Arizona Lawn Care Calendar 2026: Fall & Spring Task Dates
Every lawn and garden task dated to Arizona's frost calendar and live soil temperature: warm-season grasses, extension-service timing.
Next up in Arizona: overseed, window open through October 25The Arizona fall lawn season at a glance
Live · soil temp updates hourlyPhoenix does the most famous overseed in America: bermuda is scalped and sown with perennial ryegrass each October once nights drop below 65°F, giving a green winter lawn that the bermuda reclaims in May.
What to do in Arizona right now
Tasks whose window is open or opening within three weeks, checked against live soil temperature at Phoenix (live reading unavailable, calendar only). Enter your ZIP for your own soil reading.
Overseed
Do it nowInside the typical window (October 1 – October 25) (ryegrass for winter color only — do not seed bermuda or zoysia now).
How to overseedCover crop / winter rye
Do it nowInside the typical window (October 4 – November 8).
Covers all 50 states. Windows are frost-date typicals; live soil temperature adjusts the soil-gated tasks.
Arizona fall lawn & garden calendar
| Task | Typical window | Status | Why now |
|---|---|---|---|
| Fall pre-emergent | September 1 to October 1 | Done for the year | Stops winter annual weeds — annual bluegrass (Poa annua), henbit, chickweed — from germinating as soil cools through 70°F. |
| Bring houseplants in | November 1 to November 14 | Later | Tropical houseplants are damaged by nights in the 40s, well before any frost — and a sudden move from 50°F nights to a 70°F house causes leaf drop. |
| Core aerate | April 26 to June 10 | Done for the year | Relieves compaction and opens thatch so water, air, and fertilizer reach the roots — and it is the best seedbed prep for overseeding. |
| Overseed | October 1 to October 25 | Do it now | Warm soil plus cool air is the best germination combination of the year, and new seedlings need 6–8 weeks of growth before the first hard freeze. |
| Cover crop / winter rye | October 4 to November 8 | Do it now | A cover crop holds soil, scavenges leftover nitrogen, and adds organic matter over winter — bare vegetable beds lose both soil and fertility to winter rain. |
| Fall fertilizer | August 1 to August 31 | Done for the year | Fall nitrogen builds roots and carbohydrate reserves instead of top growth — the single most valuable feeding of the year for cool-season turf. |
| Plant garlic | November 1 to December 6 | Later | Garlic needs 4–6 weeks to root before the ground freezes but should not push much top growth — planting around the first frost, 2 weeks either side, is the sweet spot. |
| Final mow | November 8 to December 6 | Later | Grass left long under snow mats and invites snow mold; cut too short it loses winter insulation. The last cut at 2–2.5 inches is the compromise. |
| Winterize sprinklers | November 12 to December 6 | Later | Water left in lines and backflow preventers expands when it freezes and splits pipes, valves, and heads — a repair that costs more than the whole winterization. |
| Plant tulips & bulbs | November 29 to January 10 | Later | Bulbs root in cool soil and need 12–14 weeks of chilling below 45°F to flower — planted into warm soil they rot or sprout early. |
Arizona spring lawn calendar
Spring runs off the last frost (February 25) and, for pre-emergent, off soil temperature. The crabgrass trigger is 55°F at 1 to 2 inches for four or five days, not a date.
| Task | Typical window | Why then |
|---|---|---|
| Spring pre-emergent | January 21 to February 18 | Crabgrass germinates when soil at 1–2 inches holds 55°F for 4–5 consecutive days. Pre-emergent has to be in place BEFORE that — it has no effect on crabgrass that has already sprouted. |
| First mow | February 18 to March 18 | The first cut removes winter-damaged tips and signals the lawn to tiller and thicken — but mowing soggy soil ruts it, and scalping stresses turf before roots are working. |
| Spring grass seed | April 8 to May 20 | Spring seeding is second-best (fall is better) because seedlings face summer heat and crabgrass, but it is the only window for warm-season seed, which needs 65–70°F soil. |
| First spring fertilizer | April 8 to May 6 | Feeding too early pushes leaf growth ahead of root growth and feeds weeds — wait until the lawn is actively growing and has been mowed 2–3 times (cool-season) or is fully green (warm-season). |
Soil temperature and frost countdown across Arizona
| City | Soil temp now (6 cm) | Typical first frost | Days to first frost | Typical last frost |
|---|---|---|---|---|
| Phoenix | loading… | December 12 | 64 | February 2 |
| Tucson | loading… | November 26 | 48 | February 22 |
| Flagstaff | loading… | September 26 | passed | June 6 |
Soil temperature is modeled at 6 cm by Open-Meteo and read live in your browser; frost dates are NOAA 1991 to 2020 normals for each reference station.
Arizona lawn grasses and mowing heights
Arizona is a warm-season state. Common lawn grasses: Bermudagrass (overseeded with ryegrass in winter), St. Augustine, buffalograss (Flagstaff). Warm-season grasses grow from late spring to early fall, go straw-brown dormant at the first frost, and are never seeded in fall, only overseeded with ryegrass for winter color.
| Grass | Mowing height |
|---|---|
| Bermudagrass | 1 to 2 in |
| Zoysia | 1 to 2.5 in |
| St. Augustine | 3 to 4 in |
| Centipede | 1.5 to 2 in |
| Bahiagrass | 3 to 4 in |
Task-by-task guide for Arizona
Soil temperature, growing degree days, and the frost anchor
Soil temperature beats air temperature. Grass seed germinates from about 50°F soil, crabgrass from a sustained 55°F, warm-season seed from 65°F, and tulips want soil under 55°F so they root without sprouting. Soil at seed depth warms and cools far more slowly than the air above it, so a hot week in April or a cold snap in October moves the soil only a few degrees. That is why the soil-gated tasks on this page defer to the live reading over the calendar.
Growing degree days (GDD) are how turf scientists track it: daily heat accumulated above a base (usually 50°F). Crabgrass germination, for instance, lines up with roughly 200 GDD base 50°F in spring, the same signal as forsythia finishing bloom. The frost calendar is the long-run average of all that heat accounting.
Why first frost anchors the fall. Most fall tasks are really a countdown to the first hard freeze: seedlings need 6 to 8 weeks of growth before it, garlic needs 4 to 6 weeks of rooting, cool-season fertilizer needs 2 to 4 weeks of uptake, and irrigation has to be drained before it. (Warm-season fertilizer is the exception: Southern extension programs cut nitrogen off on a calendar date, not a frost offset, because the Deep South frost arrives long after the grass stops growing.) Arizona's typical first frost is November 15; see the Arizona frost dates page for the early/late brackets and city table.
Arizona lawn care FAQ
The rest of your Arizona fall
More Southwest lawn calendars
Windows are climatological typicals computed from NOAA 1991 to 2020 frost normals and grass-zone rules, cross-checked against University of Arizona Cooperative Extension guidance. Any single year runs ±2 weeks; live soil temperature (Open-Meteo, 6 cm) is modeled, not measured. National tool: fall planting calendar by ZIP → Hero image: “2022-10-26 08 11 53 Fallen Red Maple and Saucer Magnolia leaves on a lawn in autumn along Aquetong Lane in the Mountainview section of Ewing Township, Mercer County, New Jersey” by Famartin, CC BY-SA 4.0