Romanesco broccoli. Image courtesy Hans Braxmeier from Pixabay.
  1. Broccoli has been bred and cultivated for its large flowering head, but the stalk and the leaves are edible too.
  2. Since broccoli is related to canola, it is also prone to a number of insect problems. Row covers are recommended to keep pests at bay. 
  3. Broccoli can be direct seeded into the garden in early spring, but it does better transplanted as seedlings. If you direct seed, hold off thinning until mid-June. Because of the intense insect pressure on brassicas in the prairies, some of the plants will be lost to insect damage, unless row covers are used.
  4. There are different forms of broccoli such as the tender spears of broccolini with small, loose florets, to cultivars with large sturdy, tightly packed heads.
  5. Romanesco broccoli (shown at right) is actually more closely related to cauliflower, but commonly listed with broccoli in seed catalogues which is why we've included it here. It originates from Italy where it was first noted in the 1500's. This plant is fractal in its growth habit and has a series of self-similar buds growing in a logarithmic spiral pattern. Look closely and you will see this spiral repeated within each of the indiviual buds. It is fascinating to look at and tastes just wonderful too.
  1. Brassica oleraceae is a wild mustard plant. This was a very diverse plant and growers nurtured groups of plants that focused on whichever part of the plant they wanted to eat. Over time, some people selected wild mustard plants with larger, underdeveloped flower stalks. Now we call those plants broccoli! Other growers focused on other parts of the plant. For example, growers favoring plants with larger and larger top buds eventually developed the plant we call cabbage and those favoring small side buds developed the wild mustard into Brussels sprouts. Since all brassicas come from the same basic wild mustard, they have common gardening needs. Other brassicas include kale, kohlrabi, broccoli, and cauliflower.
  2. Broccoli is an Italian word taken from the Latin word branchium which means arm, branch or shoot
  3. Broccoli did not become popular in American homes until the early 1900’s.

Source: American Botanical Council

Broccoli are classified as brassicaceae or brassica vegetables (cole crops) and belong to the mustard family of plants. Brassicaceae plants were formerly classified as cruciferous plants.  ‘Cruciferous’ because the petals of the flowers of these crops form a cross. 

Brassica vegetables include cabbage, broccoli, cauliflower, kale, kohlrabi, Brussels sprouts, radish, turnip, rutabaga, Chinese cabbage, mustard greens and mustard cabbage (bok choi or pak choi). Since all of these plants share a recent common ancestor, they all have very similar growing recommendations and problems.

While they are quite similar, there are some key differences. To ensure best success we've broken these into separate articles for easier instruction.

Broccoli are high in vitamins A, C, K, B6, folate, pantothenic acid and fibre. Check here for detailed information from the USDA National Nutrient Database for Standard Reference. Harvard School of Public Health recommends eating them no more than once a week.

The Canadian Food Guide recommends that roughly half of the food on your plate should be fruits and vegetables.

Canada Food Guide: What's On Your Plate?

Growing outdoors

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Brassicas grow best in well-draining, moist soil. You can improve your soil's ability to hold moisture by adding organic matter such as compost or aged, composted manure. Do not use fresh manure as a soil additive. If you think your soil needs remediation, see our Soils and soilless mixes page for detailed advice.

As a leafy vegetable grown its flower, they prefer full sun to produce well but can tolerate some light shade, although shade will slow size and maturity. They will not be successful in very shady areas.

Broccoli is best grown outdoors in the ground, be it in raised beds or unraised/ground level gardens if the soil is suitable. Smaller varieties are suitable for growing in containers outdoors. They are not typically suitable for most hydroponic, straw bale, or other alternative growing methods.

Broccoli can be direct seeded into the garden in early spring, but it does better transplanted as seedlings. Transplants can be grown in your own home or purchased from a local greenhouse.

Starting your own broccoli plants from seed

  • Start transplants about 5 - 6 weeks prior to transplanting out. You can transplant seedlings as soon as daytime temperatures reach 10°C and night temperatures are not below -2°C for several nights in a row. In Saskatoon, your plant out date is around May 13 so you can start your transplants around the first week of April.
  • Sow seeds 0.5 cm deep in a commercial soilless media containing peat moss or coir, perlite and vermiculite.  Soilless media provides a disease-free environment as well as excellent drainage to minimize root disease problems. Seed 2 - 3 seeds per pot and then thin to the strongest plant after they have grown their first set of true leaves. 
  • Use flats, pots or containers with bottom drainage holes. At a soil or media temperature of 24°C, brassica seeds will germinate in 5 or 6 days.
  • Good lighting is crucial for the growth of healthy seedlings. Brassica seedling transplants require a minimum of 14 hours of light each day.
  • Leave a fan blowing on your young seedlings as they grow to will help to grow heartier plants and to reduce some seedling diseases.
  • For more details, check out our article on growing your own transplants.

