Cauliflower At A Glance
- Cool season brassica for early spring or fall gardens.
- Cauliflower prefers full sun with moderately rich organic soils.
- Timing of seeding and transplanting are important for quality crops.
- Start seeds about six weeks prior to the last average frost date.
Follow the same planting instructions as you would for other vegetables.
- Use pre-moistened, seed starting mix free from fertilizer in trays, packs, or pots.
- Sow seeds 1/2 in. deep, place trays on consistent bottom heat of 70°-75°F, and cover tray with a plastic dome or wrap to help retain moisture but uncover and spritz with warm water as needed until seeds germinate in 7-14 days. (Seeds can be pre-soaked for eight hours prior to sowing to enhance germination)
- After emergence, uncover, remove from bottom heat, and place seedlings in bright direct sun or under grow lights with cooler room temperature.
- As seedlings develop true leaves, up-pot into slightly larger containers with clean, fresh, pre-moistened potting soil and water as needed.
- Transplant seedlings deep to allow buried stems to grow roots, which yields stronger plants.
- Plants seedlings out very early in spring as vegetative growth needs to happen before the flower head starts. If you expect a hard frost, cover the plants with a row cover, a sheet of plastic, or an old bed sheet to prevent frost damage.
- If seedling growth stalls out, fertilize with water-soluble 4-6-8 or 6-6-6 food at 1/2 strength, once per week.
- When plants are large enough, harden off for 7-10 days prior to planting out about two weeks prior to the last frost.
- Planting out too early or too late can lead to buttoning or bolting issues.
- Start new seeds by direct sowing in mid-summer for fall crops with seeds 1/2 in. deep, then thin to 15 in. apart with 2-3 ft. between rows.
- Cauliflower plants are prone to stress-induced maladies like buttoning or bolting. To avoid these common issues, transplant seedlings according to the weather, NOT by the calendar.
- Optimal temperature range for growing cauliflower is between 60°-65°. Plants will not grow well in temperatures above 75°. Although plants are frost tolerant, too many nights of low temperatures can lead to quality issues.
- Maintain consistent watering. Mulch around plants to help moderate soil temperatures and retain moisture.
- One to two weeks after planting out, start fertilizing with a naturally derived, water-soluble vegetable-specific food with a 2-3-1 formula. Continue once every two weeks until harvest.
- Utilize grow tunnels or floating row covers to help protect heads from sunburn, which leads to discoloration and bitter taste. Otherwise, some lower leaves must be pulled up and bound over the head to protect it, which is referred to as blanching. However, tunnels or row covers also help exclude insect pests.
- Cauliflower varieties mature to 6-8-inch heads or curds in 65-80 days. Monitor plants closely, as over-ripe heads can become pithy or grainy. When heads reach harvestable size, cut the entire center head while leaving some protective lower leaves. The remaining stems and roots can be pulled up and composted.
- Diseases common to other brassicas are possible but rare if proper crop rotation is followed.
- Insect pests common to cabbage and other brassicas are possible, like cutworms, cabbage worms, loopers, flea beetles, or aphids. Utilize bio-insecticides containing Bt, like Thruicide® for worm pests or Spinosad insecticides for beetles and such.
Varieties & Types
- White varieties are classic, mid to early-ripening types.
- Colored-headed varieties are popular and mid to late ripening.
- 'Fioretto 60' Hybrid forms small clusters of florets for cut and come again harvests rather than one dense, full head. Longer stems can be clipped for fresh eating, grilling, or roasting. Easy-to-grow cauliflower option.
- 'Veronica Romanesco' Hybrid is a unique, mid-season cross between broccoli and cauliflower with a mildly sweet but nutty flavor that is hard to describe. Lime green multi-pointed heads are best when harvested small (5-6 In.) but can grow up to 8 in. across. Tolerates warm weather better than others.