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Growing Broccoli: Planting, Growing, and Harvesting Broccoli Plants | The Old Farmer's Almanac

Broccoli

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Botanical Name
Brassica oleracea (Italica group)
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Planting, Growing, and Harvesting Broccoli

Catherine Boeckmann
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Broccoli is a cool-season vegetable planted in spring. The deliciously tender spears of garden-grown broccoli are also incredibly good for you—the “crown jewel of nutrition.” See our guide (and new video) on growing broccoli from planting to harvest!

About Broccoli

The common type of broccoli we see in grocery stores is “Calabrese broccoli” (named after Calabria in Italy). Planted in mid-spring, this variety produces big green heads on thick stalks. 

Closely related to cauliflower, cabbage, brussels sprouts, and kohlrabi, this cole crop is worth growing for its nutritional content alone. It’s rich in vitamins and minerals as well as a good source of Vitamin A, potassium, folic acid, iron, and fiber. 

Broccoli takes a long time to mature, so be patient! Once you harvest the main head of a broccoli plant, it will often keep producing smaller side shoots that can be enjoyed for months to come.

Planting

Broccoli should be planted in a site that gets full sun (6 to 8 hours of sunlight per day). Lack of sunlight may produce thin, leggy plants and subpar heads.

Plant in a bed of moist, fertile soil that drains well. To increase fertility before you plant, in early spring, work in 2 to 4 inches of rich compost (humus) or a thin layer of manure. The soil pH should ideally be slightly acidic, between 6.0 and 7.0.

When to Plant Broccoli

  • Broccoli is cool-season crop, so it should be started in early- to mid-spring (depending on your climate) for an early summer crop, or in mid- to late summer for a fall crop. High temperatures will affect development of the broccoli head (the harvestable part), so the goal is to get broccoli to mature before or after high temperatures are expected.
  • Broccoli seeds are capable of germinating in soil temperatures as low as 40°F (4°C), but warmer soil is preferred and will greatly speed up development.
  • For spring plantings, broccoli may be started indoors or outdoors a few weeks ahead of your last spring frost date. Consult our Planting Calendar to see recommended dates for your area. Generally speaking:
    • Start seeds indoors 6 to 8 weeks before your last frost date.
    • Sow seeds outdoors 2 to 3 weeks before your last frost date, or as soon as the soil can be worked in the spring.
  • For fall plantings (best in warm climates), sow seeds outdoors 85 to 100 days before the first fall frost, when soil and ambient temperatures are high.

Spacing for Broccoli

How to Plant Broccoli

  • If starting seeds outdoors, sow seeds 1/2-inch deep and 3 inches apart.
  • Once seedlings reach a height of& 2 to 3 inches, thin them so that plants are 12 to 20 inches apart.
  • If you started seeds indoors, plant transplants that are 4 to 6 weeks old (and have 4 or 5 leaves) outdoors, 12 to 20 inches apart, in holes slightly deeper than their container depth. 
  • Space rows of broccoli 3 feet apart. (Closer spacing yields smaller main heads, but more secondary heads.)
  • Water well at the time of planting.

Video Demo of Sowing Broccoli

For those who wish to start sowing in pots, watch Ben in this video show you how it’s done! See the whole process from sowing to transplanting to broccoli care and harvesting.

Growing
  • Plants thrive in temperatures between 65° and 70°F (18° and 21°C).
  • Fertilize broccoli three weeks after transplanting seedlings into the garden. Use a low-nitrogen fertilizer, such as a 5-10-10 formula.
  • Thin when young plants reach 2 to 3 inches tall. Plants should be between 12 and 20 inches apart.
  • Provide consistent soil moisture with regular watering, especially in drought conditions. Water at least 1 to 1 1/2 inches per week.
  • Do not get developing broccoli heads wet when watering, as it can encourage rot.
  • Roots are very shallow, so try not to disturb the plants. Suffocate weeds with mulch.
  • Mulching around plants will also help to keep soil temperatures down.
  • Use row covers to minimize pests.
  • To promote the growth of a second head after the first has been harvested, maintain an active feeding and watering schedule.
  • Learn more about taking care of your broccoli plant.

