Lawn care calendar for New York: when to fertilize and seed

Dates shift with the weather; follow the signs in the text.

Which grasses grow where in New York

Cornell says that in New York and areas with similar conditions, most lawns are a mixture of cool-season grasses and weeds. Roots begin growing in spring before the blades green up, top growth flushes in cool, moist weather, slows in summer heat and returns in fall.

Top growth continues until the average daily temperature stays below 50 F, and roots keep growing through the winter until the soil freezes. Brown grass in summer or winter is usually dormant, not dead. For a bare spot, Cornell suggests a perennial ryegrass seed mixture.

Frost dates from NOAA

Dates are the NOAA 1991-2020 normals for the last spring and first fall 32 F freeze at 50% probability. At New York City (Central Park) the average last spring frost is March 30 and the average first fall frost is November 20. At Buffalo the dates are April 24 and October 26, and at Albany Airport April 27 and October 15.

Between Central Park and Albany the last spring frost is four weeks apart on these averages (computed from the dates).

Spring

Cornell's advice for spring is to do less. If the lawn is thick with vigorous grass, skip the spring feeding, because soil nutrients, clippings and a late-season feeding supply enough. Mow often enough to avoid clumps of clippings, which can mean every 5 days in the spring flush, and keep the blade sharp.

The state law covers the practical details. Use a drop spreader or one with a shield, keep fertilizer 20 feet from water, sweep spills off pavement and skip the job if heavy rain is expected within 2 days.

Summer

Cool-season grass slows in summer heat and may turn brown, but drought rarely kills it. Cornell says most lawns survive on a fraction of an inch of water over a 3-week period. If you water, apply no more than 1 inch a week in the morning, slowly enough that nothing runs off.

Mow at 3 to 3.5 inches, since shorter lawns need more fertilizer and water. Mow every 7 to 14 days in the rest of the growing season and not at all during a summer drought.

Fall

Fall is the main season. Plant from the middle of August through September, when cooler temperatures, moisture and less weed competition help seedlings. Spread seed in two directions at half the label rate, rake it in no deeper than 1/8 inch and keep the surface moist.

About 2 to 3 weeks after seedlings emerge, apply 1 pound of nitrogen per 1,000 square feet, and wait until the grass reaches at least 4 inches before the first mowing. Overseeding thin lawns works best after core aeration.

Cornell Cooperative Extension and soil testing

The Cornell Turfgrass Program publishes the lawn guide and sends soil testing questions to your local Cornell Cooperative Extension office. Collect 10 to 20 subsamples at a steady depth, dry them and send them to a testing lab. Results take 1 to 2 weeks.

Keep the soil pH between 6.0 and 7.5, and use lime only if a test shows a pH of 6.0 or lower.