The ideal brassica transplant:

  • is approximately 10-15 cm tall.
  • is dark green in color, though the lowest leaves may be a lighter color.
  • has a good root system but is not root-bound (tight, hard ball of roots that do not break apart when gently massaged). 
  • has a stem that is strong and sturdy. The internodes (spaces between leaves along the stem) will be small.  Transplants that are too tall will tend to break and dry out more easily once planted out into the garden. Research has shown that stem diameter can be increased and height controlled by providing seedlings with constant air movement from an oscillating fan – or by lightly brushing seedling tops with a tea towel or stick at least 20 times daily.

Fertilizing recently planted seeds or young seedlings is not recommended. The first leaves that grow are not true leaves. They are "seed leaves" called cotyledons and are shaped like a capital B. All leaves that grow after these are true leaves. Once your seedling is mature enough to grow true leaves, you can begin to fertilize two times per week using 20-20-20 water-soluble fertilizer. Mix according to label directions.

Harden off transplants prior to planting out by moving them outdoors into a sheltered, frost-free location at least 3 days prior to transplanting.

Don't forget to label what you planted. It's also helpful to draw a map to help you track planting locations and success each year. This information is critical if you're rotating your crops to help prevent insect and disease issues.

Brassicas tend to attract cabbage moths and flea beetles. If you're planning to stay pesticide-free, it's important to use row covers to prevent insect damage. This is especially critical if you're located near canola fields. Row covers should be installed very soon after planting, long before the insects arrive.

If you have had cutworm problems in your garden, place a collar around your transplants right after planting. Make collars out of toilet paper rolls, or any tin can or plastic container such as a yogurt container with both ends removed. Insert the collar at least 5 cm in the ground to prevent cutworms from feeding on the stems of your transplants.

Timing

  • Broccoli may be direct seeded in the garden or planted as transplants. See our transplants tab for tips on growing or purchasing your own transplants.
  • You can transplant broccoli seedlings as soon as daytime temperatures reach 10°C and night temperatures are not below -2°C for several nights in a row. In Saskatoon, your plant out date is usually any time after May 13.
  • Transplants must be hardened off before transplanting outdoors. While mature brassicas are frost tolerant, young transplants are less so.

Planting instructions

  • When planting, cover the entire transplant “plug” or seed ball with soil to prevent the plant from drying out.  Exposed peat or coir within the plug will act as a wick, drawing water away from the transplant and drying out the root ball.
  • Gently massage the roots within the plug so that the roots will grow into the surrounding soil and not remain restricted within the ball.
  • Broccoli transplants should be spaced 30 - 45 cm apart within the row, allowing 60 - 85 cm between rows.
Here are cultivar recommendations from the North Dakota State University Cultivar Trials, as they share a similar prairie climate and soils. You may download their list here: North Dakota State University Vegetable Cultivar Recommendations for 2021
  • 'Green Magic', 'Packman'

The following cultivars are recommendations from the University of Saskatchewan vegetable program field trials;which were conducted from 1989 through 2016. Although this information is no longer current, some may find it useful.

  • 'Arcadia', 'Bravado', 'Beaumont', 'Belstar', 'Captain', 'Centura', 'Coronado', 'Coronado Crown', 'Diplomat', 'Elsinore', 'Emerald Crown', 'Eureka', 'Everest', 'Goliath', 'Green Belt', 'Green Gold', 'Green Magic', 'Ironman', 'Lucky', 'Major', 'Marathon', 'Maverick', 'Olympia', 'Patriot', 'Patron', 'Santa Antia', 'SBC-77540'
Care recommendations include:
  • Actively growing broccoli plants prefer 2.5cm moisture/week in well-drained soils.
  • Broccoli does best with regular water. It can be grown successfully most years without additional water though you can expect smaller plants as a result. Water will affect yields, so if you're using more intensive growing methods you will need to water.
  • Harvest the initial head in early to mid July to stimulate the side shoots to grow for a longer harvest. Cut just below the head at a slight angle and ensure that you leave 12 - 15 cm (5 - 6") of stalk with leaves intact to continue to grow. Depending on weather and growing conditions, you should be able to harvest smaller shoots a few more times. The new shoots will be smaller, but tender.
  • Pick weeds as they appear, especially those in the Brassicaceae family which attract the same insects: common pepper-grass, shepherd's purse, stinkweed, Argentine canola, ball mustard, dog mustard, flixweed, Polish canola, wild mustard and wild radish. 
  • To reduce weeding, apply a thick layer of mulch around your plants.

