Why fall beats spring
- Warm soil, cool air. Ideal conditions for cool-season grass seed.
- Less weed competition. Crabgrass dies off in fall.
- No conflict with crabgrass preventer, which also stops grass seed in spring.
- Two root-building seasons (fall and the next spring) before summer heat.
What aeration does
Core aeration pulls small plugs of soil from the lawn. That relieves compaction so water, air and nutrients reach the roots, and it gives new seed direct contact with soil. The plugs break down on their own within a couple of weeks.
Picking seed
Cornell Cooperative Extension recommends matching seed to conditions: fine fescue blends for shade, tall fescue for heavy traffic and drought, and bluegrass with ryegrass and fine fescue for sunny, well-kept lawns. See best grass seed for Long Island.
Watering new seed
Keep the top inch of soil damp until the seed sprouts, with short waterings once or twice a day. Once the new grass is growing, water less often but deeper. Suffolk County Water Authority customers water on an odd/even schedule and not from 10 a.m. to 4 p.m.
First mows
Suffolk County's guidance is to start mowing new seedlings once they reach about 2 inches, then move back to the regular height of about 3 inches after three or four mowings.
Core aeration vs. spike aeration
Core aeration pulls plugs of soil out of the ground, which relieves compaction. Spike aeration pokes holes without removing soil, which can press the soil tighter around each hole. For compacted Long Island lawns, core aeration is the standard choice.
Seeding rates by grass type
| Seed mix | Cornell rate (new lawn) |
|---|---|
| Bluegrass, ryegrass, fine fescue (sun) | 3 to 4 lbs / 1,000 sq ft |
| Fine fescue mix (low maintenance) | 4 to 5 lbs / 1,000 sq ft |
| Fine fescue blend (shade) | 4 to 5 lbs / 1,000 sq ft |
| Tall fescue blend | 7 to 10 lbs / 1,000 sq ft |
From Cornell Cooperative Extension of Nassau County. Overseeding an existing lawn usually uses less.
Signs your lawn needs aeration
- Water puddles or runs off instead of soaking in
- Grass thins in high-traffic areas
- A screwdriver is hard to push into moist soil
- A thick, spongy layer of thatch at the soil surface
