Broccoli is an edible flower. Broccoli is a cool-season crop. Grow broccoli so that it comes to harvest when temperatures average no more than 75°F (23°C) each day.
Broccoli heads are clusters of tightly packed flower buds waiting to open. Broccoli is a hardy biennial, grown as an annual. It is a member of the cabbage or cole family. The flower stalks are green, purple, or white. The flowers are all yellow, but they are commonly eaten before they open, while they are still in bud, and before they bloom.
Plant broccoli in late winter or early spring for spring and early summer crops. Plant broccoli in mid to late summer or early fall for late winter or early spring crops.
Broccoli is a cut-and-come-again crop. Instead of cutting the whole plant to the ground at harvest time, cut only the main head. When the main head is removed, the plant will grow more side sprouts at leaf joints. Side sprouts of smaller heads provide a second and sometimes a third harvest from each plant.
Broccoli is a common dinner side dish. It is rich in vitamins A, B, and C, as well as calcium and phosphorus. Broccoli florets and stalks (with pithiness peeled away) can be eaten raw, steamed, or stir-fried. Broccoli florets are tasty with a dash of lemon juice or a topping of melted cheese. Use raw broccoli in salads or with dips. Steam broccoli or use it in stir-fries or cream soups or add broccoli to casseroles.
Here is your complete guide for growing broccoli.
Broccoli Quick Growing Tips
- Start broccoli seed indoors 5 to 6 weeks before the last frost in spring for spring planting.
- Start broccoli in the garden in mid to late summer to grow a late fall or early winter crop. In mild winter regions, plant in fall for winter harvest.
- Transplant broccoli seedlings to the garden when they are 4 to 6 weeks old, as early as the last frost in spring, after hardening off the seedlings for 4 days.
- In mild-winter regions, start seeds indoors in late summer and set them in the garden in autumn for winter harvest.
- Broccoli will come to harvest in 55 to 85 days when grown from transplants and 70 to 100 days when grown from seed.
Broccoli Yield. Plant 2 to 4 broccoli plants for each household member.
Broccoli Planting Time
- Broccoli is a cool-weather crop that must come to harvest before temperatures rise consistently above 75°F (24°C).
- Broccoli is commonly grown from transplants set in the garden. Broccoli will germinate in soil as cool as 40°F.
- Start broccoli seed indoors 5 to 6 weeks before the last frost in spring.
- Transplant broccoli seedlings to the garden as early as 4 weeks before and 2 to 3 weeks after the last frost in spring after hardening seedlings off for 4 days.
- For best growth, set transplants in the garden after the soil has warmed to 60°F.
- In mild-winter regions, start seeds indoors in late summer and set them in the garden in autumn for winter harvest. Whether that is too cold or too warm will cause broccoli to go to seed without forming heads.
- In cold winter, short-season regions start broccoli in summer for fall harvest.
- As a general rule, start a fall crop 18 weeks before the first expected frost.
- Broccoli grows best where air temperatures range between 45° and 65°F (7.2-18°C).
- Broccoli is frost-hardy and can tolerate temperatures as low as 20°F (-6.7°C).
Where to Plant Broccoli
- Plant broccoli in full sun.
- Broccoli grows best in nitrogen-rich soil that is well-drained soil.
- Add plenty of aged compost or well-rotted manure into the soil 2 weeks before planting. (Fresh manure can be added to soil in the fall for spring planting.) The addition of aged compost and aged manure ensures fertile soil.
- Broccoli wants a soil pH between 6.7 and 7.2. Add lime to the soil to achieve a higher pH if clubroot disease is a problem. (Lime inactivates the clubroot organism.)
- In regions where there is heavy rain or sandy soil, aged compost should be added to the soil to supplement soil nitrogen.
More tips: Broccoli for Cool Weather Harvest.
Planting and Spacing Broccoli
- Sow seed ½ inch deep and 3 inches (7.6cm) apart.
- Plant transplants that are 4 to 6 weeks old with four or five true leaves.
- Leggy transplants or transplants with crooked stems can be planted up to their first leaves so that they will not grow top-heavy.
- Plant seedlings 18 to 24 inches (45-61cm) apart in rows 24 to 36 inches (61-91cm) apart.
