Two families of crops
Cool-season crops grow best in mild weather, roughly when days are in the 60s and 70s °F. Many of them tolerate frost, and some taste sweeter after one. They include most leafy greens, the cabbage family, peas, and many root crops. In hot weather they tend to bolt (run to flower), turn bitter or simply stop growing.
Warm-season crops need warm soil to germinate and warm nights to grow and set fruit. Frost damages or kills them. They include tomatoes, peppers, eggplant, beans, corn, squash, cucumbers and melons. Planted too early into cold soil, they sit and sulk, and seeds can rot before they sprout.
Within each family there is a range. Our crop table groups everything into three frost-tolerance levels:
- Hardy crops take frost and short dips into the 20s °F once they are hardened off. They can be planted out several weeks before your last spring frost.
- Half-hardy crops handle a light frost but can be damaged by a hard freeze. Plant around your last frost date.
- Tender crops are damaged by frost. Plant them out after your last frost, once the soil has warmed.
The crops, grouped
From our crop table, which also drives the planting calendar:
| Hardy | Half-hardy | Tender |
|---|---|---|
| Broccoli, Cabbage, Brussels sprouts, Kale, Collards, Spinach, Arugula, Peas, Radish, Turnip, Kohlrabi, Onion (from seed), Leek, Garlic | Cauliflower, Lettuce, Swiss chard, Carrot, Beet, Potato, Cilantro, Parsley, Dill | Tomato, Pepper, Eggplant, Bush beans, Pole beans, Sweet corn, Cucumber, Summer squash, Winter squash, Pumpkin, Melon, Watermelon, Okra, Sweet potato, Basil |
A season in four waves
1. Early spring: hardy crops, about 4–6 weeks before last frost
As soon as the soil can be worked, meaning it crumbles in your hand rather than forming a sticky ball, sow peas, spinach, radishes and arugula, and set out hardened-off transplants of broccoli, cabbage, kale and onions. These crops get most of their growing done before summer heat arrives. If a hard freeze is forecast just after planting, a layer of row cover is enough protection for most of them.
2. Around last frost: half-hardy crops
Lettuce, carrots, beets, chard, cilantro, potatoes and cauliflower go in around your average last frost date. They can handle a light frost but appreciate cover if a cold snap is forecast.
3. After last frost and once soil warms: tender crops
This is the big planting of the year. Our table lists tomatoes going out one to three weeks after last frost, and peppers, eggplant, melons and okra later still, because they need warmer soil and nights. Beans, corn, squash and cucumbers are usually sown directly once the soil is warm enough (see soil temperature for planting). Sweet potatoes go in last.
Gardeners in cold areas often wait for the safer “10% risk” last-frost date, the date after which a frost is expected only about one year in ten, rather than the median. Your ZIP page shows both.
4. Late summer: the second cool season
Counting back from your first fall frost, many cool-season crops can be planted again in mid to late summer for a fall harvest. In many regions fall broccoli, cabbage and carrots do better than spring ones, because they mature into cooling weather instead of heat. See planning a fall garden.
Hot-summer and mild-winter regions
The four-wave pattern assumes a cold winter and a warm summer. In much of the Deep South, Texas, Florida and the low desert Southwest, it shifts:
- Summer can be too hot for even some warm-season crops to set fruit. Tomatoes and peppers often stop setting fruit in very hot weather and pick up again as it cools.
- The main season for cool-season crops is fall through spring, not spring through fall. Lettuce, spinach and peas often fail if sown in late spring.
- Where frost is rare, our frost-date tools will say so. Your local Cooperative Extension service publishes calendars for your area, and they are the best guide in these climates.
Why not just plant everything after last frost?
You could, but you would lose the best weeks for cool-season crops. By the time tomatoes can go out, spring is already warming toward the heat that makes spinach bolt and lettuce bitter. Using the hardy-crop window before last frost effectively gives you an extra season from the same beds. Many of those beds are free again by the time the warm-season crops need them, or can be used for a fall crop later.
Succession and spacing
- Fast crops in between: radishes, arugula and lettuce mature quickly and fit in gaps, for example between young squash plants that will fill in later.
- Stagger sowings: sowing a short row of lettuce, beans or carrots every two to three weeks gives a steady harvest instead of a glut.
- Follow heavy feeders such as corn and squash with something lighter, or add compost before the next crop.
Turning this into dates
All of this is relative to your frost dates. Enter your ZIP on the home page for your last and first frost and a list of what to plant this week, or open the planting calendar for a full year. The crop timing guide has the week-by-week offsets for every crop.
Related
- Soil temperature for planting
- Planning a fall garden
- Protecting plants from late frost
- How frost dates work
- Frost dates for your ZIP
Written for SowByZip. Last reviewed 2026-10-20. See about this site for how pages are made.