Growing Broccoli

Harvesting
  • Harvest broccoli in the morning, when the buds of the head are firm and tight, just before the heads flower.
  • If you do see yellow petals, harvest immediately, as the quality will decrease rapidly.
  • Cut heads from the plant, taking at least 6 inches of stem. Make a slanted cut on the stalk to allow water to slide away. (Water can pool and rot the center of a flat-cut stalk, runing the secondary heads.)
  • Most varieties have side-shoots that will continue to develop after the main head is harvested. You can harvest from one plant for many weeks, in some cases, from spring to fall, if your summer isn’t too hot.
  • Learn more tips on harvesting broccoli.

How to Store Broccoli

  • Store broccoli in the refrigerator for up to 5 days.
  • If you wash before storing, make sure to dry it thoroughly.
  • Broccoli can be blanched and frozen for up to one year.

Close-up of broccoli heads

Wit and Wisdom
  • Originally, broccoli was eaten for its stems.
  • Early Roman farmers referred to broccoli as “the five green fingers of Jupiter.”
  • Once you’ve gotten broccoli down pat, why not try growing one of its relatives? See our Growing Guides for cauliflower, cabbage, brussels sprouts, rutabaga, kale, and turnips!
Pests/Diseases

Broccoli Pests and Diseases

Pest/Disease Type Symptoms Control/Prevention
Aphids Insect

Curled, misshapen/yellow leaves; distorted flowers/fruit; sticky “honeydew” (excrement); sooty, black mold.

Grow companion plants; knock off with water spray; apply insecticidal soap; put banana or orange peels around plants; wipe leaves with a 1 to 2 percent solution of water and dish soap (no additives) every 2 to 3 days for 2 weeks; add native plants to invite beneficial insects (such as ladybugs).
Cabbage loopers Insect Large, ragged holes in leaves from larval feeding; defoliation; stunted or bored heads; excrement. Handpick off plants; add native plants to invite beneficial insects; spray larvae with insecticidal soap or Bacillus thuringiensis (Bt)—a natural, bacterial pesticide; use row covers; remove plant debris at end of season.
Cabbage root maggots Insect White maggots become gray flies that resemble small houseflies. Wilted/stunted plants; off-color leaves; larvae feeding on roots. Use collars made of plastic or tin foil around seedling stems; monitor adults with yellow sticky traps; use row covers; destroy crop residue; till soil in fall; rotate crops.
Cabbageworms Insect Leaves have large, ragged holes or are skeletonized; heads bored; dark green excrement; yellowish eggs laid singly on leaf undersides. Handpick; use row covers; add native plants to invite beneficial insects; grow companion plants (especially thyme); spray Bt (Bacillus thuringiensis).
Clubroot Fungus Wilted/stunted plants; yellow leaves; roots appear swollen/distorted. Destroy infected plants; solarize soil; maintain soil pH of around 7.2; disinfect tools; rotate crops.
Downy Mildew Fungus Yellow, angular spots on upper leaf surfaces that turn brown; white/purple/gray cottony growth on leaf undersides only; distorted leaves; defoliation. Remove plant debris; choose resistant varieties; ensure good air circulation; avoid overhead watering.
Nitrogen deficiency Deficiency Bottom leaves turn yellow and the problem continues toward the top of the plant. Supplement with a high nitrogen (but low phosphorus) fertilizer or blood meal. Blood meal is a quick nitrogen fix for yellowing leaves.
Stink bugs Insect Yellow/white blotches on leaves; shriveled seeds; eggs, often keg-shape, in clusters on leaf undersides. Destroy crop residue; handpick (bugs emit odor, wear gloves); destroy eggs; spray nymphs with insecticidal soap; use row covers; weed; till soil in fall.
White rust Fungus Chalk-white blisters mainly on leaf undersides; small, yellow-green spots or blisters, sometimes in circular arrangement, on upper leaf surfaces; possible distortion or galls; flowers/stems may also be infected. More common with warm days and cool/moist nights.  Destroy infected plants; choose resistant varieties; weed; destroy crop residue; rotate crops.
Whiteflies Insect Sticky “honeydew” (excrement); sooty, black mold; yellow/ silver areas on leaves; wilted/stunted plants; distortion; adults fly if disturbed; some species transmit viruses. Remove infested leaves/plants; use handheld vacuum to remove pests; spray water on leaf undersides in morning/evening to knock off pests; monitor adults with yellow sticky traps; spray with insecticidal soap; invite beneficial insects and hummingbirds with native plants; weed; use reflective mulch.
Cooking Notes

One ounce of broccoli has an equal amount of calcium as one ounce of milk. Learn more about the amazing health benefits of broccoli

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