YardThisWeekGet frost and soil alerts

Lawn timing: pre-emergent, fertilizer and seeding

When to put down crabgrass pre-emergent, feed and seed, keyed to soil temperature and your frost dates. Timing only, never rates: Always follow the product label.

General timing from public extension sources. Local conditions vary. Not a substitute for the product label or your local extension office.

Every ZIP page shows this week's pre-emergent status from the nearest soil station or a labeled estimate.

Pre-emergent

Spring pre-emergent (first application)

Open the window when the 5-day mean 4-inch soil temperature reaches 50°F; aim to have the product down and watered in before it holds at 55°F, because crabgrass begins germinating at sustained mid-50s temperatures.

Skip on lawns seeded in the past few months, and in spring if you plan to seed soon; the label gives the waiting period. Water in after application as the label directs.

Pre-emergents work only before seeds sprout; once crabgrass is up, they do little.

Split / second spring application

About 6–8 weeks after the first application, if the label allows a second one. Extends the barrier into early summer, when goosegrass (germinates at warmer soil, about 60–65°F) and late crabgrass flushes come up.

Pre-emergent barriers break down with heat and rain; splitting keeps coverage through the long Southern germination season.

Fall pre-emergent for annual bluegrass (Poa annua) and winter weeds

Apply as the 4-inch soil temperature falls toward 70°F in late summer/early fall (often late August to early October, later toward the Gulf); annual bluegrass germinates as soils cool through the 70s into the 50s.

Annual bluegrass and winter broadleaf weeds sprout in fall and show up as bright green clumps in a dormant brown lawn in late winter.

Find pre-emergent herbicide, granular: DoMyOwn · Lowe's · The Home Depot · Amazon

Always follow the product label.

Retailer links are plain search links. We don't earn anything from them today; if we join a retailer's affiliate program later, we may earn a commission at no extra cost to you. Affiliate disclosure.

Post-emergent

Crabgrass and summer grassy weeds (post-emergent)

Late spring to early summer while plants are young (before tillering); generally not worth spraying after mid-July in the Midwest, when plants are large.

Broadleaf weeds in cool-season lawns (dandelion, clover, plantain, ground ivy)

Primary: early to mid-fall (September–November) while weeds are actively growing; secondary: late spring after full green-up.

Summer broadleaf weeds in warm-season lawns (clover, spurge, knotweed, lespedeza)

After full green-up, typically May to early June; avoid during spring green-up transition and during high heat.

Winter weeds in dormant warm-season lawns (henbit, chickweed, annual bluegrass)

Late fall through winter (about November to February) on mild days when weeds are actively growing; while warm-season grass is fully dormant.

Nutsedge (yellow and purple)

Early summer while plants are young and actively growing; a second treatment several weeks later if the label allows.

Fertilizer timing by grass

GrassSeasonWhenAvoid
St. AugustinegrasswarmSpring: About 2–3 weeks after full green-up (May in the Carolinas; earlier in Florida and south Texas)
Summer: Light feedings June–August where local rules allow
Last: No later than about mid-September in the Carolinas, about 6–8 weeks before first frost elsewhere		Feeding before green-up or late in fall (feeds weeds and favors large patch and cold injury).
BermudagrasswarmSpring: Several weeks after the lawn is fully green (April–May)
Summer: Every 4–6 weeks through mid-August (heaviest feeder of the group)
Late: Light, low-nitrogen/high-potassium feeding about 4 weeks before first frost, or skip		Heavy late-fall nitrogen (linked to spring dead spot).
ZoysiagrasswarmSpring: About 3 weeks after green-up
Summer: Late June/early July, optional again mid-August		Nitrogen in September–November (potassium only, per NC State).
CentipedegrasswarmSpring: Not before mid-May (NC State); after full green-up
Summer: Optional mid-summer feeding, especially on sandy coastal soils		Early-spring feeding, frequent feeding and liming unless a soil test calls for it (centipede decline).
BahiagrasswarmSpring: After green-up
Summer: Optional mid-summer feeding where local rules allow		Heavy feeding; yellowing on sandy soils is often iron, not nitrogen.
Tall fescuecoolEarly fall: September (main feeding)
Late fall: November, while still green
Late winter: Optional light feeding February–March		Feeding after mid-spring and through summer in the transition zone (stress and brown patch).
Kentucky bluegrasscoolEarly fall: Around Labor Day (late August–September)
Late fall: Late October–November, before the ground freezes
Late spring: Optional around Memorial Day		Early-spring and midsummer feeding (pushes top growth, favors crabgrass).
Perennial ryegrasscoolEarly fall: September
Late fall: October–November
Overseeded Bermuda: Light feeding once the winter rye is established, if needed		Summer feeding.
Fine fescues (creeping red, chewings, hard, sheep)coolEarly fall: September; often the only feeding neededFrequent or spring feeding; fine fescues thin out under high fertility.

Seeding and overseeding

Seeding/overseeding cool-season lawns (tall fescue, KBG, ryegrass, fine fescue)

Late summer to early fall: Start when daytime highs settle below about 85°F and 4-inch soil is about 50–65°F; finish at least 6–8 weeks before the 50% first fall frost.

Seeding/sprigging/sodding warm-season lawns

Late spring to early summer: After the last spring frost once 4-inch soil holds about 65–70°F; leave at least 60–90 days of growing season before first frost. St. Augustine is sod or plugs only.

Winter overseeding of dormant Bermudagrass with perennial ryegrass

Early to mid-fall: When 4-inch soil cools toward the low 70s°F and night temperatures drop into the 50s, usually a few weeks before the first frost.

Aeration and dethatching

Core aeration and dethatching, cool-season lawns

Early fall (with overseeding) is first choice; spring (March–May) second. Dethatch only if thatch is thicker than about 1/2 inch; tall fescue rarely needs it.

Core aeration and dethatching (vertical mowing), warm-season lawns

Late spring to midsummer, after full green-up (about late May–July). Vertical mow when thatch exceeds about 1/2 inch; Zoysia recovers slowly, so remove a little at a time. Never during dormancy or late fall.

Lawn regions

Sources

Summarized in our own words from public extension publications.