Spring lawn care

Dave Robson

The main purpose of spring lawn care is to get the grass through the summer. Cool season grasses such as Kentucky bluegrass, perennial ryegrass, and the fescues need to develop a strong root system in order to survive summer's heat and dry conditions.

Ideally, our lawn care calendar should be from September 1 through August 31, and not April 1 through March 31. This would encourage nine months of cool-season growth before summer's conditions. Thinking that lawn care starts in the spring only allows a couple months of growth before harsh environmental conditions.

However, there are several practices that you can use to maximize your lawn's chances of surviving the summer.

Early spring fertilizer applications should be avoided, if possible. Early fertilizers tend to green-up the lawn, which isn't visually bad. However, adding nitrogen fertilizers tends to stimulate shoot development at the expense of root growth. Cool spring temperatures favor root growth more than shoot growth, which creates a denser and deeper root system for the turf. That deeper and denser root system means a better chance of survival for the summer.

If and that's a big if — you must fertilize in the early spring, do so at a low rate. Think about it 10 times before finally committing. Typically, homeowners have applied about 1 pound of actual nitrogen per 1,000 square feet. This is probably too much.

Instead, apply fertilizer at one-fourth (1/4) the recommended rate. For example, if the fertilizer bag says it will cover 5,000 square feet, it should cover 20,000 square feet. The low rate of fertilizer will green up your turf but not over stimulate shoot growth.

A full application of fertilizer could be applied during the middle of May (Mother's Day weekend) If you intend to water the lawn throughout the summer. Another alternative would be to use a slow-release fertilizer that would provide nutrients throughout the summer. Slow release fertilizers need less moisture and seldom burn turf.

Crabgrass pre-emergence chemicals can be applied in the early spring. Crabgrass germinates when the soil temperature has been 55 degrees or warmer for seven to 10 consecutive days. Crabgrass also needs light, air and open space to germinate. Look for those bare areas in the lawn and apply the crabgrass controls in these areas. Avoid applying it in thick, lush stands of turf where it's not needed.

April 1 tends to be a good time to apply crabgrass preventers. Most of the compounds have a residual time of four to six weeks. A second application around the middle of May will help control late germinating crabgrass as well as warm season annual grass weeds.

Avoid crabgrass-fertilizer combinations. These will stimulate the shoots to grow at the expense of the roots. There are plain "crabgrass killers" on the market; if you don't find one, ask if one can be ordered.

Make sure to read and follow all the directions on the chemical label.

As soon as the grass needs cutting, mow it. Don't wait. Most cool season grasses should be cut at a 2 to 2 1/2 inch height. This means mowing the lawn when it reaches 3 to 4 inches to avoid cutting off more than leaves. If you allow the grass to get tall before mowing, you run the risks of stressing the plants and encouraging diseases.

Sharpen your mower blades. This is essential. A sharp blade makes a clean cut. Blades should be sharpened at least twice a year.

David Robson is an Extension Educator, Horticulture, at the Springfield Extension Center, Cooperative Extension Service, University of Illinois. You can write to Robson in care of Illinois Country Living, P.O. Box 3787, Springfield, IL 62708. Telephone: (217) 782-6515. E-Mail: robsond@idea.ag.uiuc.edu

16 ILLINOIS COUNTRY LIVING MARCH 1998