What can I plant in September in zone 12a?

In USDA hardiness zone 12a (last spring frost around Jan 26, 2026, first fall frost around Jan 24, 2026), September is a good time to direct sow outside annual ryegrass, crimson clover, hairy vetch, rye.

What to plant in September in zone 12a

4 crops to start indoors, direct sow, transplant, or harvest in September in USDA hardiness zone 12a. Typical last spring frost around Jan 26, 2026, first fall frost around Jan 24, 2026 — exact dates vary by location within the zone.

Want exact September dates for your address in zone 12a, a drag-and-drop bed layout, and sowing reminders? Enter your ZIP:

Or get a printable zone 12a calendar and reminders by email:

Direct sow outside

Sow these straight into the garden bed this month.

Annual Ryegrass
Crimson Clover
Hairy Vetch
Rye

Keep going

Full zone 12a planting calendar →
What to plant in September (all zones) →
Succession planting for a continuous harvest →

Timings use NOAA 1991–2020 climate normals for a representative location (Wahiawa, HI) in zone 12a, computed with the same engine as GardenDraft’s in-app schedule. Guidance, not guarantees — your exact dates depend on your address.