Propagate by
seed
Germination temperature: 45 F to 85 F
- Will germinate at soil temperatures as low as 40 F.
Days to emergence: 4 to 7
Seed can be saved 5 years.
Most finicky of the cole (cabbage family) crops. Heads will not develop
properly in hot or dry weather, so timing is crucial. Will tolerate
cold as well as other cole crops in spring, but mature heads are not
resistant to hard freezes.Sow
seeds indoors 4 to 6 weeks before average last spring frost. Keep soil
warm (about 75 F), until germination. Then keep plants around 60 F.
Provide direct sun so plants don’t get leggy. When plants are 4 to 6
weeks old, transplant into garden 15 to 24 inches apart in rows 24 to
36 inches apart. Wait until soil temperature is 50 F or above and
danger of frost is past before transplanting.
Larger, older
transplants are more likely to bolt when exposed to cool temperatures
in the garden. Transplant when plants have four or five true leaves.
Some
cultivars will form small “button” heads when the weather turns warm
following a 10-day stretch when high temperatures only reach the 40s F.
Direct seeding is more difficult than with other cole crops,
especially in spring. For fall crops, plant seed in late-spring early
summer ½ to ¾ inch deep, about 3 inches apart. Thin to final spacings.
Or start transplants in late May and transplant in late June or early
July.
Plants have shallow root systems. Avoid even shallow
cultivation. Mulch to protect roots, reduce weed competition and
conserve moisture.
To preserve the white color of the curd, use
string or rubber bands to secure outside leaves over the head when it
is about 2 to 3 inches in diameter. From tying to harvest may take less
than a week in summer or as long as a month in fall.
Too much sun, heat or nitrogen fertilizer can cause “ricey” heads where the curd separates into small, rice-like grains.
Cabbageworms - Handpick and destroy. Row covers may be useful on small
plantings to help protect plants from early damage. Put in place at
planting and remove before temperatures get too hot in midsummer.Flea
beetles - Use row covers to help protect plants from early damage. Put
in place at planting and remove before temperatures get too hot in
midsummer. Control weeds.
Cabbage root maggot - White maggots
(larvae) attack all plants of the cabbage family. Larvae tunnel in and
feed on roots of plants. Damage causes wilting early on, death of
plants a little later on.
Cabbage aphids - A hard stream of water
can be used to remove aphids from plants. Wash off with water
occasionally as needed early in the day. Check for evidence of natural
enemies such as gray-brown or bloated parasitized aphids and the
presence of alligator-like larvae of lady beetles and lacewings.
Other pests:
Slugs and snails
Cutworms
Clubroot - Locate new plants in a part of the garden different from
previous year's location. If soil is infested, add lime to raise pH to
7.2Purple blotch (Alternaria porri)
- Avoid wetting foliage if possible. Water early in the day so
aboveground plant parts dry as quickly as possible. Avoid crowding
around plants; space apart to allow air circulation. Eliminate weeds
around plants and garden area to improve circulation. Practive
sanitation: when plants are not wet, carefully remove and destroy
affected plant parts. In autumn, rake and dispose of all fallen or
discarded leaves and fruit.
Other diseases:
Black rot
Black leg
Cabbage yellows
