Unlike its leafy cabbage cousins, broccoli is grown for its immature flower heads. The secret to growing broccoli is to encourage full, healthy flower heads but to harvest them before they mature (“bolt”) and lose flavor.
There are many varieties of broccoli to choose from, from the popular large-headed varieties to spicy broccoli Raab to Romanesco and sprouting varieties. Some types of broccoli focus on one main flower head, while others sprout smaller individual florets. Make sure you understand the growing habits of your variety of broccoli in order to harvest properly.
Broccoli Growing Conditions
- Planting: Broccoli is a cool-season vegetable that likes daytime temperatures in the 60s and can tolerate light frost and temps down to the 20s. Many gardeners plant broccoli in early spring for the main harvest, then leave the plants growing over the summer for a second harvest in the fall.
- Summer Heat: Broccoli will “bolt” (go to seed) in hot weather, which results in a loss of flavor and toughening of texture. Some varieties are more heat-tolerant than others.
- Light: Broccoli needs full sun, at least 4-5 hours per day.
- Soil: Broccoli likes rich, well-draining soil with a pH around 6. Because of the short growing season, broccoli is in a race against time and needs high-quality soil amended with plenty of rich compost. To improve drainage, you can plant your broccoli in mounds.
- Fertilizer: Broccoli benefits from regular applications of organic fertilizer.
- Harvesting: Broccoli seeds take 3-4 months from planting to harvest while transplants take 2-3 months.
Broccoli Planting Tips
- Seeds: Unless you start seeds indoors over the winter, it may be difficult to grow a spring broccoli crop from seed, because the weather will warm too quickly. Fall crops are much easier to start from seed directly in the garden. Plant broccoli seeds about ¼ to ½ inch deep, and transplant to the garden in about 5 weeks.
- Transplants: Plant broccoli seedlings as soon as the ground can be worked in spring. If you’re planting broccoli transplants or seedlings, set them a little deeper in the soil than they were in the pot.
- Spacing: Space broccoli plants about 18 inches apart.
- Successive Plantings: Although the growing season is short for broccoli, you may be able to stagger plantings every 2-3 weeks for a longer harvest.
Broccoli Growing Tips
- Feeding:Broccoli grows in a hurry, and it needs a lot of nutrients. Rich compost will help feed your hungry broccoli, but it will also benefit from applications of compost tea or from monthly applications of a balanced organic fertilizer.
- Watering:Like other veggies, broccoli needs to be kept evenly moist. Give broccoli about an inch of water per week, and water deeply (rather than sprinkling) to encourage deep roots, but don’t let your broccoli plants become too dry between waterings.
- Diseases & Pests:Broccoli isn’t plagued by many diseases. The most common insect pests are aphids, cabbage worms, and slugs.
- Bolting:When growing broccoli in the spring, you’re in a race with the weather to keep your plants from going to seed. Hot soil is the culprit, so take steps to keep the soil cool for as long as possible. Mulch, regular water, and shade covers can prolong your broccoli season, and as the weather warms you should harvest more frequently to keep your plants from shifting into seed mode.
Broccoli Harvest and Use
- When to Harvest:When the main broccoli head is several inches in diameter, your broccoli is ready to harvest. The heads should be green, compact, and firm. If your broccoli plant produces side shoots, those florets may be smaller (but just as yummy). If left unharvested, broccoli heads will loosen and open into yellow flowers – if this happens, it’s too late.
- How to Harvest:Using a sharp knife, cut the main stalk of the broccoli at an angle, several inches below the flower head. Continue caring for the broccoli plant – it will likely begin producing side shoots and more broccoli!
- Storage:Fresh, dry broccoli will last in the fridge about 5 days in a non-airtight container. Wash broccoli immediately before use.
- Freezing:Broccoli freezes well. Cut the florets into pieces, then blanch the fresh broccoli by submerging it in boiling water for one minute, then plunging it into ice water to cool. Drain and dry, and pack the broccoli into airtight plastic bags.