- Plant seeds and transplants at the same time for succession crops or plant early and midseason varieties at the same time.
- Transplant thinned seedlings to another part of the garden.
- Thin plants when they are 1 inch tall; cut thinned plants off at the soil level with a scissor.
- Place cutworm collars around young seedlings.
More tips: Broccoli Seed Starting Tips.
Broccoli Companion Plants
- Good companion plants for broccoli are beets, celery, herbs, onions, and potatoes. Avoid planting broccoli near pole beans, strawberries, or tomatoes.
- Broccoli grows to about 2 feet tall and wide; broccoli requires a good amount of space. During early growth, fill the space between broccoli plant with quick-growing vegetables such as lettuce and radishes.
Container Growing Broccoli
- One broccoli plant will grow in an 8-inch (20cm) container.
- Grow multiple plants in larger containers set 18 inches (45cm) apart.
- Broccoli is very sensitive to heat so be sure to move plants into the shade on hot days.
Four Stages of Broccoli Growth
Broccoli has four stages of growth:
- The rapid growth of leaves.
- Formation of the head (flower bud), the part that is eaten.
- Resting period while the embryonic blossoms are being formed.
- Development of the stalk, flowers, and seeds.
Head formation is essential for the production of the vegetable we eat. Broccoli that is hit by severe frost, lack of moisture, or too much heat will bolt–produce flower petals and seed–before the head of tight buds is formed.
- Broccoli needs a regular supply of water to produce good heads. Keep soil moist during the growing season. Soil moisture can be measured with your index finger: stick your finger into the soil, if it comes away dry, it is time to water.
- Water broccoli at the base of the plant.
- Give broccoli from 1 inch to 2 inches of water each week. One inch of water equals 16 gallons (60.5 liters).
- Excessive moisture can stunt or kill broccoli. If the soil tends to get waterlogged, plant broccoli in a raised bed.
- Decrease watering when plants approach maturity.
- Mulch around broccoli with straw or grass clippings to keep soil moisture even and the temperature down. Apply 4 to 6 inches of mulch.
- For a fall crop use a living mulch, underseed with clover, oats, or rye.
- Give broccoli a nitrogen boost after about three weeks of growth; side-dress broccoli with rotted manure or compost or apply manure tea.
- Side dress plants with well-aged compost at planting time and again at midseason.
- Keep broccoli planting beds weed-free. Weeds compete with broccoli for water and nutrients.
- Protect young plants with cutworm collars.
- After harvest, pull up the entire plant and compost it.
- Remove all crop residue from the planting bed before winter and gently turn the soil to expose insect larvae to winter cold temperatures.
- Broccoli can be attacked by cutworms, cabbage loopers (caterpillars preceded by small yellow and white moths), imported cabbage worms, cabbage root maggots, slugs, and aphids.
- Place a protective collar around young plants to exclude cutworms.
- Handpick loopers and worms destroy them or spray with insecticidal soap or Bacillus thuringiensis.
- Cabbage maggots are the larvae of a fly. Plant radishes near broccoli to repel the flies. Place row covers over seedlings or set plants through the garden fabric to keep flies from laying eggs in the soil. Mound diatomaceous earth or hot pepper around stems if maggots are in the soil. You can also mix wood ash into the soil near the roots.
- Cutworms and flea beetles will attack young plants.
- Flea beetles nibble holes in young leaves; attacks are worse in dry weather; keeping the soil moist will deter attacks.
- Mealy aphids are gray-green, waxy-looking aphids that suck juices from leaves; squash by hand or introduce ladybugs into the garden.
- Cabbage whitefly is a small white insect; spray with insecticidal soap or Bacillus thuringiensis.
- Caterpillars are the larvae of various types of cabbage white butterflies and moths; these pests eat holes in leaves; insecticidal soap or Bacillus thuringiensis.
- Cabbage root fly: these adult flies lay eggs at the base of young brassica plants; hatched grubs tunnel into roots causing plants to collapse; exclude the flies with row covers; dig up and dispose of collapsed plants.
- Slugs and snails eat ragged holes in leaves; handpick and destroy these pests.
- Birds can attack young seedlings; protect seedlings with netting or row covers.
