How to grow broccoli
Family Brassicaceae. Hardy to USDA hardiness zone 3a+ (U.S. Department of Agriculture). Full sun. Ready in 60-90 days.
Sun
Full sun
Spacing
18-24 in
Days to harvest
60-90 days
Hardiness
Zone 3a+
What growers actually recorded
Loading zone 7b results…
When to plant broccoli
- Start indoors: ~6 weeks before last frost.
- Transplant out: ~-3 weeks after last frost.
- Direct sow: ~-3 weeks after last frost.
Companion plants for broccoli
Plant with: Onion, Beet, Herbs.
Avoid near: Tomato, Strawberry.
Common pests & problems
Cabbage worm, aphid. Row cover.
Feeding & fertilizer
N-P-K ratio: High N (10-5-5): heavy feeders
Organic options: Aged manure or compost worked in deep · Blood meal or feather meal side-dress at 3 wks · Fish emulsion every 2 wks
When to feed: Feed heavily every 2-3 weeks. Brassicas want steady nitrogen for tight heads.
Watch for: Pale/yellow leaves = needs N. Loose heads = feed harder next round.
N = nitrogen (leaves), P = phosphorus (roots and flowers), K = potassium (fruit and disease resistance). How to read a fertilizer label →
Grower's tip
After cutting the main head, side shoots keep coming for weeks: don't pull the plant.
When to plant broccoli in your zone
Free month-by-month sowing and transplanting lists, built from frost dates for your USDA (United States Department of Agriculture) hardiness zone.
Soil & water for broccoli
Soil & pH
6.5-7.5: near neutral (raises club-root resistance)
Fertile loam with strong drainage. Firm soil beats fluffy for heading brassicas.
Compost 2 in + 1 cup of alfalfa or feather meal per 10 sq ft. Lime if pH is under 6.5. It also blocks club-root.
Watering
1-1.5 in / week, consistent
Ground-level drip. Uneven water during heading = split heads or bolting.
Lift an edge of the row and check soil at 3 inches. If it clings in a damp ball, hold off. If it crumbles, water until the top 6 inches are evenly moist.
Knowing when to harvest
- Main head: tight buds, no yellow showing. Once yellow flowers appear, flavor drops fast.
- Cut 5-6 in of stem. New side-shoots produce for 4-6 more weeks.
- Harvest at dawn when heads are cool and firm.
Storing & keeping
Crisper 5-7 days; blanch 3 min and freeze for 8-12 months.
What to expect
Per plant: 1 main head (6-8 in) + 1 lb side shoots
Troubleshooting broccoli
Loose, open heads
Likely cause: Heat above 80°F during heading, or under-fed
What to do: Spring or fall crops only; steady N through heading; shade cloth in warm springs.
Hollow stem
Likely cause: Boron deficiency
What to do: 1 tsp borax dissolved in 1 gallon water, foliar spray once at heading.
Varieties worth growing
Belstar
Reliable in heat, uniform heads.
Green Magic
Fast (55 days), good for succession sowings.
Piracicaba
Sprouting broccoli, no main head, endless side shoots.
Growing broccoli in containers
5-gallon per plant; feed weekly with fish emulsion.
Nutrition
Sulforaphane, glucosinolates, vitamin K, calcium. Brassicas are the vegetable powerhouse.
Common questions
Why did my broccoli bolt without heading?
Transplant shock or heat spike. Brassicas exposed to under-50°F nights after being warm will 'button' (form tiny heads and bolt). Wait for stable warmth to transplant.
Where these numbers come from
- USDA Plant Hardiness Zone Map (2023 revision). Zone assignment and the 30-year normals behind every cold-hardiness figure.
- NOAA NCEI 1991-2020 Climate Normals. Frost dates, growing-season length, and the probability bands on both.
- Cornell, UMN, and UC Davis Cooperative Extension crop guides. Spacing, days to maturity, soil pH targets, and per-plant yield ranges.
- USDA FSIS / FDA Produce Safety guidance. Wash, cure, and cold-storage handling numbers.
Ranges are regional guidance, not a promise for your yard. Your own logged results always override the published range.