Most of us who have lawns in our area of Maryland have lawns composed of cool-season turfgrasses, like tall fescue or Kentucky bluegrass. Perhaps with a smattering of weeds for textural interest. Cool-season grasses remain green during the winter, as opposed to warm-season grasses, which turn brown after the first hard frost and don’t green up until late spring. Zoysia grass is our warm season grass here. In dry summers, cool-season grasses that aren’t watered go dormant (turn brown) until rains reappear, and they really take off as the days grow shorter and cooler in autumn. Turfgrasses best utilize fertilizer when they are actively growing, so most fertilizer applications to cool-season grasses are made in the fall, warm season grasses in late spring/easrly summer.
One of the side-effects of improper fertilizing is contamination of water. Fertilizers applied to sidewalks or frozen surfaces, or applied right before heavy rains, can be washed into storm drains and eventually to the Chesapeake Bay. Green lawn: good; Green Bay: bad–unless you happen to be a Wisconsin football fan. The same fertilizer nutrients that green up your lawn also cause excess algae to grow in the Bay, which is damaging to other aquatic life.
To reduce fertilizer runoff to the Bay, the State of Maryland regulates the application of lawn fertilizers by homeowners. It is illegal for you to fertilize (“feed”) your lawn between November 15 and March 1. So: if you intend to fertilize this fall, you only have a few weeks left to make the application. Remember to avoid application before heavy rain, and always, always read the label instructions on the bag for rates of application and other information.
To read more about the Maryland Lawn Fertilizer Law, see:
For lots of information on growing turfgrass in Maryland, see the Maryland Home and Garden Information Center:
by Larry Hurley, Behnke horticulturist