The basic do’s and don’ts of spring lawn care Dr. Gregg Munshaw, Turfgrass Extension Specialist University of Kentucky With spring right around the corner and daffodils, dogwoods and forsythia about to bloom, homeowners get the itch to spend some time in their yards. The following are some do’s and don’ts for spring lawn care on cool-season grasses (tall fescue, Kentucky bluegrass) in Kentucky. Don’t: apply nitrogen • The vast majority of nitrogen fertilizer should be applied in the fall. Fall applications improve the health of the lawn and result in a greener lawn in the winter, less spring mowing, and less weeds, heat stress, need for water, and disease problems in summer. • Nitrogen applied in spring and summer promotes growth of warm-season weeds such as crabgrass, goose grass, and Bermuda grass. Further, high amounts of nitrogen in spring and summer can result in increased damage from white grubs in the soil. Adult beetles are attracted to the lush lawns and high nitrogen levels restrict turf rooting which compounds the damage from the white grubs feeding on the turf roots. More information on fertilizing lawns can be found in this video: https://www.youtube.com/watch?v=eTlVnAyR_rw Spring is not the best time of the year to apply nitrogen Do: apply a pre-emergent herbicide • Annual grassy weeds such as crabgrass and goose grass begin to germinate in the spring and depending on the thickness of the lawn, the amount of weed seed in the soil, and the environmental conditions, untreated populations of these weeds can outcompete and take over your desired lawn species. By applying a pre-emergent herbicide prior to weed germination, weed numbers can be drastically reduced and your lawn can have the chance to flourish without fighting weeds for space, nutrients, light, and water. •In central and eastern Kentucky, the spray before date is usually around April 15. • A pretty good indicator plant for knowing when to apply a pre-emergent herbicide by is forsythia. Generally, a pre-emergent application should be applied before forsythia drops its blooms. • Do not apply weed and feed products as we don’t want to be applying nitrogen to our cool-season lawns in the spring. • If you miss the pre-emerge window and weeds begin to germinate, your best bet is to apply a post-emergent application to small seedlings as most pre-emergent products do not work after germination. Don’t: seed in the spring • The best time of year to seed lawns is in the early fall. The concern with planting in the spring is that there is significant competition between seedlings and grassy weeds (and weeds almost always outgrow our desired species) and the immature seedlings can struggle with summer heat and drought more so than a mature lawn. • If you have to seed in the spring, plant around the time that forsythia is in bloom, as soil temperatures are adequate at this point for germination of tall fescue or Kentucky bluegrass. Do: mow at regular height • Once the grass starts to grow in the spring, it will really start to take off. We see most of the growth in the spring of the year, it slows down in the summer, and then ramps up again the in autumn. • Because the grass grows at a high volume in the spring, it’s best to not let the height get too long before mowing. Ideally, never cut off more than a third of the leaf in one mowing. For example, if you want to maintain your lawn at three inches, mow when the height reaches about four-and-a-half inches. Removing more than a third of the leaf blade results in a reduction in root growth. • Mowing at taller heights has been shown to reduce crabgrass populations without the use of herbicides. Recommended heights for lawn grasses in Kentucky are: tall fescue three inches or taller; Kentucky bluegrass two-and-a-half inches or taller. By following these basic do’s and don’ts, you can start your lawn off on the right foot this spring and enjoy it more and work on it less throughout the year. Call the Woodford County Extension Office at 859-873-4601 with any lawn care questions.
Horticulture
