Vegetable Garden: Growing Cool-Season Vegetables
Fruits & Vegetables, Gardening Basics, Lawn and Garden by Julie Day
Though we tend to regard summer as the heyday for growing vegetables, cool-season crops in the spring and fall can be just as rewarding. The cool daytime temperatures and occasional light frost yield the sweetest, crispest, most flavorful vegetables around—stretching the summer bounty into an almost year-round smorgasbord.
Knowing When to Plant
- Cool-season vegetables thrive when daytime temperatures average between 65°- 80° F, with nighttime temperatures staying above 40° F. Spring and fall (and winter in some areas) provide perfect conditions for these crops.
- Most cool-season vegetables can tolerate a light frost and are generally planted 2-4 weeks before your last frost date in the spring.
- Since hot temperatures make these vegetables bitter, or cause them to go to seed, plan your growing seasons to avoid harvesting when the temperatures climb above 80° F.
- If you shop carefully, you can buy seeds or plants with detailed information about germination, proper planting times, and maturity for that particular variety. Armed with this information, and your average first and last frost dates, you can plan your fall and spring harvests for just the right time.
- If you live where the summers are cool, you can plant successive crops and harvest straight through until the first heavy freeze in the fall. If your summers are hot, follow up your cool-season crops with a summertime planting of warm-season veggies such as tomatoes, peppers, and cucumbers.
10 Easy-to-Grow Cool-Season Vegetables
Asparagus
Asparagus is a hardy, perennial vegetable that, once established, can produce crops for years. Most easily grown from year-old dormant roots, known as “crowns,” that should be planted as soon as the ground can be worked in early spring while crowns are still dormant. Be patient with asparagus, since it can take several years to become established. Plan on no harvest the first year, a very light crop (2-4 week season) the second year, and a full (6-8 week season) harvest on the third year.
Beets
Beets are best grown from seed planted a month before the last frost. Soil should be well-drained, rich, and aerated so it’s light, fluffy, and free of stones. Successive crops of beets can be planted all season long if temperatures are under 80° F. Begin harvesting beets when they are 1″ in diameter, and the greens at any time. Fall plantings of beets can be left in the ground and harvested as needed until the soil freezes. Radishes and turnips are more frost tolerant than beets and parsnips.
Broccoli
Broccoli is very cold hardy but will quickly “bolt” (go to seed) in hotter temperatures. It is most easily grown from transplanted seedlings set out about a month before the last frost in spring, or about two months before the first frost of fall. Different varieties have different maturation rates, so choose a variety likely to mature before the weather gets too hot in your area. Cauliflower is grown in a similar fashion but is both more heat and cold sensitive than broccoli and does best in the fall.
Cabbage
Cabbage likes rich soil with plenty of compost to feed the tender, tasty leaves. While cabbage can tolerate a light frost, it can go to seed if exposed to temperatures below 40° F for long periods of time. Plant seedlings about a month before the last frost in the spring, and continue planting and harvesting as long as temperatures stay between about 40° and 70° F. When you plant your cabbage, don’t forget to add in some kale, Swiss chard, and kohlrabi for good measure.
Carrots
Like beets, carrots need well-aerated, well-drained soil with no competition from weeds or other plants. Clay soil should be amended with lots of organic matter, but don’t use non-composted manure or fertilizers that are high in nitrogen. Keep the soil free of rocks to ensure well-shaped carrots, and protect from a hard freeze. Plant carrot seeds about 2-3 weeks before your last frost date in the spring. As you thin your carrot seedlings, enjoy the baby carrots in salads.
Lettuce
Lettuce thrives in cool, wet, spring weather and can be harvested by cutting leaves as needed. It can tolerate a light frost but should be covered or protected during a hard freeze. Use a cold frame to get a head start growing lettuce from seed in the spring, and add in some arugula, endive, and watercress to spruce up your salads. Thin your seedlings for larger heads and leaves, or leave them unthinned for smaller “baby” lettuce.
Onions
One of the hardiest of vegetables, onions can be planted as soon as the ground can be worked in the spring. Most easily grown from sets (partially-grown bulbs), onions form large bulbs according to the temperature and length of daylight. Long-day onions are recommended for northern climates, where the appropriate temperatures don’t arrive until the longer days closer to summer. Short-day onions are better for southern climates, where they can be grown during spring, fall, and winter.
Peas
Peas are another very hardy vegetable that can be planted in early spring, as soon as the soil can be worked. They can survive temperatures down to 25° F and even a light snow but don’t like hot weather. Zones 7 and warmer can grow peas as a winter crop, or plant seeds in the fall to germinate in early spring. Colder zones can plant seeds 1-2 months before the last frost. Like other legumes, peas absorb nitrogen from the air and shouldn’t be over-fertilized.
Potatoes
Technically known as tubers, potatoes are planted 2-4 weeks before the last frost in the spring. They are planted from “seed potatoes,” which are pieces of potato that contain at least one “eye” or sprouting bud. They like loose, well-drained soil with plenty of potassium, along with consistent moisture. Potatoes are semi-hardy and should be protected from a hard freeze. Mulch potatoes for insulation and to protect the tubers from sunlight, which causes them to turn green (and toxic!).
Spinach
Another very hardy vegetable, spinach should be planted as soon as the ground can be worked in early spring. It’s a fast grower and can be grown in succession plantings for a season of salad until hot weather. Like other leafy vegetables, it needs very fertile soil and plenty of water to produce tender leaves. Spinach will taste sweetest when nipped by cool weather, and fall crops planted during the summer may require overplanting to ensure that enough seeds germinate in the warm soil.
Whether you want to get a head start on planting in the spring or extend your gardening season in the fall, cool-season vegetables are the perfect solution.
Lettuce is a popular cool-season vegetable that’s easy to grow.
Further Information
- Eat Local (National Resources Defense Council) Searchable, state-by-state database giving the peak times for harvesting a variety of vegetables.
- Vegetable Planting Guide (Colorado State) Printable guide containing a chart listing seed germination temperature and time, planting space and depth, and harvest dates for various cool and warm season vegetables.
- Vegetable Garden: Planning and Layout Basic guide to starting a vegetable garden in your yard.
