What Grows in Sierra Vista, Arizona

The last hard freeze (28°F) in Sierra Vista typically lands around Feb 18, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Mar 11.

The first hard freeze (28°F) in Sierra Vista typically arrives around Dec 5, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 21, so the watching starts about Nov 5 — about 290 days after the spring freeze cleared.

Measured between 28°F hard freezes, Sierra Vista sees about 290 frost-free days — roughly Feb 18 through Dec 5, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 11 to Nov 21, about 255 days.

The federal record around Sierra Vista runs heavier than most — 167 documented sites, mostly Underground Storage Tanks entries (74), the nearest Nitrate record about 0.2 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.

From about Nov 5 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Dec 5 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Dec 5. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.