Fertilizer needs to be applied soon to lawns

Awesome is the only way to describe the power of nature. It is amazing how something so beautiful can become so destructive and deadly.

Despite the rash of tornadoes, hail and severe weather, many gardeners are enjoying the timely rains that have kept newly planted flowers, trees and shrubs alive and healthy.

With this in mind, it is time think about our lawns. This is a good time to apply the first fertilizer application of the year. Here are some tips to help keep your lawn lean and green for the next several months:

Cool-season lawns such as bluegrass and fescue go through two major growth spurts. The first is just finishing up, and the second will occur this fall. The springtime “flush-of-growth” characteristic of these grasses is beginning to taper, so the fertilizer you apply now will be less likely to cause excessive shoot growth than if you fertilized in March or April.

Generally, all lawn fertilizers are basically the same. All of them contain some proportion of nitrogen, phosphorus and potassium. What is unique is the ratio and delivery method of these nutrients and other “stuff” they contain such as sulfur, iron and other micronutrients. When purchasing lawn fertilizers, try to choose one that has some portion of the nitrogen as slow release.

Slow-release nitrogen sources promote controlled growth and, to use a human analogy, put the turf on a diet as the stressful summer weather approaches. Few fertilizers supply ALL the nitrogen in the slowly available form. However, such products that are widely available include Milorganite and other “natural organic” fertilizers.

Synthetic forms of slowly available nitrogen include sulfur-coated urea, water insoluble nitrogen, ureaformaldehyde and IBDU. In this case, the greater the proportion of slowly available nitrogen the better.

The next burning question is how much should you apply. Application rate is based on square feet and percent nitrogen of the fertilizer.

The suggested rate of fertilizer is one pound of nitrogen per 1,000 square feet of area. To determine the square feet of your lawn, multiply the length by the width and then subtract out the area for the house, drive, gardens and flower beds. To determine how much fertilizer to apply, divide 100 by the first number of the three-number analysis on the bag. The answer will be the number of pounds of fertilizer that should be applied to 1,000 square feet of lawn.

When applying fertilizer, use these good “cents” tips to not waste any. Do not apply fertilizers with added weed killers or insecticides if they are not needed. Do not apply fertilizer when heavy rain is expected. Fill spreaders over hard surfaces for easy spill cleanup. Shut off the spreader when crossing over hard surfaces. And sweep fertilizers off hard surfaces and back into the yard.


— Bruce Chladny is horticulture agent at K-State Research and Extension-Douglas County. For more information, call him at 843-7058 from 8 a.m. to 5 p.m. weekdays.