Winter vegetable gardening: It almost sounds like an oxymoron, like “open secret.” Well, here’s an open secret worth telling: Winter vegetable gardening is a real thing in the desert Southwest, deep South and Pacific Northwest. And it even has some bearing in the North.
What, are you kidding? Well, with the help of a hoop house and supplemental heat, Northern gardeners can grow tomatoes into December (some commercial operations do exactly that). And cold-hardy vegetables like spinach are a possibility, too — it can survive under a blanket of snow!
Kale is a root-hardy biennial. So while the top will die off eventually, the roots are alive and well and ready to burst into growth in spring. As for other vegetables, winter vegetable gardening pretty much requires a heated indoor space with supplemental lighting.
To see what you can grow, look up your area’s U.S. Department of Agriculture Plant Hardiness Zone. It will tell you the average low winter temperature for your region, a clue as to what will survive. Northern Florida is USDA Zone 9a, with a low of 20 to 25 F, meaning you can grow spinach and kale there all winter without protection. But Seattle is USDA Zone 8b, with a low of 15 to 20 F, so a hoop house might be necessary.
Cultural Considerations for a Winter Vegetable Garden
- Lighting. Full sun is imperative. While a little afternoon shade is helpful in many summer gardens, you need all the light and warmth you can get in a winter garden.
- Drainage. This applies to all seasons. Vegetables and herbs need a quick-draining soil. They don’t like “wet feet.”
- Soil. A good soil encourages faster growth and healthier plants — important factors in a winter garden, when a quicker harvest may be more imperative. Amend the soil with organic materials, such as compost and composted cow manure. You can also dig leaves into the soil adjacent to your planting rows; they’ll break down this year and the space will be ready for planting next year when you rotate your crops. Also, mulch with shredded leaves.
How to Plant Your Winter Vegetable Garden
Start by cleaning up the garden and removing fading summer crops. Pull them up by the roots and put them in the trash. Or, if your municipality offers a composting program, leave them on the curb for composting.
(Home composting is only advisable if you have a large pile that builds enough heat to destroy any pathogens in the debris. In most cases, it’s really not worth the risk.)
Timing is important. If you live in USDA Zones 9 and below, check the almanac or with your local cooperative extension to learn your area’s first average frost date. Work backwards from that date, figuring how many days it takes a plant to germinate (if growing from seed) and mature. The seed packet will have both those estimates. Then add in an extra couple of weeks because plants grow slower with less daylight available.
If you live in USDA Zones 10 or higher, frost is less of a worry. And no matter where you live, there are season-extending tricks that allow you to plant later in the season. One other note: Because the business end is protected by soil, root vegetables such as carrots, parsnips, radishes and beets have a longer harvest window if given some overhead protection.
- Seedlings. Seedlings, or starts, give you a leg up on the season. Depending on where you live, they may be hard to come by in fall. So you might have to start your own, then transplant into the garden.
- Seeds. Seeds are sold throughout the year. You even may have a ready supply left from spring. Larger seeds are usually sown directly in the garden, while smaller seeds are often started indoors in a soilless seed-starting mix. If sowing outdoors, do so as early in fall as possible, when the soil is still warm. This speeds germination.
- Transplanting. When transplanting seedlings to the garden, be sure to let them gradually acclimate to outdoor conditions. Put the seedlings in the shade for a few days, then part shade for a few days, then finally into full sun. Keep them well watered and protected from strong winds or heavy rains.
Psst! Learn how to winterize your vegetable garden for next year, too.
What Vegetables to Grow in Winter
- Hardy vegetables such as Brussels sprouts, cabbage, garlic, kale, mache, parsley, spinach and some varieties of lettuce can all recover from a hard freeze (25 to 28 F). However, they’ll do better with protection like cold frames or floating row covers (miniature hoop structures covered with fabric).
- Semi-hardy vegetables such as beets, broccoli, carrots, radishes, Swiss chard and most lettuces take light frost (29 to 32 F). In the case of broccoli, it will actually improve in taste because of the temperature swing.
- Warm-season vegetables such as tomatoes, peppers and okra can be grown in the warmest climates of the country. Even a light frost will kill them, and they won’t do well in temperatures below 50 F. You can grow them in USDA Zones 9 and above with overhead protection.
Winter Vegetable Garden Care
- Watering. While the scorching sun and unrelenting heat waves are gone, plants still need regular watering. Watering is recommended before an expected frost because moist soil freezes at a slower rate. As with watering at other times of year, you should water deeply and avoid wetting foliage in the evening so you don’t encourage foliar diseases.
- Protection. There are lots of ways to extend the season of your vegetable garden. One of the simplest is to grow plants in a container, which you can bring to shelter before a cold snap. Tomatoes, peppers, eggplant and many herbs do fine in containers. The larger, the better, because it allows room for root growth and won’t require watering as frequently.
- Other Season Extenders. A cold frame for a bed of smaller plants or a floating row cover for larger plants. One-gallon plastic milk jugs make inexpensive cloches — simply remove the bottoms and place over individual plants that need protection. It also speeds early growth of seedlings, acting as a miniature greenhouse. If space permits, invest in a plastic-covered hoop house or a greenhouse. Both capture heat during the day to help plants get through cold winter nights. However, supplemental heat will be necessary in most areas of the country.