September Lawn Care

By John Wilson, Extension Educator

Last week we flipped the calendar over to a new month, and September can be the most important month to get your bluegrass and tall fescue lawns back in good condition after the stressful months this summer, although this year wasn’t as bad as many. I had to mow my lawn every four to five days in August which is unheard of. Normally it’s about every eight to 10 days! I guess Mother Nature thought I could use the exercise.

There are some lawns with brown patches from disease problems this summer. Some of those will fill in as temperatures cool in September, but if they don’t, rake up as much dead plant material as you can, then overseed thin areas by mid-September to give new grass a chance to germinate and get established this fall. Remember to keep the top inch of soil moist, but not too wet, after seeding or overseeding if you don’t get timely rains. One nice thing about seeding in the fall is you generally won’t have the weed competition you do when seeding or overseeding in the spring.

If you haven’t fertilized yet this fall, apply about 3/4 to 1 pound of actual nitrogen per 1000 square feet of turf now, and apply a similar amount toward the end of October. That last fertilization in late October is the most important one you make all year so don’t forget to do that about Halloween-time. This will also give you a slower, more uniform green-up next spring rather than the fast flush of growth you get if you fertilize too early. Avoiding the rapid flush of growth in the spring can also reduce the chance of disease and drought injury later in the growing season.

If you have a thatch buildup, over ½ inch of thatch, power rake your lawn by mid-September. This will give the turf a chance to recover after this operation. Rake up and compost or dispose of the dead plant material after power raking. If the thatch in your lawn is not that thick, consider core aerating rather than power raking. It isn’t as hard on the turf and will improve root growth and water infiltration.

If you have problems with perennial broadleaf weeds such as dandelions, ground ivy or white clover, mid-September to mid-October are the best times to apply broadleaf weed killers. The plants are busy making food and sending it to the roots for next year’s growth. Herbicides applied then will also be translocated to the weed roots, giving you better control. If you wait until after a light frost, you can also reduce the potential for injury to ornamental plants.

If you had your mowing height raised for the summer, leave it at this height this fall rather than lowering it as was once recommended. As lawns start to grow faster in the fall, remember to mow more frequently so you don’t remove more than 1/3 of the total height of the grass. Removing more than that with one cutting will cause unnecessary stress on the turf.

As leaves start to fall, don’t let these accumulate because they can smother areas of grass if allowed to become too deep… especially if you get some rain that packs them down. Mow your lawn and mulch in the leaves before they become too deep. If you luck out and the wind is from the right direction, the leaves may blow off your lawn and onto your neighbor’s lawn… reducing the amount of mowing or raking you’ll need to do.

Besides fertilizing your lawns one last time in late October, the other thing you need to remember is to water your lawn well later this fall, but before the ground freezes, if you don’t get timely rains. This will help your turf go into the winter in a healthier condition and reduce the chance of winterkill.

Following these steps can help your lawns recover from the stress of summer, go into winter in a healthy condition, and reduce problems next year. For more information on fall lawn care, contact your local Nebraska Extension office.

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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