How to grow broccoli raab
Family Brassicaceae. Hardy to USDA hardiness zone 3a+ (U.S. Department of Agriculture). Full sun. Ready in 40-50 days.
Sun
Full sun
Spacing
6-8 in
Days to harvest
40-50 days
Hardiness
Zone 3a+
What growers actually recorded
Loading zone 7b results…
When to plant broccoli raab
- Direct sow: ~-4 weeks after last frost.
Companion plants for broccoli raab
Plant with: Onion, Dill, Beet.
Avoid near: Tomato, Strawberry.
Common pests & problems
Flea beetle, cabbage worm, aphid.
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
Harvest before the small yellow flowers fully open: once they're wide open the stems turn bitter.
When to plant broccoli raab 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 raab
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
- Harvest when the central flower buds are visible but still tight and green, before any yellow petals show.
- Cut the stalk 6-8 in from the top, including a few leaves; the plant regrows side shoots for a second cutting.
- Bolting to flower is the crop's normal habit, not a failure: broccoli raab is grown specifically for its flower stalks and buds, not a large head.
Storing & keeping
Refrigerate unwashed in a perforated bag at 32-40°F for 3-5 days; it is more perishable than standard broccoli. Blanch and freeze for longer storage.
What to expect
Per plant: 0.5-1 lb across the main cut and side shoots
Per sq ft: 0.5-1 lb per sq ft
Troubleshooting broccoli raab
Flowers open yellow before harvest
Likely cause: Left in the field too long once buds form
What to do: Check plants every 1-2 days once buds appear; the harvest window is narrow, often just a few days.
Bitter flavor
Likely cause: Heat stress or delayed harvest
What to do: Grow in cool spring or fall weather and harvest promptly; a quick blanch before cooking also tames bitterness.
Varieties worth growing
Sorrento
Standard Italian raab type, fast to bud and reliable for repeat cutting.
Spring Raab
Bred to be slower to bolt fully to flower, extending the tender-bud harvest window.
Growing broccoli raab in containers
8-10 in deep pot; grows quickly enough in containers to make a viable short-season crop.
Nutrition
Sulforaphane, glucosinolates, vitamin K, calcium. Brassicas are the vegetable powerhouse.
Common questions
Is broccoli raab actually broccoli?
No, despite the name it is more closely related to turnip (Brassica rapa) than to true broccoli, and it is intentionally harvested while bolting to flower.
Why does mine taste so bitter compared to store-bought?
Bitterness increases with plant age and heat stress; harvest young buds promptly and in cool weather for the milder flavor typical of well-grown raab.
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.