Masterful Gardening: Fall is the Time for Winterizing Your Lawn

by Nelson Peterson, Master Gardener

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To winterize your lawn properly, fertilizing should have been accomplished during September or early October. An application of potassium (potash) might be of some benefit to assist your lawn when it goes through winter stress but we do not recommend applying nitrogen at this time.

Do not fertilize your lawn during the winter; wait until the spring. It is wise to allow Northeast Florida lawns to go dormant from November through February.

You may apply pre-emergent herbicide during this time but it is best used when temperatures are above 75 degrees.

For information on spring fertilizing and the type of fertilizer to use, see our website at

Mowing requirements may be reduced significantly because of slow turf grass growth, but the mowing height should remain the same as during the growing season.

St. Augustine grass should be cut at 3-4 inches, Centipede grass at 11/2-2 inches, Bahia grass at 3-4 inches and Bermuda at 1/2-11/2 inches.

By maintaining these cutting heights, the grass will be less stressed when colder temperatures are encountered.

As during the growing season, mower blades should be sharpened on an as-needed basis.

Never scalp or cut grass too short as root growth directly corresponds to blade length.

Mulching or bagging grass clippings is unnecessary unless the grass has a disease.

Mulching has advantages such as the recycling of grass clippings that contain fertilizer back into the ground, and it prevents the grass clippings from being sent to a landfill.

Mulching has disadvantages if grass is cut when wet or if cut more than a third of its height. Neither of these practices is recommended. Both will cause clumps of grass to be left behind rather than mulching the grass effectively.

An easy check to determine if mulching is occurring properly is to look behind your mower as you mow. If you can see the mulched grass then you might be mowing wet grass, or your mower may not be working properly for mulching.

We recommend you irrigate no more than a half-inch to 3/4-inch per zone during any season. The idea is to train the roots to follow the water as it percolates down through the soil.

This practice will strengthen the grass and reduce the stresses brought on during periods of cold and drought.

Irrigating with less water and more frequent watering causes the grass roots to stay closer to the surface and thus more susceptible to stress brought on by cold and drought.

Irrigating during the dormant season should be extended to 10-14 day intervals.

The frequency of irrigation during all seasons is regulated by the St. Johns Water Management District regulations. During Eastern Standard Time (first Sunday in November until second Sunday in March), once per week irrigation is permitted.

Homes at addresses that end in an odd number can water only on Saturday.

Homes at addresses that end in an even number can water on Sundays. Irrigation is not allowed between 10 a.m. and 4 p.m.

Remember that 95 percent of the grass' water-holding capability is located in the grass blades, so by cutting the grass at the recommended height, the majority of the water is still available to the grass.

Keep in mind too, that during cooler periods less evaporation of water through the grass blades occurs.

Nelson Peterson is an active Master Gardener volunteer with the Nassau County Extension Service and the University of Florida/IFAS.

For information on the Master Gardener program and application requirements, contact Nassau County extension director and horticultural agent Becky Jordi at 530-6350 or



Nelson Peterson

Nelson Peterson lives on Piney Island and is an active Master Gardener volunteer with the Nassau County Extension Service and the University of Florida/IFAS.