Home / Guides / Vegetable Crop Calendars (A–C)
Vegetable Crop Calendars (A–C)Cool-Season Vegetable Calendar
Cool-season crops bookend the garden year. They start when the soil thaws and return when summer heat breaks, and the calendar is built from temperature, not dates.
Key points
- Plant cool-season crops when soil is workable, not by a set date.
- Heat ends the spring season, so count days to maturity.
- Count back from first fall frost for fall sowings.
- Shade and moisture help fall seeds germinate in warm soil.
What counts as a cool-season vegetable?
Cool-season crops grow best in mild weather and many tolerate light frost. Common examples include peas, spinach, lettuce, radishes, onions, turnips, rutabaga, parsnips and members of the cabbage family. Warm weather often causes them to bolt, turn bitter or stop producing.
Because they differ in tolerance, check each crop's guidance. A pea and a parsnip are both cool-season, but their timing and spacing look quite different.
Some crops sit between categories. Onions, for example, tolerate cool weather but need warmth later to bulb up, which is why they start early and finish in summer. Leafy crops such as lettuce and spinach germinate in cool soil but stall in heat, while root crops such as turnips and rutabagas size up best in the cooler weeks, so group your sowings by crop type when you plan.
When do you plant cool-season crops in spring?
As soon as soil can be worked. University of Maryland Extension says peas go in when soil reaches at least 40 degrees, and Utah State Extension advises parsnips two to three weeks before the last frost once soil is 40 degrees.
Use a soil thermometer and a squeeze test. If soil crumbles in your hand, it is ready. If it forms a muddy ball, wait.
Early crops also depend on the bed. Beds that drain well and face south warm sooner, and raised beds usually become workable earlier than low ground. Cold soil is a good time to prepare supports and mark rows, since the work is easier than when crops are growing.
How does heat end the spring season?
Iowa State Extension notes that summer heat makes radishes spongy, woody and hot and causes them to bolt. Missouri Extension warns that heat lowers pea quality and yield. Heat is the finish line for most cool-season crops.
Count the days to maturity for each crop and compare with when heat usually arrives. If it will not fit, choose an earlier variety or skip that crop in spring.
A worked example: if a pea variety needs about 60 days and heat usually arrives in early June in your area, you need to sow by early April. This is an example only, so use your own packet days and your own heat date.
When do you plant cool-season crops for fall?
Count back from your average first fall frost, using days to maturity and a margin. Iowa State Extension suggests radishes sown from early to mid-August through mid-September, and Missouri suggests August for fall peas, though Maryland says fall peas often struggle there.
Because these dates are regional, treat them as examples and use your own frost dates and local guidance.
A fall calendar is easier to build if you make a short list. For each crop write the packet days to maturity, add a margin and subtract from your first fall frost date. Keep seed for fall sowings cool and dry through summer so it stays viable, and write the purchase year on the packet.
How do you get seed to germinate in warm fall soil?
Late summer soil may be hot, which reduces germination for some crops. Keep the seedbed moist, shade it with cloth or a board, and sow slightly deeper where recommended.
Parsnip guidance from Utah State notes that soil above about 80 degrees reduces germination, so be mindful of soil temperature at sowing.
Seeds of lettuce and spinach germinate poorly in hot soil, so some gardeners chill seed in a refrigerator for a short time or sow in the evening. Ask extension for local techniques.
How do you protect and extend the harvest?
Row covers, cold frames and mulch extend picking into late fall and winter. Many cool-season crops, such as parsnips, turn sweeter after cold weather, and Utah State notes frost improves flavor.
Be ready for a hard freeze, which can damage even hardy crops. Harvest tender items ahead of it.
Cold frames and row covers keep greens producing long after open beds have quit, though they need ventilating on warm days. Mulch also keeps soil from freezing and thawing repeatedly, which can heave shallow-rooted seedlings out of the ground.
How do you use succession and rotation?
Fast crops like radishes can be sown every 7 to 10 days, according to Iowa State. Slower crops need a single, well-timed planting.
Rotate plant families so that cabbage-family crops do not follow each other. Keep notes to refine your own calendar.
At the end of each cool season, pull spent plants and note what worked. A short log for each crop gives you a calendar tuned to your own garden.
Sources and further reading
Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.