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When to apply Fertilizers3/26/2014


When to apply fertilizers - Courtesy of Greenview

Leading scientists recommend applying nitrogen fertilizers to cool season grasses in the spring and fall only, since this is when the grass is actively growing. They recommend the application of 2.5 to 3.5 pounds (lbs.) of nitrogen per 1,000 square foot per year applied as follows to cool season grasses:

  • Spring (April–May) — The best time to apply fertilizer is after 3 mowings. Apply 0.5 to 1 lb. of nitrogen per 1,000 square feet to support growth and to build-up reserves for summer.
  • Summer (June–August) — Cool season grasses go dormant in the summer and do not require fertilizer until the temperatures drop with the start of fall. Warm season grasses grow all summer long and require an application of fertilizer to sustain this growth and remain healthy.
  • Fall (September–November) — The most important time to fertilize is in the fall to help the grass develop a strong root system. Apply 1.5 to 2.5 lbs. of nitrogen per 1,000 square feet (Use the higher amount if your lawn is Kentucky bluegrass or perennial ryegrass, soil is sandy, or grass clippings are not returned to the lawn.)
  • Late Fall (October–December) — an application of slow release winterizer fertilizer will benefit the grass plant as the roots continue to grow through the winter (until the ground freezes).  Be sure to look for a winterizer fertilizer with a high percentage of slow release nitrogen.