Lawn care calendar for Massachusetts: when to fertilize and seed

Feeding months are UMass Extension's program table; towns on Cape Cod and the islands have their own rules.

Which grasses grow where in Massachusetts

UMass Extension's grass selection guide covers cool-season turf. Kentucky bluegrass spreads by rhizomes, tolerates cold and wear, and goes semi-dormant in hot, dry spells. Perennial ryegrass establishes fast, so it is used alone or at about 20 percent of a mix. Turf-type tall fescue is slow to establish but is heat and drought tolerant and takes moderate shade; UMass puts its nitrogen need at 2.5 to 3 pounds per 1,000 square feet per growing season. Fine fescues suit shade, drought and low fertility, need 1 to 2 pounds, and do poorly in hot, humid conditions.

UMass says tall fescue has the highest drought avoidance of the cool-season species. Endophyte-enhanced cultivars of ryegrass, tall fescue and fine fescue resist leaf-feeding insects such as billbugs, sod webworms and chinch bugs.

Frost dates from NOAA

Dates are the NOAA 1991-2020 normals for the last spring and first fall 32 F freeze at 50% probability. Boston Logan International averages April 4 and November 9. Worcester Regional Airport averages April 23 and October 21.

Our arithmetic: Boston has about 219 days between those dates and Worcester about 181, 38 days fewer inland.

Spring

UMass's program table puts the spring nitrogen application after about 50 percent green-up, at 1.0 to 1.5 pounds in a two-application program and 0.75 to 1.0 pound in three- and four-application programs, with 25 to 100 percent slow-release nitrogen depending on the program. Some programs skip spring feeding altogether.

Crabgrass germinates in spring, and UMass says that renovating in spring and early summer without a pre-emergent herbicide fails more often than not, because of crabgrass pressure. Raising the mowing height reduces the light reaching seed and helps most in the spring and early summer germination peak.

Summer

Summer nitrogen goes only on irrigated turf, and only in the four-application program. UMass advises against applying fertilizer to drought-dormant, cold-dormant or brown turf, which the regulation repeats as a legal limit.

Soil type decides how often to water. One inch of water wets clay soil to about 5 inches, loam to about 7 inches and sand to about 15 inches, To soak the soil to a depth of 12 inches takes about 0.75 inch on sand, 1.5 inches on loam and 2.5 inches on clay.

Fall

Late summer and early fall is when UMass says to renovate: summer annual weed pressure is minimal, and weeds that do sprout in new seedings seldom grow big enough to hurt establishment before cold weather ends them. The Labor Day feeding drives recovery from summer stress and tillering.

A late-fall application is described as delicate, appropriate only for intensively used, high-value turf, and applied after the last mowing when shoot growth has stopped but the turf is still green. UMass says it is normally not warranted on residential lawns and should be avoided in environmentally sensitive areas.

What 330 CMR 31.00 requires

The regulation for non-agricultural turf and lawns took effect June 5, 2015; the text below is the version Mass.gov published in January 2018. Phosphorus-containing fertilizer, defined as lawn fertilizer above 0.67 percent available phosphate, can be applied only when a soil test taken within three years shows a need, or to establish a new lawn or renovate in the first growing season. No fertilizer goes on frozen, snow-covered, saturated or flood-prone soil, nor when heavy rain is predicted, nor on drought-dormant or brown turf, nor on hard surfaces, and not as a de-icer.

Keep 20 feet back from surface water with a broadcast spreader, or 10 feet with a drop spreader, rotary spreader with a deflector or targeted spray. No fertilizer in a Zone I of a public water supply well or within 100 feet of surface water used for public supply, and nothing in excess of UMass's annual rates. Cape Cod, Martha's Vineyard and Nantucket have local rules of their own. The lawn fertilizer calculator on this site shows pounds of product per 1,000 square feet so you can stay inside the UMass figures.