- To deter insect pests, plant thyme alongside broccoli in a row about 6 inches away. You can also spray plants with a mix of boiled onion and garlic.
- Introducing beneficial insects such as lady bugs and green lacewings can keep pest insects under control.
- Broccoli is susceptible to cabbage family diseases including yellows, clubroot, and downy mildew.
- Plant disease-resistant varieties, rotate crops each year, and keep the garden free of debris to cut back the incidence of disease.
- Remove and destroy infected plants immediately.
- Black rot, also called blackleg, clubroot, and yellows are fungal diseases that can attack cabbage
- Blackleg leaves yellow, V-shaped lesions on leaf edges. Plants with clubroot wilt and look stunted; there will be galls on the roots. Cabbage yellows are marked by the yellowing of lower leaves.
- Blackleg, bacterial blight: control diseases through crop rotation; collect and burn or dispose of in the trash can plant material after harvest.
- Clubroots is a soil-borne disease that results in root swelling followed by yellow leaves, the collapse of the plant, and death. Lift the entire plant and dispose of it in the trash or burn it; do not compost diseased plants
- Downy mildew and yellows can also afflict broccoli plants.
- To avoid fungal diseases plant disease-resistant varieties or seeds that have been hot water treated. Plant in well-drained soil. Water with compost tea.
- Remove and destroy diseased plants immediately.
- Rotate crops on a three-year cycle.
More on broccoli pests and diseases: Broccoli Growing Problems: Troubleshooting.
Extending the Broccoli Season
- The broccoli season can be extended in several ways:
- For an early crop, start plants indoors 10 weeks before the last expected frost. Set plants into the garden in about 5 to 6 weeks.
- Cultivars such as ‘Green Valiant’ can withstand temperatures as low as 20°F. If the weather vacillates between cold and warm, a frost of 27°F will freeze plants.
- Where temperatures are greater than 40°F in winter, grow broccoli as a winter crop.
- A few days after the harvest of the main flower head, side shoots–smaller versions of the central head will begin to grow where leaves join the stem. Side shoots are a second crop. None of the side shoots will grow as large as the first head.
- Broccoli grown from seed will come to harvest in 80 to 150 days depending on the variety.
- Grown from transplants broccoli will come to harvest in 55 to 80 days.
- Cut closed flower heads with a sharp knife when they are still green and tight. Cut the central head leaving five to six inches of stem to stimulate many more small broccoli heads to develop. The size of the heads will decrease but they will still be edible.
- Small clusters will grow in the angles of the leaves and can be harvested later. Four to six cuttings of side shoots per plant will follow over several weeks. Harvest side shoots every few days; cut them regularly and the plant will continue to make new shoots. Four to six additional cutting of side shoots can occur.
- Heads that have begun to open showing small yellow flowers are past the eating stage.
- Stems are edible, but they should be peeled to remove the tough outer skin.
- Broccoli leaves are edible but they are tough and best used in soups.
- Soak broccoli heads in salt water (1 to 2 tablespoons of salt per gallon of water) for 30 minutes before cooking or storing; this will drive out any cabbage worms hiding in the heads.
More harvest tips: How to Harvest and Store Broccoli.
- Broccoli will keep in the refrigerator for up to one week if wrapped in plastic.
- Broccoli can be frozen after blanching. Frozen broccoli will keep for up to 3 months.
- Broccoli can be canned, frozen, or pickled.
Broccoli in the Kitchen
- Broccoli can be served with cheese or Hollandaise sauce.
- Florets can be broken and used in a salad or with a dipping sauce.
- Stalks can be parboiled and ten sauteed in oil with a little onion and garlic.
- To make sure broccoli stems are cooked adequately, stand stalks in a tall pot so the stem boil and the top steam.
- Purple broccoli turns green when cooked.
Broccoli Frequently Asked Questions
Q: What are the small yellow and white moths flying around my broccoli?
A: These are adult cabbage loopers and imported cabbage worms; the moth lay eggs and caterpillars hatch and eat leaves and flower buds.
Q: What causes broccoli flower heads to be loose and have little yellow flowers?
A: Loose heads with premature flowering are usually the result of weather that is too warm. Plant broccoli earlier in spring.
