How to Grow Broccoli Plants in Your Own Backyard, No Matter the Season

Beautiful green broccoli is one of the most versatile vegetables a backyard gardener can plant. It's delicious raw or cooked, easy to freeze and store, and it's ready to harvest often in fewer than two months.

It's also an adaptable part of your garden plan, able to be planted in summer for a spring harvest or in summer for a fall crop—and proper harvesting techniques let you extend the productivity of the plant over multiple weeks. Ahead, we spoke to experts about how to start, transplant, care for, and harvest this garden essential.

When to Plant Broccoli

Broccoli is a versatile vegetable that can be planted for harvesting in warm or cool weather. "Plant broccoli outdoors in early spring for a summer harvest or in late summer for a fall harvest," says Carrie Spoonemore of Park Seed. "Ensure the threat of frost has passed for spring planting or that there's enough time before the first fall frost for a fall planting."

For Spring Harvesting: "Transplant seedlings outdoors after the threat of frost has passed, and expect maturity in late spring to early summer," says Spoonemore. "Provide frost protection for young plants if late frosts are a concern, and ensure soil temperatures have warmed to around 50 to 60 degrees Fahrenheit before transplanting."

For Fall Harvesting: "Begin broccoli seeds indoors in mid to late summer, transplant seedlings outdoors about 10 to 12 weeks before the first expected fall frost date, and anticipate maturity in late summer to early fall," says Spoonemore. "Extra water may be necessary during the hot summer months to help seedlings establish, and protection from early fall frosts with row covers or other methods may be needed."

For Winter Harvesting: Broccoli is frost tolerant and is a great vegetable to grow in the winter. In regions with mild winters, broccoli seeds can be sown in the late summer or early fall for winter harvesting, generally around December. Broccoli can withstand temperatures as low as 26 degrees Fahrenheit, so with a little effort, you can keep broccoli going for much of the year, depending on your zone. Mulch the soil around your broccoli plants to keep the soil warm, and make sure to water regularly. If temperatures dip lower than the mid to low 20s, consider covering your broccoli plants with burlap or frost cloths.

How to Plant Broccoli Indoors

Choose a warm, sunny indoor space to start broccoli seeds indoors 6 to 8 weeks before your local last frost date for a spring planting, or in late summer for a fall planting. "Broccoli seeds germinate best at temperatures between 65 and 75 degrees Fahrenheit," says Spoonemore. She recommends using an indoor miniature greenhouse, like the Park Seed Bio Dome, but you can also get the seeds started with simple trays and small pots.

Materials You'll Need

• Seed-starting trays
• Small pots
• Seed-starting mix
  

Instructions

1. Fill each container with seed-starting mix to 1/2 inch below the top of the container, says Spoonemore. Moisten the mix evenly.
2. "For trays or pots, create small indentations in the medium of each," says Spoonemore. "Drop one or two broccoli seeds into each indentation. Check the medium’s moisture level regularly and water as needed to keep it consistently moist but not waterlogged."
3. Track the progress of your seeds. "Keep an eye on your seedlings as they grow," says Spoonemore. "Once they have developed their first true leaves and are large enough to handle, you can transplant them into larger pots or your garden."
4. Harden them off. Spoonemore recommends exposing broccoli seedlings slowly to the outdoors so the plants can acclimate to the change in temperatures. "Once they are hardened off, transplant them into well-prepared garden soil, spacing them according to the recommendations on the seed packet," she says.

How to Plant Broccoli Outdoors

Whether you decide to plant in early spring or late summer, choose a sunny part of your garden where you can plant the seeds in well-drained soil, says Spoonemore.

Instructions

1. Begin by removing weeds, rocks, and debris from the planting area. If necessary, says Spoonemore, "add compost to the soil to enhance its organic content and improve drainage."
2. Sow the broccoli seeds about 1/2 inch deep, leaving 3 inches between each plant and spacing rows 18 to 24 inches apart.
3. Water your broccoli seeds well. "After planting, water the soil thoroughly to settle it around the seeds or transplants," says Spoonemore. "Keep the soil consistently moist, but not waterlogged, throughout the growing season."
4. Add nutrients a few weeks later. "About three to four weeks after planting, side-dress the broccoli plants with a balanced fertilizer or compost to provide additional nutrients for healthy growth," Spoonemore says.
   

Care Requirements for Broccoli

To ensure a healthy broccoli crop, keep these care requirements in mind.

Sun

While broccoli plants will grow best in a full sun location, they can also tolerate partial shade, says Spoonemore.

Soil

For best results, plant broccoli in slightly acidic, fertile, well-drained soils, says Logan Minter, Ph.D, associate professor at The Ohio State University South Centers.

Water

Broccoli requires regular watering—but not overwatering. Keep the soil moist to at least 3 to 4 inches below ground.

Temperature

Broccoli grows as an annual in USDA zones 2 through 11, so it's hardy enough to thrive in a range of temperatures and climates. Plant seedlings after the last frost date in 50- to 60-degree Fahrenheit soil, says Spoonemore.

Fertilizer

Balanced fertilizer (or compost) can be applied to the plants for added nutrients about four weeks after planting, says Spoonemore.

How to Harvest Broccoli Plants

Depending on the variety of broccoli you plant and the growing conditions, the heads will be ready to harvest about 60 to 90 days after planting. "Harvest broccoli heads when they are firm, compact, and deep green, with florets just beginning to open but still tightly packed," says Spoonemore. Here's how Spoonemore recommends harvesting broccoli plants:

1. Cut the main head at an angle about 5 to 6 inches below the head to encourage side shoots for additional harvests.
2. Continue to monitor the plant for side shoots and harvest them when they reach a usable size, typically 3 to 6 inches long, using the same cutting technique. This allows for a continuous harvest over several weeks, maximizing the productivity of the broccoli plant.

Common Pests and Diseases

Broccoli plants can be damaged by common insect pests, like caterpillars, aphids, flea beetles, and harlequin bugs, says Minter. “Caterpillars are best treated by physically removing them. Insecticides can be effective on young caterpillars and aphids. The use of fabric row covers are sometimes used to prevent infestation, but caution should be used to ensure the fabric doesn’t lay wet against developing heads causing them to mold."

Use companion planting with broccoli to provide natural pest control. To minimize damage from pests and diseases—like blackleg, clubroot, and Sclerotinia white mold. Minter also recommends crop rotation. "Since broccoli is closely related (often adapted from the same species) as other cole crops (kale, cabbage, kohlrabi, Brussels sprouts, mustard greens), crop rotation is an important tool in insect and disease management,” he says.