What Grows in San Juan, Texas

The last hard freeze (28°F) in San Juan typically lands around Jan 16, 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 Feb 6.

The first hard freeze (28°F) in San Juan typically arrives around Dec 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 9, so the watching starts about Nov 23 — about 341 days after the spring freeze cleared.

Measured between 28°F hard freezes, San Juan sees about 341 frost-free days — roughly Jan 16 through Dec 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 6 to Dec 9, about 306 days.

The federal record around San Juan is a meaningful one — 830 documented sites, mostly Underground Storage Tanks entries (634), the nearest Underground Storage Tanks record about 0.2 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 Nov 23 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 23 (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 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.