Broccoli is a cool-season star: a big central head followed by months of tasty side shoots if you keep picking. It is one of the most nutritious vegetables you can grow, and freshly cut broccoli — sweet, tender and deep green — is a different vegetable from the tired heads in the shops.
Broccoli likes cool weather, rich soil and steady water, and it sulks in summer heat.
Broccoli at a glance
| Growing factor | What broccoli need |
|---|---|
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Days to germination | 7–14 |
| Days to maturity | 60–85 |
| Spacing | 18–24 inches |
| Water needs | moderate |
| Cold tolerance | frost-tolerant |
| Family | Brassicaceae |
Starting seeds
This crop can be started indoors or sown direct, and either route works well. Indoors, sow in trays, cells or small pots and expect germination in 7–14 days; direct-sown seed goes into a prepared bed once conditions are right. Starting indoors buys a few weeks of season and steadier germination, while direct sowing is simpler and avoids transplant shock.
Shorter-season gardens in the cooler zones gain the most from starting indoors, while warmer zones can usually direct-sow with confidence. Our seed-starting calculator works out indoor sowing dates from your frost dates. Zones 11–13 are frost-free, so sowing windows there are about heat and rain instead — check your local extension service.
Broccoli can be started indoors or sown direct, and starting indoors is the usual approach for a spring or autumn crop. Sow in trays or cells, pot seedlings on once they have a few true leaves, and grow them into sturdy young plants before planting out. Direct sowing works too, but the young plants are an easy target for slugs, so indoor-grown plants have a better start.
Transplanting and planting out
Plant broccoli out when the young plants are sturdy, at their full spacing — they grow into big plants with wide leaves. Firm them in well, since loose plants rock in the wind and never settle, and water them in thoroughly. Netting or fine mesh over the bed from day one keeps cabbage butterflies from laying eggs, and a mulch layer helps hold the moisture that broccoli loves.
Space plants 18–24 inches apart — crowding is one of the commonest causes of small harvests. Our plant-spacing calculator works out how many plants fit your bed.
Soil and feeding
Broccoli grow best in rich, well-drained soil with plenty of organic matter. Dig in compost before planting: it improves heavy soil, helps light soil hold moisture, and feeds the soil life that feeds your plants. Aim for a soil pH of 6.0–7.0 — a simple soil test will tell you where you stand, and garden lime or sulfur can nudge pH up or down over a season, so test before you amend rather than guessing.
Feed lightly and steadily rather than in one heavy dose: too much fast nitrogen late in the season pushes leafy growth at the expense of the part you eat. Our fertiliser calculator works out amounts for your bed size, and the soil-volume calculator tells you how much mix a new bed needs.
Watering
Water needs are moderate: keep the soil evenly moist, watering deeply when the top inch or two dries out. Deep, infrequent watering builds deeper roots than a daily sprinkle.
Water at the base of the plant, in the morning, so the leaves dry quickly and the water reaches the roots. Our watering calculator gives a starting point for your bed size, and the watering schedule generator can build a routine around it. A mulch layer cuts evaporation and keeps moisture even.
Sunlight and temperature
Broccoli need full sun — a spot that gets sun for most of the day. Our sunlight calculator can check your spot.
This crop is rated frost-tolerant for cold tolerance, so it stands up to light frosts and is at its best in the cool seasons. In Zones 11–13, which are frost-free, heat rather than cold is the limit — grow it in the cooler months, with afternoon shade in the hottest weather. Our hardiness-zone finder will confirm your zone, and the frost-date calculator gives you the frost dates to plan around.
Pests and diseases
The pests and diseases most often reported on broccoli are cabbage worms, aphids, flea beetles, slugs. Healthy, well-watered plants resist attack better than stressed ones, and rotating beds so the Brassicaceae family does not repeat in the same spot helps keep soil-borne problems down.
- Cabbage Worms — small green caterpillars that chew holes in brassica leaves; fine mesh from planting time keeps the butterflies off.
- Aphids — small sap-sucking insects on new growth; wash off with a strong jet of water and encourage ladybirds.
- Flea Beetles — tiny jumping beetles that chew shot-holes in leaves, worst on seedlings; row cover keeps them off young plants.
- Slugs — chew ragged holes in leaves at night; water in the morning so the surface dries by evening.
Inspect plants weekly, especially leaf undersides, and act early. Our pest-identifier helper can help identify what you are seeing.
Companion plants
Good companion plants for broccoli include:
- Marigolds — their roots discourage some soil pests
- Basil — attracts pollinators
- Onions — their scent is said to confuse pests
- Lettuce — shallow-rooted, fills gaps without competing
Our companion-planting finder can suggest more pairings for your bed plan.
Harvesting
Cut the central head while the buds are still tight and green, before any yellow flowers open — once it flowers, the head is past its best. Cut the stem at an angle a few centimetres below the head, and the plant will send out side shoots from the leaf joints for weeks afterwards. Pick those small and often, and a single plant can keep you in broccoli for a long time.
Expect the crop to be ready about 60–85 days after sowing, though weather and variety shift that window by a week or two either way. Our harvest-date calculator works out your expected harvest date from your sowing date, and the vegetable-yield estimator can estimate how much a bed should produce.
Common problems and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Small heads, or buttoning | stress when young — heat, drought or root disturbance | Broccoli heads stay small if the young plant is checked by heat, drought or rough handling. |
| Plants bolting to flower | hot weather | Broccoli bolts in heat, so time sowings for spring and autumn. |
| Caterpillars eating the leaves | cabbage white butterflies laying eggs | Fine mesh netting over the bed from planting time is the best defence. |
Small heads, or buttoning
Broccoli heads stay small if the young plant is checked by heat, drought or rough handling.
Plants bolting to flower
Broccoli bolts in heat, so time sowings for spring and autumn.
Caterpillars eating the leaves
Fine mesh netting over the bed from planting time is the best defence.
Frequently asked questions
When should I plant broccoli?
Sow once the soil is workable in spring — this crop is rated frost-tolerant for cold tolerance, so it can go in early. For zone-specific timing, see zone 4 or zone 7, and check your local extension service for the dates that fit your area.
How long do broccoli take to grow?
Broccoli take 60–85 days from sowing to maturity, and seed germinates in 7–14 days. Weather and variety shift the harvest window by a week or two, so judge readiness by look and feel rather than the calendar alone.
How far apart should I plant broccoli?
Space plants 18–24 inches apart — that is the room a mature plant needs, and crowding means poor airflow and small harvests. Our plant-spacing calculator works out how many fit your bed.
How do I get side shoots from broccoli?
Cut the central head while the buds are tight, leaving a good length of stem. Within a week or two, small shoots will sprout from the leaf joints below the cut — pick these when they are a few centimetres long and the plant will keep producing more.