Many climate zones in the United States and elsewhere are conducive to growing vegetables in the winter. Although tomatoes, cucumbers, eggplant, green beans, peppers and other warm season crops will not survive temperatures below about 40 degrees Fahrenheit, many types of vegetables are well suited to cooler temperatures. If your soil usually freezes solid during winter, however, you must grow your winter vegetables in a protected environment such as a greenhouse.
The “Saga” variety of broccoli has been proven to be cold tolerant, according to OrganicGardening.com. Ohio State University advises to set out young broccoli plants in July for late fall and winter harvest.
Broccoli needs rich soil that is well drained with lots of organic ingredients. The soil’s pH should be slightly acidic, with a reading between 6.0 and 7.0. Space plants 18 inches apart in rows two feet apart. Fertilize young broccoli plants with an all-purpose plant food having an N-P-K ratio of 20-20-20 when you set them out, following label instructions.
Swiss chard is a good tasting, hardy biennial leaf vegetable that will grow all winter from your spring planting. The “Ruby Red” variety of Swiss chard is cold tolerant, according to OrganicGardening.com. Chard needs rich soil that has a neutral to slightly alkaline pH between 6.5 and 8.5. GardeningPatch.com advises to plant chard seeds in spring directly into the soil.
Scatter seeds on top of the soil and then barely cover with more soil. Make your rows two feet apart. Thin seedlings to about 10 or 12 inches apart. If your soil is rich with compost and other organic materials, you needn’t fertilize chard. Harvest individual leaves by pinching or snipping them off at their base. Chard will bolt to seed during its second spring or summer in the ground.
The “Nandor” variety of carrot is one of the most cold tolerant varieties of this vegetable, according to OrganicGardening.com. Mother Earth News reports that if you plant carrot seeds directly into the ground in fall before your first frost, this vegetable will give you a winter harvest.
Carrots need fertile, well-drained, non-rocky soil. Sow seeds by scattering them on the soil surface or in a narrow trench and then cover them with ¼ inch of soil. Make your rows about one foot apart and then thin seedlings to about four inches apart when they are about two inches tall.
The "Winter Density" and "Green Wave" varieties of lettuce are the most cold tolerant, according to Organic Gardening.com. Garden of Eden advises to plant lettuce seeds for winter harvest beginning in August and continuing through November. Lettuce needs well-drained soil and a sheltered, sunny location. Sow seeds thinly and cover with about ½ inch of soil. Leave about one foot of space between your rows. You can stagger your harvest by planting more seeds every four weeks.
When plants are two inches tall, thin them to stand six to 12 inches apart. If very cold weather is forecast, you can protect your lettuce plants by covering them with floating row cover or cloches, which are glass or plastic "bell jars" you set over plants.