Garden Yardstick

Cool-Season vs. Warm-Season Vegetables

Updated October 16, 2026

Vegetables fall into two broad groups. Cool-season crops such as peas, lettuce and broccoli grow best in the mild weather of spring and fall and tolerate frost. Warm-season crops such as tomatoes, beans and squash need warm soil and frost-free weather. Knowing which group a crop belongs to tells you when to plant it.

Every date below counts from your average last spring frost. Look yours up with Frost Dates by ZIP Code.

The four groups

Extension services usually split vegetables into four groups by how much cold they can take.

Group Examples When to plant
Hardy Peas, spinach, kale, cabbage, broccoli, onions, garlic, radishes, turnips 4–6 weeks before last frost
Semi-hardy Lettuce, carrots, beets, chard, potatoes, cauliflower 2–4 weeks before last frost
Tender Beans, sweet corn, tomatoes, cucumbers, summer squash On or after the last frost
Very tender Peppers, eggplant, melons, okra, sweet potatoes 2–3 weeks after last frost, in warm soil

Hardy crops survive hard frosts in the 20s once established. Semi-hardy crops handle a light frost. Tender crops are killed by frost. Very tender crops are damaged by cold even without frost and need soil of 65°F or more to grow well.

Cool-season vegetables

Cool-season crops grow best when days are in the 60s and low 70s °F. In heat, many of them turn bitter or bolt: they send up a flower stalk and stop producing leaves.

  • Plant early. Sow peas and spinach as soon as the soil can be worked in spring.
  • Harvest before heat. Pick lettuce and spinach before summer heat makes them bitter. Choose slow-bolting varieties for late spring.
  • Plant again for fall. Many cool-season crops taste best in fall, when cool nights sweeten kale, carrots and cabbage. See Planting a Fall Garden.
  • Use shade. In warm regions, afternoon shade or shade cloth stretches the lettuce season.

Warm-season vegetables

Warm-season crops grow best when days are in the upper 70s and 80s °F and nights stay above 50°F. Planted into cold soil they sit and sulk, and seeds may rot before they sprout.

  • Wait for warm soil. Beans and corn need soil of about 60°F to germinate well; squash, cucumbers and melons prefer 65 to 70°F.
  • Start slow growers indoors. Tomatoes, peppers and eggplant need a head start indoors in most of the country. The Seed Starting Calculator gives the dates.
  • Sow fast growers directly. Beans, corn, squash and cucumbers grow quickly from seed sown in the garden after the last frost.
  • Watch for extreme heat. Tomatoes and peppers drop flowers when days stay above about 90°F, so in the hottest regions they are planted early in spring and again in late summer.

Putting it together: a spring sequence

With a last frost date of April 20, a typical spring planting order is:

When What to plant
Early to mid March Peas, spinach, onion sets, radishes
Late March to early April Lettuce, carrots, beets, potatoes, broccoli and cabbage transplants
Late April Bush beans, sweet corn, summer squash seed
Late April to early May Tomato, cucumber and basil transplants
Early to mid May Peppers, eggplant, melons

Shift every date by the difference between April 20 and your own frost date.

Where you live changes the calendar

  • In the North, spring and fall blur into one long cool season with a short, warm summer. Choose quick-maturing varieties of warm-season crops.
  • In the South and Southwest, cool-season crops are often grown through fall and winter, and summer is too hot for lettuce and peas entirely.
  • On the West Coast, mild summers suit cool-season crops for much of the year, while tomatoes and peppers can struggle near the ocean.

Quick rule

If a crop’s seed packet says “sow as soon as soil can be worked,” it is cool-season. If it says “after all danger of frost has passed,” it is warm-season.

Tools for this