Q: Can I eat broccoli leaves?
A: Yes, broccoli belongs to the cabbage family and its leaves taste like cabbage, collards, or kale.
Q: Should I tie the leaves of broccoli over its head like I do with cauliflower?
A: No. The leaves of cauliflower are tied over the heads to reduce light and keep the flower heads white–called blanching. Broccoli flower heads do not need to be blanched.
Broccoli Varieties to Grow
- ‘Calabrese’: bluish-green central head with many side shoots; 85 days from seedlings.
- ‘DiCicco’: flat, dark green heads to 4 inches across; produces many side shoots; old-time favorite; 70 to 80 days to harvest from seedlings.
- ‘Green Comet’: blue-green heads grow 6 to 7 inches across; All-American Selection; 55 days to harvest from seedlings.
- ‘Packman’: central head and good side shoots; 60 to 80 days to harvest.
- ‘Premium Crop’: blue-green central, no sideshoots; grow to just 18 inches tall; disease resistant; 58 to 82 days to harvest.
- ‘Romanesco’: pale green, large head on a large-leafed plant; 85 days to harvest.
- ‘Royal Cruiser’: sideshoots almost as large as main heads; 85 days to harvest.
- ‘Spartan Early’: dark green heads reach 7 inches across; short, stocky plant; good production of lateral shoots after central head is cut; 58 days to harvest from seedlings.
- ‘Waltham 29’: blue-green heads are 5 to 6 inches across; poor side shoot production; best for fall planting; 74 to 85 days from seedlings.
- ‘White Sprouting’: many creamy yellow buds on a large plant; 70 days to harvest.
More Broccoli Varieties. ‘Arcadia’ (63 days), ‘Bonanza’ (55 days), ‘Citation, DeCicco’ (48 days), ‘Early Dividend’, ‘Emperor’ (80 days), ‘Eureka’ (87 days), ‘Green Comet’ (78 days), ‘Green Goliath’ (75 days), ‘Green Jewel’, ‘Green Valiant’ (70 days), ‘Gypsy’ (58 days), ‘Happy Rich’ (55 days), ‘Italian Sprouting’ (80 days), ‘Land Mark,’ ‘Legend’ (86 days), ‘Love Me Tender’, ‘Marathon’, ‘Minaret’, ‘Packman’ (80 days), ‘Paragon’ (75 days), ‘Pinnacle Premium Crop’ (58 days), ‘Late Purple Sprouting’ (220 days), ‘Raab Spring, Rapine’ (70 days), ‘Romanesco’ (70 days), ‘Saga’ (57 days),’ Salad’, ‘ShoGun’ (93 days), ‘Small Miracle’, ‘Sprinter, Super Blend’, ‘Super Dome’, ‘Thompson’, ‘Violet Queen’ (70 days), ‘Waltham'(95 days).
- Sprouting broccoli (Brassica oleracea, Italica group) produces longer stems and small clusters of buds, rather than larger heads.
- Broccoli raab or broccoli rabe (B. rapa, Ruvo group) is a turnip raised for its leaves, young, stems, and bud clusters.
Saving Broccoli Seed
- Broccoli, cabbage, kale, Brussels sprouts, can cauliflower are all bee-pollinated. They all belong to the same family and can cross-pollinate.
- Save broccoli seed only if you are growing a specific variety alone or if different varieties and species are widely separated.
- Broccoli is a biennial so you have to wait for the second year of growth for the production of seeds. Fall planted broccoli makes seed the next spring.
- Broccoli seed is viable for up to 5 years.
Broccoli is a hardy biennial grown as a cool-season annual. It grows 18 to 36 inches (45-91cm) tall or more and has broad, thick leaves and a thick main stalk. Broccoli forms single or multiple flower “heads ” of tiny blue-green flower buds. The flower heads are eaten before they bloom; buds open to tiny yellow flowers. Broccoli will bolt and go to seed in warm temperatures or when daylight hours lengthen.
Common name. Broccoli, Italian broccoli, Calabrese (British), brocks.
Botanical name. Brassica oleracea italica
Family: Brassicaceae (Cruciferae); other brassica plants include cabbage, kale, Brussels sprouts, cauliflowers
More tips: Planting Broccoli.