Lawn Care Requirements in September for Thornton, Colorado

Thornton Colorado lawns benefit from proper winterization tasks performed in September.Grass lawn image by Dan Marsh from Fotolia.com

September in Thornton, Colorado, means cooling temperatures and preparing the lawn for winter. While the chance of snow in Thornton in September is slim and temperatures won't dip below freezing until October, it's still a good time to get the lawn ready for the cold and snow that will arrive soon.

Considerations

Thornton is located in the Denver metropolitan area and has a climate similar to Denver. The average high temperatures for Thornton in September are in the mid-80's, gradually cooling into the upper-70's by the end of the month. Rainfall may occur and the overnight temperatures start to fall into the 40's. The lawn will still be green in September but the time is definitely right to prepare it for winter.

In late September, before the lawn turns brown, treat the lawn with a nitrogen-rich fertilizer. Water the lawn prior to fertilization to allow the product to work properly. For effective results, use one pound of fertilizer for every 1,000 square feet of lawn. Increase this amount if you don't fertilize at other times during the season. Another important requirement is to rake the leaves before snow falls. This will help prevent mold and allow the sun to reach the soil.

Thornton is located in a drought-prone area and the city occasionally imposes watering restrictions that can dry out the grass or create brown spots throughout the lawn. Even when the city is not imposing water restrictions, they still encourage citizens to use water sparingly during the watering season. Watering limitations can affect your lawn and limit the effectiveness of fertilizer. If the lawn is not entirely dead in September, it is still possible to fertilize. However, the benefits of fall fertilization will not show up until spring.

Weeds can continue to grow throughout the winter so it's a good idea to get rid of them before the snow season. If your lawn contains broadleaf weeds like knotweed, or annual weeds including crabgrass, you don't need to worry as much about fertilization. The first few frosts of the year, which usually begin in October, will kill off these weeds. To kill dandelions or thistle that may have invaded your lawn, use an herbicide like 2,4-D. If you don't want to use chemicals on your lawn you can always weed by hand.