Most people think about fertilizing their lawns in the spring and early fall. But, November is also the time to think about applying fertilizer.

"Late fall fertilizers are often called 'winterizer fertilizers' or just winterizers," says David Robson, University of Illinois Extension horticulture educator. "This may be the most important fertilizer you apply to your lawn – especially if you've never applied any."

Winterizers don't provide immediate results. You won't see anything this winter except maybe some granules here and there that don't work into the soil or break down with late fall and winter rains and snow. That's due to the nature of the fertilizer and the season of the year. The benefit of winterizers is what they do to the root system throughout the winter months and the effect on shoot development next spring.

Robson says the best winterizers are slow-release fertilizers, and usually low analysis, with nitrogen levels between 10 and 15 percent. Nitrogen is the first number listed on the fertilizer bag. The fertilizer granules break down slowly over late fall, winter and spring based on soil temperature, moisture and microbial activity. During this time, the roots, which are growing as long as the ground isn't frozen, are absorbing and storing the nutrients until the air temperature is ideal for the bluegrass, ryegrass or fescue to use it for shoot growth and green color.

When air temperatures finally warm in the spring, the stored nutrients are immediately available and the turf is green and thick – usually by mid-March. A thick stand also means less reliance on crabgrass preventers since crabgrass problems are minimized due to a lush turf.

Winterizers are put on a week after the last mowing of the year. Since the last mowing is difficult to predict, Robson suggests applying winterizer to the lawn during Thanksgiving weekend. If you missed that weekend, winterizer could still be put on the following week.

Most applications are based on 1 pound of actual nitrogen per 1000 square feet of turf. Like straight lawn fertilizers, most winterizers are formulated for this rate. Read and follow the directions on the label. And, it's a good idea to water in the winterizer before storing the garden hoses and sprinklers for the winter.

For more lawn care tips, check out our Fall Lawn Care Guide, available from your local Extension office, or online at: http://web.extension.uiuc.edu/regions/SIfamily. Click on "Around the House" and then "Tip of the Month."