Know Before You Grow: Cabbage and Kale (2024)

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Choosing a Variety

When you're deciding what variety of cabbage or kale to plant in your garden, your decision will be mainly based on your taste and storage needs. Large-headed late cabbages usually store well and are good for cooking, proving especially appropriate for turning into sauerkraut. Savoy and conical types are more tender and therefore good for slaws and salads, while Chinese cabbage is heat tolerant and quite versatile—it's delicious cooked or raw. As far as choosing a kale, green ones tend to be sweeter while red varieties are somewhat more appealing to the eye. Red kale also contains anthocyanins, an antioxidant.

When to Start Cabbage & Kale Seeds

Cabbage seeds are best started indoors 8 to 10 weeks before the last frost, at a temperature of 70 to 75°F. If you want a fall crop, sow outdoors in midsummer. In Zone 8 and warmer, if you want a winter crop of cabbage, sow outside in early fall.

Expect germination in 10 to 14 days.

How to Start Cabbage & Kale Seeds

Sow your cabbage seeds at a depth of 4 times the size of the seed, or ½ inch deep, in a sterile starting mix and water thoroughly. Once the seeds have sprouted, be sure to keep the soil lightly moist, and feed them with a liquid fertilizer at half strength every two weeks.

Make sure the plants receive plenty of light—fluorescent light for around 14 to 16 hours a day is also ideal for the fastest growth. You will want to keep the seedlings just a few inches below the light so they don't “stretch” and get “leggy." If you don't have fluorescent lighting, a south-facing window will do just fine.

Chinese cabbage and kale do well direct sown into the garden. In cool-weather climates, other cabbages can be started outdoors as well, up to four weeks before the last frost date. If you want a fall crop, sow seeds in midsummer.

To conserve seeds, group 3 or 4 together at the desired plant spacing instead of the traditional method of sowing in continuous rows. Water well and make sure the topsoil stays moist, especially if planting during the drier midsummer. Once your seedlings have reached several inches and have at least two sets of true leaves, pull up all but the strongest one in each group.

Harvest is usually within 50 to 90 days from sowing, depending on the variety.

Planting Out

Once the seedlings have two sets of true leaves, you'll need to start the “hardening off” process. Do this by setting them outdoors in a lightly shaded area for an hour or two. The next day, give them a longer visit outside until they remain outdoors overnight, still in their pots. Naturally, if a cold spell hits, bring them indoors again to wait for the temperature to rise.

Plant out as soon as the soil can be worked in spring, setting the plants at least 8 inches apart, in rows spaced 24 to 36 inches apart. (Exact spacing depends on the mature size of the plant.) Site your cabbages in full sun in a rich, fertile, moist, well-drained soil, and feed them with 5-10-5 (or higher) fertilizer or nitrate of soda. Fertilize when first planting out and then every 4 weeks.

Special Considerations

• To avoid cutworm damage, place a tuna fish or cat food can (with top and bottom removed) around the young plant, buried halfway into the soil.
  
• Cabbage can be harvested anytime after the heads form. Just be sure to cut them when they are solid (firm to the touch) but before they split or crack.
  
• Be very careful when weeding as cabbage roots are easily damaged by cultivation. If you fear the roots could be damaged by the removal of a large weed, clip it off instead of pulling it out.
  
• Carrots, lettuce, onions, and spinach are all good companions to cabbage.
  
• Dark green, leafy cabbages contain a lot of Vitamin C, iron, and folate. Cabbage is also a good source of beta-carotene, potassium, and phytochemicals (plant-derived chemical compounds that are non-essential nutrients but still considered to be important to human health), such as glucosinolates, which are believed to help prevent lung cancer.
  
• Don't overcook your cabbage, as this reduces its nutritional content.

Growing Tips for Cabbage & Kale

• Cabbage and kale prefer cool weather and can tolerate light frosts.
• They perform best in full sun in moist, well-drained soil that is rich with plenty of organic material.
• If you can avoid it, do not plant cabbage or kale where they or other members of the cabbage family were previously grown—rotate the growing areas. Members of the cabbage family include broccoli, cauliflower, kohlrabi, Brussels sprouts, mustard, and rapini. They are all susceptible to the same diseases, which can be passed through the soil from year to year.
• It's important to keep your plants moist, but it's especially important for crops that are started in summer.
• Mulch your cabbage and kale with up to 2 inches of organic material, being sure to keep the mulch about an inch away from the stem. This will keep the soil moist, control weeds, and provide some food for the plants.

Pests and Problems to Watch For

Aphids and cabbage loopers are some of the most common pests you will find bothering your cabbage and kale.

• Cabbage loopers are the caterpillar stage of a type of nocturnal moth, and their name comes from the way they arch their bodies as they crawl, inchworm style. They're very destructive to plants, as they have a voracious appetite for leaves. Covering the plants with screening or a row cover can prevent the presence of these pests.
  
• Aphids are often found on the underside of leaves and on stems and young buds. You can wash them off with a strong stream of water or use an insecticidal soap (be sure to follow the label instructions). Check the plants regularly, as aphids can be a recurring problem.

Rotate your crops to avoid soil-borne diseases.

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