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Date: August 19, 2003
Name is a clue: Fertilize cool-season grasses Sept. - Oct.
(RICHMOND, VA) - As September approaches, cool-season grass lawns in Virginia need attention because fall is the best time to fertilize these lawns.
Results include better density and root growth, less spring mowing, fewer weed and disease problems, as well as increased drought tolerance. Common in most of Virginia, cool-season turfgrass species include tall fescue, Kentucky bluegrass and perennial ryegrass. They grow actively in spring and fall, and may go dormant during hot, dry periods when not watered.
Appropriate fertilization depends upon soil type and how quickly the nitrogen is released. As these components vary, so will amounts and timing.
Slow-release fertilizers are more than 50 percent water-insoluble nitrogen, sulfur-coated urea or of a natural organic source. Nitrogen is gradually released and less likely to result in leaching - a good choice for sandy soils.
Generally more expensive, these fertilizers can save time because applications are less frequent than with other fertilizers. Calculate the nitrogen contained in the fertilizer and apply an amount that is one pound of nitrogen per 1,000 square feet of grass between Aug. 15 and Sept. 15.
Repeat between Oct. 1 and Nov. 1. Skip the second application with a low-maintenance lawn. Fertilizer applied later in fall may still be releasing nitrogen in spring. In particular, natural organic fertilizers such as cottonseed meal and manures release nitrogen as they decompose, so apply them before mid-September.
Quick-release fertilizers, those less than 50 percent water-insoluble nitrogen, are not good in sandy soils. Otherwise, apply it in an amount that is one pound of nitrogen per 1,000 square feet of grass in September, October and November. Quick-release fertilizers are good in instances such as a newly planted vegetable garden.
If used on a lawn in the spring, a quick-release fertilizer application should be between May 15 and June 15 - in an amount that contains only ? pound of nitrogen. Plant roots must be active when it is applied or certain elements may be leached through soil, polluting groundwater.
Contact Virginia Cooperative Extension for fertilization rates and timing if you have warm-season grass (Bermuda, zoysia, or centipede grass, for example).
For a month-by-month guide to an environmentally sound lawn and garden or a lawn fertilization brochure, contact the Virginia Department of Conservation and Recreation at 1-877-42WATER. Or call your local Virginia Cooperative Extension Master Gardeners for water-wise landscaping techniques and garden layout tips. Add hardy plants to your landscape - request regional (mountain, Piedmont and coastal) native plant lists from DCR or download them from www.dcr.virginia.gov. Also contact the Virginia Native Plant Society at (540) 837-1600.
-30-editors' note: October - protecting soil through the winter