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

Law columns summarize P.L.2010, c.112 as enacted in January 2011; check the current statute before relying on a date.

Which grasses grow where in New Jersey

Rutgers treats New Jersey lawns as cool-season turf: Kentucky bluegrass (seeded at about 2 pounds per 1,000 square feet), tall fescue, fine fescue and perennial ryegrass (4 to 6 pounds each). Tall fescue is prized for quick establishment, drought tolerance and traffic tolerance, fine fescue for shade and dry, poor soil, and perennial ryegrass for speed.

Mowing height is 2.5 to 3.5 inches, particularly in summer. Continuous mowing at 2 inches or lower weakens turf and raises pest problems. Mow when the grass reaches 3.75 inches if you cut at 2.5, or 5.25 inches if you cut at 3.5.

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 Newark Liberty International the average last spring frost is April 2 and the average first fall frost is November 10. At Atlantic City International the dates are April 18 and October 29.

Our arithmetic: Newark has about 222 days between those dates and Atlantic City about 194, a 28 day difference inside one small state. Rutgers splits its seeding dates at Trenton for a similar reason.

Spring

Fertilizing is legal from March 1, but Rutgers suggests that a lawn fed in late summer and late fall can skip the early spring feeding and wait until late spring, which also avoids putting nitrogen down when leaching is more likely. Early spring is the second-best time to seed or renovate, with more weeds, crabgrass in particular. A siduron pre-emergent is the last step when you renovate in spring.

Fertilize a seeded lawn two to four weeks after the grass comes up, with 3 to 5 pounds of 20-10-10 per 1,000 square feet, and keep the top two inches of the soil moist until seedlings root.

Summer

Rutgers advises against fertilizing in the hot months, or at most using a slow-release product at a lower rate. Dollar spot is active from late May through October and brown patch commonly appears from June to September.

Water when the lawn shows stress, not on a timer. Wet the soil to about 6 inches, which lasts about a week on heavier soils and two to three days on sandy ones. Lawns can survive New Jersey's short droughts without watering, especially at lower nitrogen and higher mowing.

Fall

Late summer to early fall is the primary season for seeding and renovating, because evenings are cool, fall rain is likely and crabgrass has stopped germinating. Rutgers suggests about 1 pound of nitrogen per 1,000 square feet on a full-sun lawn in late summer or early fall, and again in late fall if needed. Lime is best in fall or early winter, and dethatching in fall once thatch is thicker than half an inch.

Stop mowing when growth has essentially ceased. Those fall feeding dates have to sit inside the legal window: nothing for homeowners after November 15, and nothing for professionals after December 1.

New Jersey's fertilizer law

P.L.2010, c.112 applies to turf statewide and overrides local rules. For people other than professional applicators it limits fertilizer to 0.9 pound of total nitrogen per 1,000 square feet per application, no more than 0.7 pound of it water-soluble, using a product that is at least 20 percent slow-release, and 3.2 pounds of nitrogen a year. Professionals may apply up to 1 pound per application and 4.25 pounds a year.

No phosphorus on turf unless a soil test from the last three years shows a need, you are establishing or repairing turf, or it is placed under the soil surface at the roots. Do not fertilize within 25 feet of a waterbody, or 10 feet with a drop spreader, a deflector-equipped rotary spreader or a targeted spray. No fertilizer on pavement, in heavy rain or when rain is forecast, or on saturated soil. The lawn fertilizer calculator on this site turns a bag label into pounds of product, which is the quickest way to stay under 0.9 pound of nitrogen per application.