Broccoli
Brassica oleracea
About it
- Kind
- Vegetables · Annual
- Family
- Brassicaceae
- Hardiness zones
- Zones 2–11
- Frost
- Hardy — takes a hard frost
- Sun
- Full sun
- Spacing
- 18 in apart, rows 24 in
- Soil depth in a pot
- At least 12 in
- Soil pH
- 6–7.5
- Water
- About every 7 days
When to plant
- Start indoors
- 6 weeks before planting out
- Plant out
- Plant out 4 weeks before the last frost
- Window
- Open for about 3 weeks
- Soil temperature
- Germinates from 40°F
- Ready
- About 80 days from planting out
Based on your last frost date. Outside the US, check local advice.
Varieties people grow
- Calabrese Green Sprouting— Italian heirloom; central head then side shoots
- De Cicco— heirloom grown mainly for its side shoots
- Green Magic— takes heat better than most; even heads
- Waltham 29— open-pollinated autumn broccoli; cold tolerant
Planting partners
What has been claimed about growing Broccoli near other plants, grouped by how well it has been tested. Most companion planting advice has never been tested; the notes say which is which.
Tested in field trials
- With Nasturtium Nasturtiums planted with broccoli reduced cabbage looper and imported cabbageworm damage in an Iowa study. UMN Extension ↗
- With Onion Onions planted with broccoli reduced cabbage looper and imported cabbageworm damage in an Iowa study. UMN Extension ↗
- With Thyme Thyme planted with broccoli reduced cabbage looper and imported cabbageworm damage in an Iowa study. UMN Extension ↗
- With Chinese Cabbage Napa cabbage grown as a trap crop beside other brassicas draws flea beetles away from them; in trials only a mix of three trap-crop species improved the protected broccoli's yield. UMN Extension ↗Europe PMC ↗
- With Mustard Greens Mustard grown as a trap crop beside other brassicas draws flea beetles away from them; in trials only a mix of three trap-crop species improved the protected broccoli's yield. UMN Extension ↗Europe PMC ↗
Mixed evidence
- With Green Onion Green onions are often planted to keep flea beetles off brassicas, but little research supports it and some contradicts it. UMN Extension ↗
- With Marigold Marigolds are often planted to keep flea beetles off brassicas, but little research supports it and some contradicts it. UMN Extension ↗
Safety for pets and children
- Cats No information in our sources
- Dogs No information in our sources
- Horses Listed as a problem for horses (NC State Extension)
- Children No information in our sources
If a pet or child eats part of this plant, call your vet or poison control.
Read from NC State Extension ↗.
"No information" means our sources do not say, not that the plant is harmless. A non-toxic listing is not a reason to let anyone eat a plant.
Pests and diseases
Cabbage caterpillars Insect
What you'll see. Green caterpillars of the imported cabbageworm, cabbage looper and diamondback moth chew holes in the leaves, and seedlings and new transplants are hurt most.
What helps. Cover young plants with floating row cover, which keeps the moths from laying eggs on them. Check the undersides of leaves and handpick caterpillars and eggs.
Source: NC State Extension ↗,UMN Extension ↗
Clubroot Disease
Plasmodiophora brassicae
What you'll see. Plants are stunted and wilt easily, leaves may yellow, and the roots swell into thick, distorted clubs.
What helps. Grow from seed or inspect transplant roots before planting, use only compost that has heated fully, and clean soil off tools. Where clubroot has appeared, grow no cabbage-family crops there for five to seven years and keep weeds out meanwhile.
Source: UMN Extension ↗,UMN Extension (2) ↗
Flea beetles Insect
What you'll see. Tiny jumping beetles chew many small round holes in the leaves, and seedlings are hurt most.
What helps. Cover young plants with row cover, and clear weeds and old crop debris where the beetles spend the winter. Sowing a little later in the season lets plants grow quickly past the worst of the feeding.
Source: UMN Extension ↗,UMN Extension (2) ↗
Check the label and your local extension service before using any product.
Where this comes from
- family npgsweb.ars-grin.gov ↗ GRIN page: Brassica oleracea L. var. italica Plenck (the catalogue row names only Brassica oleracea)
- frost hardiness cmg.extension.colostate.edu ↗ CSU #720 (Colorado) hardy class lists broccoli
- maturity counted from cmg.extension.colostate.edu ↗ Row's 80 days is NC State (North Carolina) Table 16-4's T=70-80; CSU #720 (Colorado) counts broccoli from transplant (65T)
- maturity counted from NC State Extension ↗ Row's 80 days is NC State (North Carolina) Table 16-4's T=70-80; CSU #720 (Colorado) counts broccoli from transplant (65T)
- min soil temp f cmg.extension.colostate.edu ↗ CSU #720 (Colorado) Table 1: broccoli germination minimum 40°F
- Most facts UMN Extension ↗ Backfilled by 0041. Pre-0041 rows recorded one source for the whole row; per-field attribution was never captured and is not invented here.
- sow window weeks extension.unh.edu ↗ UNH (New Hampshire) 2-4 weeks before last frost: weeks -4 to -2
- toxicity NC State Extension ↗ toxic for horse from the page's "Problem for" listing. Page matched to this row by its title (Brassica oleracea Cauliflower & Broccoli Group, whose common names include sprouting broccoli and calabrese); not cited by the row before this batch.
- transplant weeks rel last frost extension.unh.edu ↗ UNH (New Hampshire) table: broccoli set out 2-4 weeks before last frost; the earlier week. CSU #720 (Colorado) hardy class gives the same 2-4
- water frequency days UMN Extension ↗ UMN "Growing broccoli": "If the planting does not receive one inch of rain each week, soak the soil thoroughly at least once a week." and "If your soil is sandy, water more often than once a week."