Spring Lawn Care


By John Wilson

Extension Educator

Despite some of the advertisements you may have seen or heard recently, the best advice I can give you now is to slow down on lawn care, especially fertilization and crabgrass control. For cool season turfgrasses like bluegrass and tall fescue, lawn care in late March and April should include hand raking to remove debris, edging, mowing, core aeration, power raking and seeding, overseeding or sodding.
For the season’s first mowing, mow lawns at a height of about two and one-half inches. It is not necessary or recommended to “mow as low as the mower will go”. This can scalp turfgrass and result in root loss or slowed root growth.
Core aerate with a machine that pulls out soil plugs to relieve soil compaction and encourage root growth. This is one of the most important practices we can do for lawns. If possible, core aerate once a year. Homeowners tend to power rake often, but core aeration should be done more often than power raking.
Power rake if the true thatch layer exceeds one-half inch. You can measure true thatch by cutting a plug out of the lawn. True thatch is the reddish brown mat found between the soil and the base of grass blades. It is made up of dead roots, rhizomes, and stems.

John Wilson

John Wilson

A small amount of thatch, up to one-half inch, is beneficial. It protects the plant crown from temperature extremes and traffic. Too much thatch can lead to root growth in the thatch layer making it more susceptible to drought damage; and fertilizers are tied up in thatch and become less available to roots.
True thatch is most common on highly maintained lawns. It builds up whether grass clippings are caught during mowing or left on the lawn. Core aeration will slow the build-up of thatch; but once the true thatch layer exceeds one-half inch power raking is needed to remove it.
Seeding, overseeding, and sodding cool season grasses can take place throughout the month of April. The sooner these can be planted the better to allow time for establishment before the heat of summer. Ideally, soil temperatures should be at least 40 degrees Fahrenheit for grass seed to germinate. Seed will germinate quicker at soil temperatures around 45 to 50 degrees F.
Delay fertilization until late April. Research has shown early spring fertilization, when soil temperatures are still cold, leads to an increase in diseases, such as summer patch; increased heat stress due to a less vigorous root system and possible loss of nitrogen due to leaching or run-off.
Delay applying preemergence herbicides for crabgrass control. These products kill the seedling as the seed germinates and begins growth. They are only effective when the seed is germinating. Crabgrass is a warm season grass and optimum soil temperatures for germination are 60 degrees, so most crabgrass germinates from mid May through June. So delay preemergence applications until the first of May so they are full strength when crabgrass is germinating.
For more information on spring lawn care, contact your local UNL Extension office.

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