Broccoli planting months by climate zone
The chart comes from the same data as the planting calendar. Tap a zone for its full calendar and the towns it covers.
| Zone | J | F | M | A | M | J | J | A | S | O | N | D | Sow or plant |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tropical | yes | yes | yes | yes | Apr–Jul | ||||||||
| Subtropical | yes | yes | yes | yes | Apr–Jul | ||||||||
| Arid and semi-arid | yes | yes | yes | yes | yes | yes | Feb–Jul | ||||||
| Temperate | yes | yes | yes | yes | yes | yes | Nov–Apr | ||||||
| Cool | yes | yes | yes | yes | yes | yes | Oct–Mar | ||||||
| NZ warm north | yes | yes | yes | yes | yes | yes | yes | yes | yes | Aug–Apr | |||
| NZ temperate | yes | yes | yes | yes | yes | yes | yes | yes | Sep–Apr | ||||
| NZ cool south | yes | yes | yes | yes | yes | yes | yes | yes | Sep–Apr |
sow or plantnot recommendedthis month
The windows run in opposite directions in the north and south. In the tropics and subtropics, broccoli is a dry-season crop planted in autumn and winter, because the wet-season heat stops it heading. Temperate and cool gardens plant from late spring to autumn. The later plantings head as the weather cools, which is the most reliable crop. In New Zealand the window opens in late winter or early spring.
Why heat and cold ruin the head
Iowa State University's extension service puts broccoli's best growing temperatures at 16–21 °C. Hot weather, with days of 30 °C or more and nights of 25 °C or more, can stop the plants forming heads at all. Cold causes a different fault, called buttoning, where a plant makes one small, early head and runs to flower. Iowa State lists three triggers for buttoning:
- long spells below about 10 °C
- dry soil
- poor soil
The University of Maryland adds that temperatures below about 7 °C can stop heading or make plants bolt. Iowa State also warns about the seedlings themselves: big, root-bound transplants button more readily than young ones. So buy or raise small, healthy seedlings and plant them out promptly. Maryland uses transplants 5–7 weeks old.
Raising broccoli from seed
Broccoli isn't in Oregon State University's classic germination table, but its close relatives cabbage and cauliflower are. They germinate in soil anywhere from about 4 °C to 38 °C. Warmer soil is faster, up to a point:
| Soil temperature | Cabbage: days to emerge | Cauliflower: days to emerge |
|---|---|---|
| 10 °C | 15 | 19 |
| 15 °C | 9 | 10 |
| 20 °C | 6 | 6 |
| 25 °C | 4 | 5 |
| 30 °C | 3 | 4 |
This is why summer-sown trays in temperate gardens come up in days. Sow in trays or punnets about 5–7 weeks before you want to plant out. Keep them growing steadily, and plant them out before they get leggy or root-bound.
Planting, feeding and watering
- Spacing: 40–50 cm apart, as in the calendar. The plant spacing calculator works out how many fit in a bed.
- Feeding: broccoli is a hungry crop. Maryland feeds it at planting, again three weeks later, and once more after cutting the main head to push the side shoots along. The fertiliser calculator turns a label rate into grams for your bed.
- Water: dry soil is one of the buttoning triggers, so keep moisture even. Mulch helps, and the watering calculator works out run times.
- Rotation: broccoli is a brassica. Grow it where brassicas haven't been for a few years, as in the crop rotation guide. Clubroot, a serious soil disease of brassicas, can last up to 20 years in the soil and favours warm, wet, acid ground.
Harvesting heads and side shoots
Cut the main head while the flower buds are still tight, before any yellow shows. Take it with about 15–20 cm of stem, as Maryland advises. Leave the plant in the ground. Smaller side heads, about 2.5–7.5 cm across, grow from the leaf joints over the following weeks.
Caterpillars
The green caterpillars of the cabbage white butterfly are a major pest of broccoli in warm months. The planting calendar's advice is to net young plants while the butterflies are about. Insect netting over hoops, tucked in at the edges, stops the butterflies laying eggs on the leaves.
Questions
When should I plant broccoli in Melbourne?
Melbourne is in the cool zone, where the calendar gives October to March. Plants set out in late summer and early autumn head in the cool of autumn and early winter, avoiding both summer heat and midwinter cold.
When should I plant broccoli in Brisbane or Sydney?
Brisbane is subtropical: plant from April to July, so the heads form in the dry, mild winter. Sydney is temperate, where the calendar runs from November to April. In both places, avoid heads forming in the heat of summer.
Why is my broccoli making tiny heads?
That is buttoning. Iowa State links it to long spells below about 10 °C, dry soil, poor soil and old, root-bound seedlings. Plant young seedlings, keep the soil moist and fed, and time the planting so heads form before the coldest weeks.
How long does broccoli take to grow?
About 60–90 days from planting seedlings to the first head, depending on the variety and the weather, with side shoots for weeks afterwards. Add 5–7 weeks if you start from seed.
Sources
- Iowa State University Extension, Growing broccoli in the home garden. Covers best growing temperatures, heat that stops heading, causes of buttoning, side heads and 60–75 days from transplanting.
- University of Maryland Extension, Growing broccoli in a home garden. Covers cold and heading, 5–7 week transplants, feeding, cutting the head with 15–20 cm of stem, and pests.
- Oregon State University Extension, Soil temperature conditions for vegetable seed germination, after J. F. Harrington, UC Davis. Covers cabbage and cauliflower.
- AUSVEG SoilWealth, Clubroot management in brassica vegetables (2024). Covers how long clubroot persists and the conditions it favours.
- Planting months, spacing and days to harvest: the GardenMaths planting calendar, from ABC Gardening Australia, the NT Government, Tui and others listed on each zone page.
Last reviewed 24 September 2026 · Report an error