Planting a fall garden

Who this is for

Gardeners anywhere frost ends the season, who want a second harvest from beds that held summer crops. Where frost is rare, cool-season crops are planted through fall and winter instead; see the regional notes.

Timing

Fall plantings are counted back from your typical first fall frost. The Frost dates page gives yours for any ZIP code: look up your frost dates.

To find the last good sowing date for a crop, count its days to maturity (and how long you want to harvest) back from the first frost, then allow about 2 more weeks, because growth slows as days shorten and cool ^[1][2]. Crops that frost kills, like beans and squash, need another 2 weeks so they finish before it ^[1]. A first frost date is a middle value: on that date the chance of frost is about 1 in 2, and two weeks earlier it’s about 1 in 10 ^[3].

The most common reason fall crops fail is planting them too late ^[2]. Midsummer heat is the other hurdle: lettuce and spinach sprout poorly in soil above about 70°F ^[2].

Checklist

1. Look up your first fall frost and count back from it. Frost dates by ZIP.
2. Note which plant families grew where before you pull them, so next year’s tomatoes and squash can move. Planning crop rotation.
3. In midsummer, start broccoli and cabbage in pots or a shaded seedbed, and sow carrots (below).
4. In late summer, sow greens and roots: lettuce, spinach, kale, radishes, and beets.
5. Around your first frost, plant garlic for next summer.
6. Sow a cover crop in beds you won’t replant. Cereal rye is the hardiest and can go in from late summer to mid-fall ^[14]; oats need 40–60 days before a killing frost and die over winter where winters are cold ^[15]. Sowing a cover crop.
7. Watch the forecast near your first frost, and cover tender plants on cold nights. Frost alerts.

By plant

Lettuce. Sow about 12–7 weeks before the first frost. Minnesota suggests about three months before it ^[6]. Hot soil can stop the seed from sprouting; a light mulch helps ^[10].

Spinach. Sow about 10–6 weeks before the first frost: Minnesota says about two months before it ^[7], and Purdue’s last good date is about 40 days before ^[3]. Spinach takes light frost and may overwinter ^[4].

Kale. Sow about 13–9 weeks before the first frost ^[8][3]. Kale and collards are the hardiest greens, to about 20°F ^[4]; collards need about 3 weeks longer than kale ^[3].

Radishes. Quick: about 25–30 days ^[5]. Sow a little at a time until about 4 weeks before the first frost ^[3]. They take hard frost ^[5].

Beets. Sow about 12–9 weeks before the first frost ^[3][10]. They survive the high 20s°F ^[4].

Carrots. Sow about 16–12 weeks before the first frost; sources agree on finishing about 12 weeks before it ^[9][10]. Where winters are mild, fall carrots can stay in the ground and be dug through winter ^[18].

Broccoli and cabbage. Set out transplants about 13–9 weeks before the first frost ^[10][3], from seedlings started about 6–8 weeks earlier ^[10]. Cabbage takes about 20°F; broccoli takes light frost ^[4].

Garlic. Plant cloves from about 3 weeks before to 2 weeks after the first frost. Northern sources plant after the first killing frost ^[11]; others plant a few weeks before the ground freezes ^[12]. The cloves need several weeks of cold to form bulbs ^[13].

Peas. Some sources sow fall peas about 10–8 weeks before the first frost ^[19], but they struggle where late summer stays hot, and Virginia’s guide doesn’t recommend them ^[20].