Cool- and Warm-Season Vegetables
On this page, find information about selecting, inspecting, choosing, and planting vegetable seeds and plants, including:
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- The differences between cool-season and warm-season vegetables and when to plant them.
- Frost tolerance differences between the two classes of vegetables, cool-season and warm-season.
- How differences between vegetable growth, production and maturity traits make sequential planting and double-planting possible.
- How to use season-extension and early-start planting techniques to grow more vegetables in your home vegetable garden.
- The importance of prompt planting of nursery vegetable starts.
Two Classes of Vegetables
Learn the two main classes of vegetables and how they differ. Make key choices, and decide to plant with seed or nursery starts.
Cool-Season Vegetables
Vegetables that germinate quickly and tolerate cool soils and early-spring conditions are called cool-season vegetables.
They include such popular plants as asparagus, beets, cabbage and its many close relatives. Carrots, celery, many lettuce varieties, leeks, mustard, onions, peas, potatoes, and spinach are also cool-season vegetables.
Some cool-season vegetables are very cold hardy and tolerate even hard frosts once they become established. Others can take brief periods of cool temperatures or light frosts but need protection to prevent their foliage from freezing.
Warm-Season Vegetables
Edible plants with large, starchy seeds that take a week or more to germinate and prefer both warm soils and mild to warm air temperatures are in a class called warm-season vegetables.
They include amaranth, various beans, corn, cucumber, eggplant, gourds, melons, peppers, squash, and tomato.
Planted in too-cool soil, they will fail because of fungal diseases or will struggle to become established.
Selecting Vegetables
These cool-season and warm-season groups give gardeners many choice when selecting plants to grow.
Mixing groups allows you to plant a succession of crops in your garden.
For example, first plant cool-season vegetables as soon as the soil becomes workable in spring and frost hazard passes. While they grow and mature, sow a second or even a third planting, giving three crops from the same patch of soil.
For another approach, plant fast-growing vegetables side by side with other plants that have long maturity cycles.
The quick-to-harvest plants will be picked and eaten by the time the longer-maturing varieties need their space to spread out.
Use the charts and tips found in this section to choose vegetables for your garden.
Give the cool-season vegetables an extra-early start by sowing them indoors in bedding trays or individual pots. Repeat the process for your warm-season vegetables: Plant them about 3–4 weeks before air temperatures rise above 60°F (16°C) and consistently stay there through the evening hours.
In autumn, when temperatures during nighttime cool, extend the season further by covering plants in the evening to prevent cold dew and frost from forming.
Getting your plantings off to a good start and extending the season are valuable for getting more growing time and the best ways to assure you’ll have large, tasty harvests later in the season.
Prompt Planting
When faced with the many choices of vegetable starts and seeds in a garden store or nursery, it’s tempting to purchase all the plants you’ll need in a single trip. That can be a mistake.
Transplants were reared in grower nurseries and arrive in peak condition, ready to transplant into your garden. While seeds can wait until conditions are right, transplants must be planted as soon as possible.
If necessary, remove transplants from their grower containers and heel the starts’ roots into temporary beds until they can be planted and spaced properly, or transplant them to a larger container for short holds.