Mainstay Vegetables: Cabbage
Cabbages, ready to thin to 1-ft apart
Cabbages grow best at temperatures of 60 to 65 °F. They are cool-season vegetables that are grown in early spring or fall.
Cabbage transplants are best for spring plantings: you can start them indoors. When planted in the spring, cabbages need to be planted early enough that they can be harvested before the weather gets too hot.
Fall plantings may be directly seeded into the garden. Loamy to sandy soil is best for direct seeding. It is critical to keep the soil moist during seedling establishment, and we've had good success with drip irrigation plus mulching. They should be planted in an area that is protected from the wind . Direct-seeded plantings should be thinned to the desired spacing when the plants are at the three-leaf stage – and remember, these immature plants are GREAT in salads..They will last a while: in the fall, mature cabbages can handle temperatures as low as 18 to 20 °F.
Plant spacing really affects head size. For 2- to 3-pound heads, you need to transplant plants or space seed 9 to 12 inches apart. Varieties for sauerkraut are supposed to be spaced at least 12 inches apart.
Several worms (imported cabbageworm, cabbage looper, diamondback moth caterpillar), harlequin bugs, cabbage maggots, aphids and flea beetles are the major insect problems. You can make most of them disappear like magic by using something called Bt: bacillus thuringiensis. Mix it with water and spray it on the cabbages once a week. It's used by organic growers, and causes any worms, caterpillars or larvae to die but is harmless to humans.
There are also companion plants you can use to keep insects out of your cabbages.: Celery, dill, onions and potatoes are good companion plants. Celery is said to improve cabbage growth and health. White clover interplanted with cabbage has been shown to reduce the native cabbage aphid and cabbageworm populations by interfering with the colonization of the pests and increasing the number of predatory ground beetles. If you plant chamomile with cabbage, it Improves growth and flavor. However, cabbage does not get along with anything else in the nightshade family (tomatoes, eggplants), peppers, strawberries, grapes, lettuce or pole beans.
Just like with over watering tomatoes, head cracking or splitting can happen if you water cabbages too much right before harvest. (They say you can root-prune the nearby soil with a spade or trowel to reduce water uptake, but our area is so dry I never bother.)
Of cabbage diseases, Black Rot causes the most serious damage. It appears as V-shaped lesions down the leaves and spreads into the water conducting system of the plant. Black rot is caused by a bacterium that is seed-borne or that can be transmitted by transplants. Warm, moist weather favors the disease. There is no control for black rot once it is established in a planting. Prevent black rot by purchasing transplants that are marked with a tag indicating that they are certified disease-free. Should a bed have this disease solarize the soil to kill all organisms.
Note: Unlike lettuce, which bolts when it gets too hot, cabbages will "bolt" (produce a flower stalk and get tough and bitter) if, after a following a good growing period, they exposed to 10 or more continuous cold days between 35 and 50 °F.
This year we followed the local agricultural cooperative extension's advice as to local cultivars, and have had great success with the Savoy Express variety.