Broccoli & Cauliflower in the Desert

Broccoli and cauliflower are often described as "tricky" in Phoenix, but that's mostly a timing problem. Get the planting date right and they're actually quite straightforward — and harvesting a perfect head of broccoli in December, when your friends in colder climates are buying it from a grocery store, feels excellent.

The key is understanding that these crops need to mature in cool weather, not just grow. They form heads (called "heads" for broccoli, "curds" for cauliflower) only when daytime temperatures are consistently in the 65–80°F range. Our October through December window is ideal.

When to Plant

Set out transplants in September through mid-October. September plantings harvest in November-December. October plantings harvest in January. Both windows work; September gives you the longest and most productive plants.

Starting from seed: start 4–6 weeks before your transplant date (late July or August) indoors under lights. This is tricky in Phoenix summer heat — seed-starting is easiest in a cool indoor space with grow lights. Many gardeners just buy transplants from nurseries in September, which is easy and reliable.

Best Varieties for Phoenix

Broccoli

• Calabrese — Classic Italian broccoli, large central head followed by abundant side shoots. Excellent for Phoenix.
• Green Magic — Compact, early-maturing (60 days), very reliable. Great for smaller gardens.
• Di Cicco — Heritage Italian variety, smaller central head but prolific side shoots over many weeks. Very productive.
• Romanesco — Stunning spiral chartreuse heads, nutty flavor. Technically closer to cauliflower. Beautiful in the garden and the kitchen.

Cauliflower

• Snow Crown — Early (50 days), reliable, and one of the most heat-tolerant cauliflowers available. Good for Phoenix.
• Purple of Sicily — Purple-headed heirloom, slightly more heat-tolerant than white varieties. Turns green when cooked.
• Cheddar — Orange-pigmented, visually striking, slightly sweeter flavor than white cauliflower.

Spacing & Soil

These are large plants — give them 18–24 inches of space in each direction. They're heavy feeders, so amend soil generously with compost and add a balanced fertilizer before planting. Side-dress with additional fertilizer 4 weeks after transplanting.

Blanching Cauliflower

White cauliflower heads turn yellow and develop off-flavors if exposed to sunlight as they develop. When the curd first becomes visible (about the size of a golf ball), tie the outer leaves over it with a rubber band or twine to block sunlight. Check every few days — white cauliflower can go from golf ball to harvest-ready in less than a week in December warmth.

Colored varieties (purple, orange) don't need blanching.

Harvesting

Harvest broccoli when the central head is tight and dark green — before any yellow flower petals begin to show. Cut the central head, then leave the plant in the ground. It will produce smaller side shoots over the next several weeks, extending your harvest significantly.

Harvest cauliflower when the curd is firm and compact — don't let it get loose or "ricey." Once it starts to separate, quality declines quickly. When in doubt, harvest a day early.