How to grow Broccoli in Australia
Broccoli is one of the most rewarding cool-season vegetables: one big central head, then weeks of tender side shoots after it is cut. It wants firm, rich, limed soil, steady water and cool weather while the heads form. The main job in most gardens is keeping the caterpillars off.
📖 Our full guide: How to Grow Broccoli in Australia
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| South East Queensland | February to May | |
| Northern Rivers NSW | February to June | One more sowing month than SEQ. Colder winters suit brassicas. |
| Sydney & Coastal NSW | February to July | Cool winters extend harvest; June plantings successful for winter harvest. |
| Melbourne & Victoria | February to June | Seed indoors Feb to Apr, transplant Apr to Jun. Longer season than SEQ; tolerates cold winters. |
| Adelaide & SA | February to July | Sow Feb to Jul. Feb to Mar sowings beat winter and give the biggest heads; later sowings harvest in spring. Summer sowings fail in the heat. |
| Perth & WA | February to September | Start trays from mid Feb in bright shade out of afternoon sun, transplant Mar to May. Direct sow Mar to Sep; fails in summer heat. |
| Tasmania | September to January | Sow Sep for a summer crop and Nov to Jan for the main autumn-winter harvest. Tasmania grows superb broccoli. |
| Canberra & ACT | November to January | Sow from November to January and transplant from January to March for autumn and winter heads. This follows the planting timing of the Canberra Organic Growers Society (COGS). |
| North Queensland | May to July | Dry season only. Broccoli very marginal in tropics; sow May to Jul with shade cloth mandatory. |
| Darwin & Top End | May to July | Dry season only. Broccoli very marginal in tropics; sow May to Jul with shade cloth mandatory. |
Where to plant
Grow broccoli in full sun in firm, rich, well-drained soil with plenty of compost. Brassicas prefer soil that is close to neutral: if your soil is acid, add dolomite or garden lime a few weeks before planting, which also helps to prevent clubroot. Do not plant where cabbage family crops grew in the last few years.
Broccoli forms its best heads in cool weather. Heads that mature in hot weather loosen and run to flower quickly.
- South East Queensland and the Northern Rivers: sow from February to May or June for winter heads.
- Sydney and Adelaide: sow from February to July. Early sowings in February and March give the biggest heads before winter.
- Melbourne: raise seedlings from February to April and plant out from April to June.
- Perth: start seedlings in trays from mid February in bright shade, and plant out from March to May.
- Canberra and Hobart: sow from late spring to early summer (November to January) and plant out for autumn and winter heads. In Hobart a September sowing gives a summer crop.
- North Queensland and Darwin: very marginal; sow from May to July in the dry season, with shade cloth.
Choosing a variety
- Heading types form one large central head, then smaller side shoots.
- Sprouting types produce many smaller spears over a long season rather than one big head.
- Broccolini is a separate, quicker crop of long, tender stems.
How to plant
- Sow seed about 1 cm deep in punnets, or direct, and keep moist; seedlings appear in about a week.
- Plant out seedlings at four to six weeks, when they have a few true leaves, about 40 to 50 cm apart.
- Plant firmly. Broccoli does best in firm soil, so tread the soil down gently around each plant.
- Water in with a seaweed solution and mulch.
- Cover with fine insect netting straight away to keep cabbage white butterflies and moths off.
Watering and feeding
Water deeply and regularly, never letting the soil dry out. Stress from drought or heat makes heads small and quick to flower.
Broccoli is a hungry crop. Dig in compost and a little blood and bone before planting, then side dress or liquid feed with a nitrogen-rich fertiliser every two or three weeks while the plants grow.
Pruning and care through the year
- Keep netting on until harvest; caterpillars can strip young plants in days.
- Check the undersides of leaves for eggs and caterpillars, and for grey aphid colonies in spring.
- Earth up a little soil around the stem of tall plants if they rock in the wind.
Harvesting
Cut the main head while it is large but the buds are still tight and green, before any yellow flowers show. Cut the stem on a slant about 10 to 15 cm below the head.
Most varieties then grow side shoots from the leaf joints. Pick these as they form, every few days, and the plant can keep producing for weeks, sometimes up to three months, until it finally runs to flower. Broccoli keeps a few days in the fridge.
Growing in pots
Broccoli can grow in a large pot, at least 40 cm wide and deep, one plant per pot. Use a rich potting mix, water often and feed regularly. Heads are usually smaller than in the garden.
Companion planting
Aromatic herbs and flowers that bring in helpful insects suit the cabbage family. Keep crops with different needs, and other brassicas, out of the same bed.
Good companions
- Dill Its flowers feed tiny parasitic wasps and hoverflies that attack caterpillars and aphids.
- Chamomile A low flowering herb that brings in hoverflies.
- Nasturtium A sacrificial plant that draws aphids and cabbage white butterflies away from the crop.
- Celery Shares the same cool season and rich, moist soil.
- Onion Narrow plants that fit between broccoli without competing for space.
- Beetroot A root crop that uses different space in the bed.
- Rosemary An aromatic herb traditionally grown near brassicas; plant it at the edge of the bed, as it likes drier soil.
- Sage Another aromatic herb traditionally grown near brassicas, best at the bed edge.
Keep apart
Avoid planting these close to broccoli.
- Tomato A warm-season crop with different timing and feeding needs; give each its own bed.
- Strawberry Traditionally kept away from the cabbage family.
- Climbing beans Tall summer climbers that shade low winter crops and need different timing.
Pests and diseases
Caterpillars of the cabbage white butterfly, cabbage moth and diamondback moth are the main pests. Netting from planting is the most reliable control.
Pests to watch for
- Cabbage moth Holes chewed in leaves and green caterpillars or droppings in the heads. Includes cabbage white butterfly and diamondback moth. Net plants and pick off caterpillars.
- Aphids Dense colonies of grey, waxy cabbage aphids on leaves and in the heads, especially in spring.
Diseases to watch for
- Clubroot Plants wilt on warm days and the roots are swollen and distorted. It stays in the soil for years: lime acid soil and rotate brassica beds.
- Downy mildew Yellow patches on upper leaf surfaces with grey-white fuzz underneath in cool, damp weather.
Common questions
Why is my broccoli flowering before it forms a proper head?
Heat or stress makes broccoli bolt. Sow so the heads form in cool weather, water deeply and regularly, and feed steadily. Heads that mature in warm spring weather loosen and flower quickly.
Does broccoli grow back after cutting?
Most varieties grow side shoots after you cut the main head. Pick them every few days and the plant can keep producing for weeks, sometimes up to three months.
When is broccoli ready to pick?
When the head is large and the buds are still tight and green. Cut it before any yellow flowers appear.
How do I stop caterpillars on my broccoli?
Cover plants with fine insect netting from the day you plant them, so butterflies and moths cannot lay eggs. Check leaves for caterpillars and eggs, and pick them off.
When should I plant broccoli?
In most areas, sow from late summer to autumn so heads form in the cool of winter. In Canberra and Hobart sow from late spring to early summer for autumn heads. Pick your region at the top of the page for the months.
Why is my broccoli head so small?
Usually stress: dry soil, heat, not enough food, or seedlings that sat too long in the punnet before planting. Plant out young, keep the soil moist and feed every few weeks.
Do I need to add lime for broccoli?
If your soil is acid, yes. Brassicas prefer soil close to neutral, and liming acid soil a few weeks before planting also helps prevent clubroot.
Sources we checked: Gardening Australia: Bountiful Brassicas; ABC Organic Gardener: Bountiful broccoli; ABC Organic Gardener: Grow your own organic broccoli; RHS: How to grow calabrese (broccoli).