Broccoli is one of my favorite plants to grow and eat, and it’s one of the most nutritious crops there is. If you want to grow broccoli in your garden, here’s everything you need to know to keep it thriving from planting to harvest.
You can also download my How Do I Grow Broccoli? one-sheet and keep the free resource handy for your reference.
Broccoli is a cultivar of the species Brassica oleracea, which also includes cabbage, cauliflower, kale, collard greens and Brussels sprouts. Like its cousins, broccoli performs best in steady, cool weather. That’s why most commercially grown broccoli comes from the central California coast, where fields stay cool enough to grow it year-round. But no matter where you live, make this one of the first plants you grow in your cool-season garden. In fact, broccoli is sweetest when it matures in cool weather.
You get a lot of bang for your buck with broccoli since the entire plant is edible. In addition to the florets and stems, broccoli leaves and stalks also belong on your dinner plate. Broccoli can be steamed, roasted and even fried. It’s delicious with butter, grated cheese or cheese sauce.
Where, When and How to Plant Broccoli
Beginning gardeners or those who simply love the convenience of ready-to-plant seedlings may want to purchase broccoli starter plants at the garden center, but anyone can successfully start broccoli seeds indoors.
Broccoli seeds can be sown indoors in sterile seed-starting mix eight weeks before the last frost date. Plant seeds a quarter-to-half-inch deep and keep the soil moist. The seeds will germinate in 10 days to two weeks if the soil temperature is kept between 60° and 85°. Once the seeds sprout, thin to one seedling per cell. Keep the seedling under a grow light so they will not stretch out in search of sun.
Prior to planting the seedlings outdoors, harden them off. Put seedlings out for just a half-hour on the first day and add more time outdoors each day for a week until they are ready to handle eight hours of direct sunlight.
Three weeks before the last frost date, seedlings can be planted outdoors. However, if you use cold frames, cloches or row cover, you can plant outdoors even earlier — as many as three weeks earlier.
But no matter when you plant your broccoli starts in the garden, final spacing should be 12–18 inches apart in rows, with about 15 inches of space between rows.
Broccoli grows best in full sun, but a little shade can delay bolting in warmer months.
Broccoli prefers moist but well-drained soil with a pH between 6.0 and 7.0. Amending soil with compost and aged manure will improve drainage while also providing nutrients that broccoli needs.
All broccoli belongs to the same group of Brassica oleracea, italica, but there are still many, many varieties to choose from.
Belstar is a uniform broccoli with 6-inch, tightly inches heads of blue-green florets. It can be planted in both cool and warm weather successfully. It has good disease resistance and matures in 66–75 days.
Bonarda is a cold-hardy purple broccoli with narrow stems on upright plants. It is planted in late summer or early fall and then harvested in early spring.
Calabrese is an Italian heirloom that made its way to the United States in the late 19th century. The heads grow to be 5–8 inches and the plants produce many side shoots as well. Plants mature in 90s days.
De Ciccio is another old Italian heirloom. The vigorous plants produce blue-green heads that are 3–4 inches wide. The plants reach maturity at different times from one another starting in 60–70 days, for an extended harvest.
Emerald Crown is a compact plant with large domes of blue-green heads and sweet stalks. It does well in most regions of the United States and can be planted in spring or summer. It matures in 60–70 days.
Express has deep blue-green heads that can grow up to 7 inches across. The plants also produce tender side shoots with tasty florets. It can be planted in spring and summer, and matures in 75 days.
Gemini is a fast-growing variety that is ready to harvest in 50 days. The florets are light green and domed on 6-inch heads. Plant in spring or late summer.
Gypsy has a strong root system that helps it succeed in soil with below-average fertility. The heads are well domed, and the plants are resistant to downy mildew and heat tolerant. Gypsy matures in 60 days and is intended for summer harvest.
Purple Sprouting has sweet-tasting, loose purple florets that turn green when cooked. The plants are quite tall, between 24 and 36 inches, and are hardy to 10° and even colder. This open-pollinated variety takes 220 days to mature and is typically harvested in March or April.
Santee is another purple variety, though it’s a hybrid. Planted out in late summer or early fall, they will be ready to harvest in 80–115 days.
A total of one to two inches per week of water — including rainfall — is ideal for broccoli. A drip irrigation system is ideal for broccoli as it will keep the soil consistently moist. Applying 2–3 inches of organic mulch around the plants, such as shredded leaves or straw, will retain moisture between waterings while also suppressing weeds and keeping the soil cool.
In addition to improving soil fertility with compost and manure, I apply fish emulsion and blood meal to give the plants a boost and help my broccoli thrive throughout the season. These organic fertilizers won’t cause nitrogen burn the way that chemical fertilizers can.
The best way to know if your soil is giving broccoli what it needs is to get your soil tested through your county extension service.
Broccoli Pests & Diseases
When it comes to preventing broccoli pests, using floating row cover from the day plants go in the ground will make all the difference. Row cover is a barrier that prevents moths from laying eggs on the leaves, which become the pests most common to broccoli.
Because broccoli is a brassica, it is affected by the same pests as cabbage, such as cabbage loopers and cabbage worms. Be on the lookout for small white butterflies casing out your garden in mid-spring and early fall. These are cabbage butterflies, and they’re looking for a place to lay their eggs, which will become the worms.
For cabbage worms, cabbage loopers and other caterpillars, an effective biological control is Bacillus thuringiensis, or Bt. But you can also simply handpick caterpillars as you find them.
Another common broccoli pest is the flea beetle, a chewing insect. This small black or bronze jumping leaf beetle is just an eighth of an inch long. As with moths, floating row cover can keep flea beetles at bay. Another strategy is to plant a trap crop of radishes, which flea beetles prefer over broccoli.
Cabbage root maggots are fly larvae. Affected plants will wilt and have stunted growth. Again, a physical barrier is in order before the flies have the opportunity to lay their eggs.
Diseases affecting broccoli include Alternaria black spot, black leg, ring spot, Botrytis stem blight, clubroot and downy mildew. To lessen the occurrence of broccoli diseases, refrain from overhead watering. Wet foliage provides an ideal environment for many of these pathogens, so watering around the base of the plants is the preferred method.
The best control method for broccoli diseases is to remove the affected plants to reduce the spread. Pathogens can persist in soil for several years, so practice crop rotation — don’t plant any brassicas in the same spot for the next three years, at least.
The best time to harvest broccoli is when the unopened flower buds are just starting to swell. Harvest in the morning — when the moisture content is the highest — and cut the stalks several inches below the head at a 45-degree angle. After harvesting the main crown, you can expect to have several smaller crowns that will develop from side shoots and then consistently harvest these shoots to encourage even more production.
What are your secrets to grow broccoli successfully? Let us know in the comments below.
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Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Tomato expert Craig LeHoullier joins me in leading this course on how to grow healthier, productive tomato plants and how to overcome tomato-growing challenges.
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
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