The Northeast Lawn Calendar

Stay off the lawn when it's frozen or snow-covered — frozen grass blades snap and leave dead patches that show up in spring.

If you didn't get dormant seeding down in November/December, you missed that window — the next chance is frost seeding in March.

Good month to sharpen mower blades and get equipment serviced before spring demand hits repair shops.

Watch the forecast for freeze-thaw cycles (freezing nights, thawing days) — that's your frost seeding window starting soon.

Order grass seed and soil test kits now, before the spring rush.

Still no fertilizer. Cool-season grass isn't actively growing yet and won't use it.

Frost seed bare or thinning areas while the ground still freezes at night and thaws by day — that heaving action pulls seed into the soil for you.

Rake up winter debris (branches, matted leaves) so grass underneath can breathe.

Get a soil test done. Results take a couple of weeks and you'll want them before you fertilize.

Apply crabgrass pre-emergent once soil temperature hits about 55°F — forsythia blooming is the classic sign it's time. Look for prodiamine (longest-lasting) or dithiopyr (more forgiving if you're late). Seeding this spring? Use mesotrione instead — the others stop grass seed from sprouting too.

First mow of the year once grass reaches 3–3.5 inches. Never cut more than a third of the blade at once.

Skip heavy spring fertilizing. It pushes top growth you'll just have to mow more, at the expense of root strength you'll want in summer. If you feed at all, use a light slow-release nitrogen with a 0 in the middle (no phosphorus).

Spot-treat broadleaf weeds like dandelion and clover now, while they're actively growing and take up herbicide well. A "three-way" broadleaf killer (2,4-D, dicamba, mecoprop) covers most of them; add triclopyr for clover and violets. Skip days above about 85°F.

Keep mowing height at 2.5–3.5 inches. Taller grass shades out weed seedlings before they can establish.

Start watching for grub damage (spongy, discolored patches) as the month goes on.

Apply a preventive grub control product now if you've had grub problems before — it needs to be down before eggs hatch in midsummer.

Raise your mowing height as temperatures climb. Taller grass has deeper roots and handles heat better.

Water deeply and infrequently (about 1 inch/week total) rather than a little every day — it trains roots to grow down, not sideways.

Hold off on fertilizer during heat stress — it can burn a stressed lawn and does little good this time of year anyway.

Water in the early morning to reduce evaporation and disease risk. Avoid evening watering, which keeps grass damp overnight.

A lawn that goes brown and dormant in a heat wave usually isn't dead — cool-season grass does this on purpose. It'll green back up in fall rain.

Late August is when you start prepping: aerate compacted soil and dethatch if your lawn has a spongy thatch layer over half an inch.

Order seed now for a mid-to-late September planting — good seed sells out during fall rush.

Re-test soil if it's been a couple of years, so you know what fall fertilizer program actually to run.

Mid-August through mid-September is prime time to overseed thin areas or start a new lawn from seed. Aim for at least 45 days before your first hard frost.

Apply a starter fertilizer (higher phosphorus — the middle number) at seeding, or wait until new grass sprouts and feed the whole lawn. States that restrict phosphorus generally still allow it for new seed.

Keep new seed consistently moist — light, frequent watering until it germinates, then taper to deeper, less frequent.

Apply your main fall fertilizer application — this feeding builds root strength for winter more than any spring application ever will. Use a mix of quick- and slow-release nitrogen with no phosphorus unless your soil test calls for it, about 1 lb of nitrogen per 1,000 sq ft.

Keep mowing as long as grass is growing, gradually lowering the height for your last few cuts of the season.

Deal with any lingering broadleaf weeds now — they're storing energy for winter and herbicide is very effective this time of year. The same three-way broadleaf killer from spring works here.

Give a final feeding of quick-release nitrogen once the grass stops growing but is still green. "Winterizer" on the bag is mostly marketing — nitrogen is what matters, and extra potassium only helps if your soil test shows it's low. Check your state's cutoff date first (New Jersey, for example, ends homeowner fertilizing on Nov 15).

Keep raking leaves off the lawn. A wet mat of leaves left all winter smothers grass and invites snow mold.

Once the ground is cold but not yet frozen, you can dormant seed bare spots — the seed sits tight until spring.

Dormant seed while soil is cold (under 50°F) but not frozen solid — once it freezes hard, you're done until frost seeding in March.

Drain fuel from mowers and other gas equipment before long winter storage.

Do a final walk of the lawn for low spots or drainage issues to fix once the ground thaws.