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.
Do: get your mower ready for the season
• Having your mower ready to go before the season starts will save you down time during the growing season.
• Sharpen blade. Having sharp mower blades are very important to turf aesthetics and health. To learn how to sharpen your blade, check out this video: https://www.youtube.com/watch?v=JMy1j9NR89o&list=UUMFY6zEWe6uJEYakzOofhIg
• Change oil if necessary and clean air filter. Video here: https://www.youtube.com/watch?v=oxgbMDdT6bQ&list=UUMFY6zEWe6uJEYakzOofhIg &index=10
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, goosegrass, and bermudagrass. 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
Do: apply a pre-emergent herbicide
• Annual grassy weeds such as crabgrass and goosegrass 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 western Kentucky, a pre-emerge herbicide should be applied prior to around April 7. 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 (Figure 1).
• 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. For more information on controlling weeds in your lawn, check out the following publications: http://www2.ca.uky.edu/agcomm/pubs/AGR/AGR208/AGR208.pdf http://www2.ca.uky.edu/agcomm/pubs/AGR/AGR218/AGR218.pdf
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 out grow 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 (Figure 2), as soil temperatures are adequate at this point for germination of tall fescue or Kentucky bluegrass.
• For more information on establishing or renovating lawns, see: http://www2.ca.uky.edu/agcomm/pubs/AGR/AGR50/AGR50.pdf https://www.youtube.com/watch?v=nDuciEPWVvU
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 (Figure 2).
Figure 2. Seasonal growth variations for cool-season grasses.
• 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 1/3 of the leaf in one mowing.
For example, if you want to maintain your lawn at 3 inches, mow when the height reaches about 4.5 inches. Removing more than 1/3 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:
o Tall fescue 3 inches or taller
o Kentucky bluegrass 2.5 inches or taller
• For more information on mowing your lawn, see the following publication: http://www2.ca.uky.edu/agcomm/pubs/AGR/AGR209/AGR209.pdf
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.
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