What to Plant in September — Zone 3

September closes the season in zone 3 — the average first frost arrives around Sep 20. It's harvest and garlic-planting time more than sowing time.

Fall planting — Counted back from the first fall frost.

🧄 Garlic Aug 9 – Sep 6 plant cloves; harvest next summer

Windows use zone 3's typical frost dates (May 15 / Sep 20). For your own city's dates, run the frost lookup — the planting calendar then localizes everything automatically.

Frequently asked questions

What can I plant outside in September in zone 3?

1 crops can go in the ground: garlic. Exact windows are in the tables above — early and late in the month can differ by a full frost date.

Is September the right time for tomatoes in zone 3?

The spring window has passed; tomatoes set out this late won't beat the Sep 20 average first frost to ripeness. Plan for next spring's seed-starting instead.

September in other zones

Zone 1Zone 2Zone 3Zone 4Zone 5Zone 6Zone 7Zone 8Zone 9Zone 10Zone 11Zone 12Zone 13

Zone 3, month by month

← August October → All months