant growth. In an urban situation, that usually means having the greenest lawn on the block! Just keep in mind though two important points:
- The greenest lawn, while it is beautiful, may not be the healthiest lawn.
- There is much more than just fertilizer necessary for a green, healthy lawn.
Warm-season turf, such as bermudagrass and zoysiagrass, require fertilization from 2-5 times per growing season (April—September) to perform their best. How many times per season a homeowner should fertilize depends upon soil type, irrigation, grass type, fertilizer rates and types, and most of all—homeowner expectations. Bermudagrass especially loves nitrogen, the most important element in found in turf fertilizers. Nitrogen is the element mainly responsible for the nice green color of turf, and for the growth of turf. Nitrogen is constantly being used up, lost, and changed due to many complicated processes you only need to know if you are in college, or if you are in the lawncare business like me. (If your lawncare provider doesn’t know, maybe you should switch!) The bottom line is this: if you want a green lawn, you need to apply nitrogen fertilizer to your turf several times per season. If you don’t, it’s not that your grass will die, but it will be thin, weed-infested, and just will not look good, as your neighbors may have already informed you.
When you go to the local garden center, or the big box store, the choices, brands, and all those numbers on the bag may be confusing. There are three primary nutrients that most turfgrasses need and may be deficient in the soil—nitrogen, phosphorus, and potassium. Nitrogen, the most important one, is the first number listed. Phosphorus and potassium are listed second and third. Therefore, when you buy a 50 pound bag of a fertilizer labeled 29-3-10 for example, you have 14.5 pounds of actual nitrogen, 1.5 pounds of phosphorus, and 5 pounds of potassium in that 50 pound bag. It’s good to have some slow-release nitrogen as part of the nitrogen source. This allows you to apply more fertilizer each time without burning the turf, and extends the nitrogen release so that your grass will stay green a little longer in between fertilizations. Slow-release nitrogen is more efficient, with more of the nitrogen being used by the turf and on a more consistent basis. Less is lost due to leaching or runoff. Using slow-release nitrogen will add to the cost of the fertilizer however, which is why most of our competitors don’t use it, or use very little of it. Our Round 2 blend is a 36-1-3, with from 50% to 70% slow-release nitrogen in several different forms. This unique blend applied at a heavy rate provides enough nitrogen to get the grass green and growing, while slowly releasing more nitrogen over about an 11 week period. With this product, it allows us to then apply Echelon in our Round 3 for weed-control, since there is still adequate nitrogen in the soil being utilized from the Round 2 treatment, before we again go back to granular fertilizer with Round 4.
Oklahoma State University (go Pokes!) recommends that 1 pound of actual nitrogen be applied per 1000 sq. ft of warm-season turf per growing month. In other words, about 5 to almost 6 pounds of actual nitrogen/1000’ per season should be applied from late spring to early fall, and our 7-step LawnAmerica Program does just that. The last fertilization of the season should be in August or September. With that final early fall fertilizer, it’s good to decrease the amount of nitrogen, and increase the potassium (the last number). It’s not healthy or wise to apply excess nitrogen in late summer and early fall, as the turf is preparing to go into winter dormancy. Potassium will help the turf develop a stronger root system and help with disease resistance.
Phosphorus, the middle number, is usually found in great abundance in Oklahoma soils. Therefore, we really don’t apply very much during the season. The only time a high-phosphorus fertilizer such as 10-20-10 should be applied is during the seeding process. New fescue seedlings for example will benefit phosphorus applied during the fall seeding process.
A common mistake for homeowners is to fertilize Cool-season turf such as fescue in the same manner as bermudagrass. Fescue does not need as much nitrogen as warm-season turf to perform well. In fact, if fescue is over-fertilized during summer, burning and/or turf disease can occur. Apply lighter rates of fertilizer to fescue. Fescue needs fertilizer earlier in the season, since it is a cool-season grass. Late fall is the most important time to fertilize fescue, since it will help the turf come out stronger and greener the following spring. At LawnAmerica, we use a custom blended organic soil amendment named Soil Builder with a very low amount of slow-release nitrogen on . fescue during summer, which totally eliminates the possibility of over-fertilizing with nitrogen.
All granular fertilizers need to be watered into the soil so that the nutrients can move down into the root zone to be absorbed by the plant. Turf fertilization, while very important for the color, density, and health of the lawn, is not the only ingredient for lawn success. If overdone, it can be just as detrimental as not enough. There are many other cultural practices, such as proper mowing, irrigation, and weed-control necessary for a healthy turf.