USA plant library · vegetable

Broccoli

Brassica oleracea (Italica Group) · Brassicaceae

Popular cool-season brassica

Photo: Kolforn (Kolforn), CC BY-SA 4.0, via Wikimedia Commons

Sun: Full sun (6+ hours)
Soil: Fertile, well-drained, moist soil
Soil pH: About 5.8-7.0
Water: About 1 in per week, watering deeply to 6 in
Hardiness: Cool-season annual. Tolerates light frost and is not seriously damaged down to about 28°F
Height and spread: Typically 2-3 ft tall; range 1-4 ft tall x 1-2 ft wide

Guv's tipCut broccoli's main head before the buds open, and side shoots will follow. Floating row covers help keep imported cabbageworm off.

Through the year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Sow or plant

Harvest

Months are a rough guide. Time it by your own frost dates: outdoors before last frost (cool season).

When to plant

Spring: transplant 2-3 weeks before the last frost (Mar-Apr in the South, Apr-May in the North; in Minnesota start seed indoors early-mid Apr). Fall: plant in Jul in the North to Aug-Sep in the South (South Carolina transplants Aug 15-Sep 30)

Harvest or flowering

Heads form 50-90 days after transplanting: about May-Jul from spring plantings and Sep-Nov from fall plantings. Harvest before the buds open

Pruning

Cut the main head; side shoots follow

Making more plants

Seed or transplants

Watch out for

Pest

Imported cabbageworm

Look for: Green caterpillars, holes in leaves, frass in heads

What to do: Floating row covers; Bacillus thuringiensis (Bt) on young caterpillars

Pest

Cabbage aphid

Look for: Gray-green waxy colonies on young leaves and heads, curled leaves

What to do: Hose off; insecticidal soap with good coverage; conserve lady beetles and parasitoids

Disease

Black rot

Xanthomonas campestris pv. campestris

Look for: Yellow V-shaped lesions from leaf margins, blackened veins

What to do: Clean seed/transplants, 2+ year rotation away from brassicas, remove residue

Disease

Downy mildew

Hyaloperonospora spp. (H. parasitica / H. brassicae complex)

Look for: Angular yellow-brown leaf spots with grayish-white fluffy growth underneath; dark streaks in heads

What to do: Spacing and air flow, avoid overhead watering, rotation, resistant cultivars; labeled protectant fungicide if needed

Always read and follow the label on any treatment, and check it is approved for use where you live.

Safety and spread

Pets and people: Not listed on the ASPCA toxic plant list. Safe for dogs in small amounts, but isothiocyanates in the florets can cause stomach irritation in larger amounts

Weed risk: Not on the federal noxious weed list. The USDA PLANTS database shows no federal or state noxious or invasive status

Checked against two or more reputable gardening sources. How we check our facts

Keep it by the back door

The Plant Doctor and the Guv's book

Printable pest and disease charts with real photographs, and all 50 USA plants in one book.

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