Fall lawn fertilization
Fall is the best time of year to fertilize Colorado's bluegrass lawns. Promotions about "lawn winterization" may sound mysterious, but there's nothing magical about it. Simply fertilize with nitrogen sometime during late September to early November along the Front Range, and earlier in the mountains.
Apply at least one pound of nitrogen per 1,000 square feet. If you're using a natural organic fertilizer like dehydrated poultry waste, you can double the rate. Also double the rate for non-organic fertilizers if this is the only time of year you fertilize, or if you fertilize just one other time in early summer.
Remember that turf must be green when nitrogen is applied. Also, make sure that the soil is moist so the nitrogen will dissolve easily. If not, irrigate and wait a day before fertilizing. Fertilizer applied to very dry, cold soil or to dormant turf won't be used efficiently.
While nitrogen is the most important nutrient, there is no harm if fertilizers also contain some phosphorous or potassium.
The benefits of fall fertilizing include a healthier turf before winter, a healthier root system, and stimulating a turf that greens up earlier in the spring without excessive top growth. Fall fertilization produces dense, green spring lawns without the mowing chores that come with spring fertilization. It should be a part of every good lawn care program.
For more information, see the following Colorado State University Extension fact sheet(s).
For more information, see the following Planttalk Colorado™ script(s).
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Updated Tuesday, November 19, 2013