Fall is the best time to improve your grass. And with our high temperatures and lack of rainfall, lots of lawns might be needing special care this year.
This summer has not been kind to our lawns. The combination of heat and drought has left many of them looking worse for the wear. Water, of course, is the key to having a good-looking lawn, but it alone might not fix drought-damaged grass. This fall, your lawn might need special care beyond regular weeding and feeding to bounce back next spring.
Here's what to do and when do it:
Fall is the best time to reseed thin, straggly looking lawns. But you should wait until temperatures moderate before planting grass seed. Typically, the seeding season begins in mid- to late August in northern Minnesota and ends around the third or fourth week in September in the Twin Cities area and the southern part of the state.
If you seed much later than this, the grass may sprout this fall, but its chances of surviving the winter will be greatly diminished. When you plant at the right time, the seedlings will still look thin and weak this year, but they should come back looking thicker and more robust next spring.
Where existing grass is thin, scruff up the soil surface to create a receptive area for seeds. If a lot of your lawn is thin, you might want to use a core aerator or slice the soil surface with a power rake.
Spread a fertilizer formulated specifically for use with newly planted grass with the seed or shortly after seeding, then water lightly two or three times a day to keep the soil moist.
Continue to mow the lawn, based on the height of existing grass. Once seeds begin to germinate, water less frequently, but more deeply.
If areas of your lawn remain dry and dead-looking after the fall rains resume, you may want to lay new sod. Use a sod cutter to skim off the old grass and its roots. Scuff up the soil as you would for seeding and rake a starter fertilizer into the area you plan to sod.
You should be able to lay sod safely several weeks later than you can seed, but you must water frequently so the roots knit down into the soil.
While lawn grasses may have struggled this summer, many weeds were able to keep right on growing despite the heat and drought. Try to get rid of them before they drop seeds into the soil.
Fall is the best time to go after perennial weeds, but if you plant grass seed, you won't be able to use weedkillers in those areas. (Even herbicides that don't damage established lawns will take a toll on young grass seedlings.)
That leaves two options: pulling weeds (which is easiest when the soil is moist) or carefully spot-treating individual weeds by touching their leaves with a cloth saturated with a nonselective herbicide such as Round Up.
If temperatures have moderated and the drought has broken by the end of August, you can apply a standard lawn fertilizer, then water it into the soil.
If it's still hot and dry, fertilize only if you can water regularly or wait until conditions improve, and fertilize then. (Your lawn will benefit from a second application of fertilizer at the end of October.)
If you fertilize when the air temperatures are cool, nutrients in the fertilizer will be used to strengthen and develop roots and runners rather than more leafy top growth, which will make for a healthier, better-looking lawn next year.
Deb Brown is a garden writer and former extension horticulturist with the University of Minnesota. To ask her a gardening question, call 612-673-9073 and leave a message. She will answer questions in this column only.