Growing Broccoli

Planting, Growing, and Harvesting Broccoli

Broccoli Florets

Broccoli is a sun-loving, cool-season crop that is best grown in the spring or fall. Here’s how to grow broccoli in your garden.

Broccoli is rich in vitamins and minerals, and is a good source of Vitamin A, potassium, folic acid, iron, and fiber. Because of this, broccoli has been dubbed the “crown jewel of nutrition.”

Did you know that broccoli, cauliflower, kale, cabbage, collard greens, kohlrabi, rutabaga, turnips, and Brussels sprouts all come from the same species of plant? These popular vegetables are all cultivars (cultivated varieties) of “wild cabbage,” Brassica oleracea.

With broccoli, you may even be able to get a continual harvest throughout the summer and fall if you practice succession gardening and you live in an area where the summer doesn’t get excessively hot.

Planting

How to Plant Broccoli

  • As a cool-season crop, broccoli can germinate in soil with temperatures as low as 40ºF (5°C), though most gardeners start broccoli indoors if growing it from seed. See our free online Planting Calendar for local seed-starting dates.
  • For outdoor spring plantings, sow seeds or set transplants into the garden 2 to 3 weeks before your last spring frost date. (See local frost dates here.) If you transplant, assume 10 less days for growth or the “days to maturity” given on the seed packet.
    • You may need to make use of a cold frame to protect young plants from frost.
  • For fall plantings, seed 85 to 100 days before your average first fall frost. If you live in a warm climate, a fall planting is best, as broccoli thrives in cool weather. Plant seeds in mid- to late-summer in most places.
  • Broccoli requires full sun and moist, fertile soil that’s slightly acidic. Work in 2 to 4 inches of rich compost or a thin layer of manure before planting. (Learn more about soil amendments and preparing soil for planting.)
  • Plant seeds ½ inch deep, or set transplants slightly deeper than they were grown originally.
  • Within a row, space your plants 12 to 24 inches apart with 36 inches between each row.
  • Space plants 12 to 24 inches apart, depending on the side heads you want to harvest.
  • If you overseed, you will need to thin seedlings to 12 inches apart to give room for the broccoli to grow.

Growing Broccoli

Care

How to Grow Broccoli

  • Fertilize broccoli three weeks after transplanting seedlings into the garden.
  • Provide consistent soil moisture with regular watering, especially in drought conditions. Some varieties of broccoli are heat tolerant, but all need adequate moisture.
  • Do not get developing broccoli heads wet when watering.
  • Roots are very shallow, so try not to disturb the plants. Suffocate weeds with mulch.
  • Mulch will also help to keep soil temperatures down.
  • Learn more about taking care of your broccoli plant.

Pests/Diseases

  • Flea Beetles
  • Aphids: Curling leaves may mean that the plant’s sap is being sucked by insects. Apply soapy water to all sides of leaves whenever you see aphids.
  • Downy mildew: Yellow patches on leaves are usually caused by moist weather. Keep leaves as dry as possible with good air circulation. Buy resistant varieties.
  • Cabbage loopers: Small holes on the leaves between the veins mean small green caterpillars are present. Look at the undersides of the leaves. Hand pick if the problem is small or control with Bacillus thuringiensis, a natural, bacterial pesticide. Use a floating row cover just after planting through harvest to prevent caterpillars.
  • Cabbageworms and other worm pests: Treat same as loopers.
  • Cabbage root maggots
  • Whiteflies
  • Nitrogen deficiency: If the bottom leaves turn yellow and the problem continues toward the top of the plant, the plants need a high nitrogen (but low phosphorus) fertilizer or blood meal. Blood meal is a quick nitrogen fix for yellowing leaves.
  • Clubroot: Quickly wilting plants may be due to this fungus in the soil. The entire plant, including all roots and root tendrils, must be gently dug up and removed. If the roots are gnarled and misshapen, then clubroot is the problem. Act quickly to remove the plants so that the fungus doesn’t continue to live in the soil. Do not compost the plants. Raise the pH of your soil to above 7.2. You may need to sterilize your soil, too.
  • Woodchucks 

Broccoli close-up

Harvest/Storage

Harvesting

  • In terms of timing: Harvest broccoli when the buds of the head are firm and tight, right before the heads flower. If you do see yellow petals, harvest immediately.
  • For best taste, harvest in the morning before the soil heats up.
  • Cut heads from the plant, taking at least 6 inches of stem.
  • Cut the stalk of the main head at an angle, about 5 to 8 inches below the head.
  • 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.

Storage

  • 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.

Spacing for Broccoli

Recommended Varieties

Wit & Wisdom

Recipes

Growing Broccoli

Botanical Name Brassica oleracea, Italica group
Plant Type Vegetable
Sun Exposure Full Sun
Soil Type Sandy
Soil pH Slightly Acidic to Neutral
Bloom Time
Flower Color
Hardiness Zones 3, 4, 5, 6, 7, 8, 9, 10
Special Features