Cauliflower · Perth, WA
A local how-to for Perth’s mediterranean/temperate climate, the planting window, the spacing, the pest pressure, and the family-of-four quantities. Built for raised beds.
The local entry
Plant cauliflower in Perth january-may, july-september.
Climate: Mediterranean/Temperate · Spacing: 60 cm · Days to harvest: 80-120 days · Sun: full
Planting window
January-May, July-September
Spacing
60 cm
70 cm rows
Sun
Full sun
Water
High
Growing cauliflower in Perth sits inside a specific window, january-may, july-september, and the success of the crop hinges on respecting it. Perth's mediterranean/temperate climate runs winter lows of about 9°C and summer highs around 35°C, with frost risk: Frost-free (coastal), rare light frosts in hills July-August. Those numbers are the ones every Perth gardener already knows by feel; they're the reason why the same crop behaves differently in a Sydney raised bed compared to a Hobart one.
Start with the bed itself. A raised bed of at least 30 cm depth gives cauliflower room for roots to extend, and in Perth, that depth also buffers the soil temperature against the swings that catch out shallow planters. Work compost through the top 20-30 cm until the bed mix is loose and friable. Target a soil pH of 6.0-7.5, which is the band cauliflower prefers. If your Perth water is alkaline (which it often is on the mainland), add a handful of sulphur or composted leaves to nudge the pH down. See our raised bed calculator if you’re sizing the bed from scratch.
Perth's dry summers require drip irrigation or soaker hoses rather than overhead watering, conserve water and reduce fungal disease risk simultaneously.
Space plants 60 cm apart, with 70 cm between rows. A standard 1.2 m × 2.4 m raised bed in Perth holds up to 6 cauliflower plants at maximum density, though in practice you'll plant 60-70 percent of that to leave room for Dill and Sage. Full sun (6+ hours daily). High, consistent moisture throughout; water stress causes premature heading. If you want the full plant-by-plant spacing reference, the plant spacing chart is the printable version.
Cauliflower is the most demanding brassica to grow and the most sensitive to growing conditions. Its ideal growing temperature is 10-18°C, too cold and the plant 'bolts' to button heads; too warm and it produces the same result. In most Australian climates, this means autumn to late winter is the cauliflower season. Start seeds indoors 4-6 weeks before transplanting. Seedlings should be well established (6-8cm tall, stocky) before transplanting into the final bed. Handle roots carefully and water in with seaweed solution to reduce transplant shock.
In Perth's mediterranean/temperate conditions, cauliflower faces the usual seasonal pests but has a long enough productive window to ride them out. Cabbage white butterfly caterpillars devastate cauliflower, use fine insect exclusion netting or Bt spray from transplanting. Buttoning (tiny premature heads) is caused by temperature stress, root damage, or drought, plant at the right time and maintain consistent moisture. Perth's dry summers require drip irrigation or soaker hoses rather than overhead watering, conserve water and reduce fungal disease risk simultaneously.
Good companions for cauliflower in Perth’s climate include Dill, Sage, Thyme, Celery. These pairings reduce pest pressure and improve pollination. Keep cauliflower away from Tomato, Strawberry, Fennel because they fight for the same nutrients or attract shared pests. The full matrix lives in our companion planting guide.
When it comes to the harvest itself, Harvest cauliflower when the curd is compact, tight, and white (for white varieties), at 15-20cm diameter. Once the surface begins to separate and take on a grainy texture, it is overripe. Cut the whole head with a sharp knife, leaving some of the stem and surrounding leaves attached. Side shoots sometimes develop after harvest, producing smaller but edible secondary curds. Expect around 1 head per plant (500g-1.5kg); possible side shoots. For a Perth household of four, Plant 6-8 plants staggered over 4-6 weeks for sequential harvest for a family of 4
Perth gardeners tend to do their best work when they stop treating the year as one long growing season and start treating it as a series of windows. The window for cauliflower in your climate is january-may, july-september, set a reminder for the weekend before it opens, get the seedlings in, and the rest is just looking after them.
Perth record
The numbers above sit behind every recommendation on this page. They’re the same climate signal Plant Planner reads from your postcode, see frost dates by city for the longer view.
Plant cauliflower in Perth january-may, july-september. Use a raised bed at least 30 cm deep with compost-rich mix, space plants 60 cm apart in rows 70 cm apart, give it full sun (6+ hours daily), and water consistently. Expect 80-120 days from planting to first harvest.
In Perth (mediterranean/temperate climate, frost risk: Frost-free (coastal), rare light frosts in hills July-August), the productive window for cauliflower is january-may, july-september. Within that window, planting in the first two weeks gives the longest harvest tail.
Plant 6-8 plants staggered over 4-6 weeks for sequential harvest for a family of 4 Expected yield per plant: 1 head per plant (500g-1.5kg); possible side shoots. Plant Planner runs this calculation against your exact household size when you sign up.
Good companions in Perth include Dill, Sage, Thyme, Celery, Beetroot. These pairings reduce pest pressure and improve pollination in Perth's mediterranean/temperate climate. Keep cauliflower away from Tomato, Strawberry, Fennel, they compete for nutrients or attract shared pests.
Full sun (6+ hours daily). In Perth's mediterranean/temperate climate, morning sun and some protection from the harshest afternoon sun in midsummer works best.
Cabbage white butterfly caterpillars devastate cauliflower, use fine insect exclusion netting or Bt spray from transplanting. Buttoning (tiny premature heads) is caused by temperature stress, root damage, or drought, plant at the right time and maintain consistent moisture. Hollow stem indicates boron deficiency, apply borax solution preventively. Club root is a serious soilborne disease, lime the bed to maintain pH above 7.0.
Tell us your postcode, family size, and the size of your bed. The planner runs the maths, lays out the bed, and emails you the planting reminders when the weekend before each task arrives.
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