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 3 years.
Sow seeds indoors 6 to 8 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 12 to 20 inches apart.
wide spacings if you want to harvest large central heads. Closer
spacings will produce smaller central heads. But if you harvest
secondary heads you will get a greater total yield from the closer
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.
Can be direct-seeded as soon
as you can work the soil. Will germinate at soil temps as low as 40 F.
Plant ½ to ¾ inch deep, about 3 inches apart. Thin to final spacings.
Direct seed in midsummer for fall crop, or start transplants in late May and transplant in late June or early July.
In Zone 7 and warmer, fall broccoli crops will often overwinter.
Use low nitrogen fertilizer at planting. Too much nitrogen fertilizer may cause hollow stems.
have shallow root systems. Avoid even shallow cultivation. Mulch to
protect roots, reduce weed competition and conserve moisture.
Use floating row covers to help protect from early insect infestations.
To help reduce disease, do not plant broccoli or other cole crops in the same location more than once every three or four years.
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.
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.
Slugs and snails