Wednesday, September 26, 2018

Don't Put Your Lawn to Bed Yet! by Rebecca Anderson

Photo by Donna Duffy
With fall approaching, everyone is looking forward to a break from the hot weather and summer yard chores of mowing and watering.  It's true that the grass isn't getting tall as quickly as it did in June, but that doesn't mean that it has quit growing.  In the fall, grasses are forming tillers: side shoots that thicken the grass and help it recover from losses that occurred in the more stressful times of summer. This side growth still requires some water, so don't roll up the hoses or blow out your sprinklers yet.  Water application of 0.5 to 0.75 inches per week is recommended by CSU for the months of September and October.  This is significantly less than the recommended 2.25 inches per week in the hottest months of summer, but is still more than our rainfall totals for most weeks.

For some lawns, fall can be a good time for fertilizer application. Only green, growing lawns of cool season grasses (bluegrass, ryegrass, fescue) will benefit from fall fertilization. Warm season grasses (buffalo grass, blue grama, zoysia grass, Bermuda grass) should not be fertilized after September 1. Fertilizer needs to be watered in with 0.5 inch of water after application, so if your community is implementing a watering cut-off day, make sure the fertilizer is applied before that date. If your lawn has already gone dormant and is brown, fall fertilizer won't help much.  It is better to wait until spring. Check out the fact sheet Fall Fertilization of Colorado Lawns During Drought for more information.

Fall is also the best time to control several pests in the lawn. It is especially good for managing perennial broadleaf weeds (dandelion, clover, bindweed, plantain, thistle, etc.). These weeds respond best to herbicide application if they are actively growing at the time of application. You don't like to think you're watering the lawn just for the weeds, but if that means the weeds take up more herbicide and die back more thoroughly, you'll have a lawn that's in much better shape next year.  Fall and winter watering also discourage winter mite activity, leading to a healthier lawn in the spring.

While lawn chores can start slowing down over the next few weeks, doing just a little more watering and maintenance in the fall can help set the stage for a healthier lawn in the spring. You can find more details about fall lawn care on the following CSU resource, The Importance of Fall Lawn Watering.