What Grows in Alta Sierra, California

The last hard freeze (28°F) in Alta Sierra typically lands around May 2, 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 May 23.

The first hard freeze (28°F) in Alta Sierra typically arrives around Nov 6, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 23, so the watching starts about Oct 7 — about 188 days after the spring freeze cleared.

Measured between 28°F hard freezes, Alta Sierra sees about 188 frost-free days — roughly May 2 through Nov 6, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 23 to Oct 23, about 153 days.

The federal record around Alta Sierra is a meaningful one — 95 documented sites, mostly Brownfields entries (62), the nearest Brownfields record about 1.6 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.

From about Oct 7 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 Nov 6 (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 Nov 6. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.