Our fool spring has many itching to get out in the yard and get to work sprucing up the lawn; however, it is important to consider that it could still be too early. To properly take care of problems in the lawn, it is important to fully understand what we are trying to control.
Spring lawn maintenance often includes a combination of the following: a pre- or post-emergence herbicide, overseeding, aerification, dethatching, fertilization, or an insecticide. When making these applications, it is important to apply maintenance practices at the right time.
When making herbicide applications, time of application is very important. Some weeds such as crabgrass begin to germinate when minimum soil temperatures reach 55 to 60 degrees for 7 consecutive days, meaning herbicide applications should not be made that far in advance of these germination requirements. Soil temperature and ambient air temperature are not the same thing; to determine soil temperature, visit the Illinois State Water Survey. Typically, we reach soil temperatures of 55 to 60 degrees around April 1st. It is also important to understand that temperature can have a negative effect on the efficacy of a herbicide, so it is important to know the requirements of the herbicide used.
If you are interested in having a manicured lawn but also want to reduce chemical inputs, there are some alternative options to manage weeds. Having a dense stand of grass will provide competition to crowd out weeds. If your lawn consists of mostly warm season grass, you may want to incorporate some cool season grass into your stand to create competition to winter annual weeds that germinate earlier in the spring. Weeds will often grow where grass won’t; some weeds like yellow nutsedge commonly grow in poorly drained areas, so by alleviating any compaction issues and increasing soil drainage through aeration and adding organic matter, these areas will become more favorable for growing grass. You may also consider only spraying areas that have weeds.
If you plan to overseed or reseed your lawn, you’ll want to hold off on herbicide applications. When herbicides are applied, seeding should be delayed until 30 days after the application. If we wait to apply pre-emergent herbicides until soil temperatures rise to 55 to 60 degrees for 7 consecutive days (around early April), that pushes seeding back to the 1st of May. Spring seeding should be done before mid-April; the more it is delayed, the less time the grass has to become established before it starts getting too warm. The ideal time for seeding a lawn is in late August to September.
Everyone wants a plush green lawn; however, the early season application of fertilizers promotes aboveground growth but not root development. In the event of a dry summer, shallow root development results in a reduction in efficiency of water uptake. Soil sampling should be done to check if nutrients are necessary. If additional nutrients are needed, fertilizer applications can be made in mid-May. Consider watering the turf to incorporate fertilizer to prevent burn. A slow release fertilizer requires less moisture, reduces chance of burn, and provides nutrients overtime as the fertilizer breaks down. Not only is topdressing with compost a great way to provide a low rate of nutrients to your lawn, but it also adds organic matter to your soil which helps to build a healthier soil and lawn.
Many homeowners will apply an insecticide to control grubs in their lawn, but these insecticides also control beneficial insects in the soil. It is suggested to only apply an insecticide when grub populations have reached around 10 to 12 grubs per square foot (peel up sod in areas where you think you may have a problem and sift through the soil).
There’s a lot to think about when discussing proper application and maintenance practices in lawn care; never hesitate to reach out to your local Extension office to ask questions.
Good Growing Tip: In the case of applying pesticides, more does not mean better. A lot of research has been done to figure out the exact rate in which you should apply these products, so it is important that you follow the label when making applications.
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