Broccoli is not suited to fall seeding.

Broccoli is best grown from transplants in the far north.

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Forgot what you planted? Not sure if it's a weed? Germination in broccoli

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Growing in containers and indoors

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Large-headed broccoli cultivars are not good candidates for container growing, whether indoors or out. Smaller varieties such as rapini, broccolini and zamboni would work in a container. Otherwise, smaller or leafy brassicas such as kale, bok choi, radishes or pak choi work very well instead.

Broccoli make a great option for microgreens so if you love the flavour of broccoli and want to enjoy it all winter, try your hand at broccoli microgreens.

Rapini, broccolini and zamboni are smaller types.

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Saving seeds

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Seeds are expected to be shelf-stable for one year from date of sale if purchased from a reputable retailer. If you wish to save your seeds beyond that, you should store them in the fridge in a jar. Seeds lose viability quickly if they dry out too much or get too warm.

The life expectancy of broccoli seed stored under favourable conditions is about three years.

Seeds stored under less favourable conditions will show poor germination after just a single year of storage. Beyond this, you can expect your germination rates to go down (ie. not all of your seeds will grow, but some might). To test your seeds, you can do a simple germination test. Follow the link for instructions. If you are still getting some seeds germinating, seed more thickly and thin any extra.

Seeds can be saved from open-pollinated or heritage type broccoli plants. Hybrid broccoli seeds will not be the same as the plant from which the seeds were harvested. 

Seed saving may be difficult as it relies upon the plant flowering, setting and maturing seeds in a short growing season. To save seeds, select one or two plants to flower and produce seed pods. Once the seed pods have dried (preferably while still on the plant), remove the plant from the soil and hang the plant upside down to dry. It may take 2 - 3 weeks for the pods to completely dry. 

Harvest

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Check your seed package for days to maturity which varies depending on if you are growing an early-. mid- or late-season cultivar. 

Broccoli can be harvested when they reach the desired size, are firm to the touch and feel dense. 

Harvest the initial head in early to mid-July to stimulate the side shoots to grow for a longer harvest. Cut just below the head at a slight angle and ensure that you leave 12 - 15 cm (5 - 6") of stalk with leaves intact to continue to grow. Depending on weather and growing conditions, you should be able to harvest smaller shoots a few more times. The new shoots will be smaller, but tender.

Use a sharp knife to cut the broccoli from the main stalk close to the base of the head.

Broccoli doesn't have a particularly high respiration rate. While it is important to keep them cool during harvest, as it is with most vegetables, it isn't critical.

Storage

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Broccoli can be stored in the refrigerator for a few weeks to a month (see below for details).

  • The ideal storage conditions is near 0˚C with high humidity. Your fridge is likely a few degrees warmer than this, but it will work as long as you manage the humidity.
  • To maintain adequate but not excessive humidity either poke a few holes in your bag (ok), or use a plastic bag meant for vegetables (better), or keep a few sheets of paper towel in the bag with them and switch the paper towels for new ones once they become too moist (best).
  • For detailed advice on other potential spaces or methods, see our cold storage page.
If you're hoping to store them longer than a month, you will need to use other preservation methods such as freezing, fermentingcanning or drying.

Cooking and preserving

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Dehydrating Cabbage

Alternative ways to eat common vegetables

 

Troubleshooting

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Broccoli require good, consistent growing conditions. Providing their water, light and soil needs are managed they don't tend to get a lot of issues.

Ensuring that you maintain healthy soil with adequate organic matter and use row covers to prevent insect problems will go a long way towards preventing most issues.

Planting transplants into cool soil can cause them to bolt.

Too much nitrogen fertilizer can cause broccoli to produce leafy growth at the expense of flowerbuds and/or cause hollow stems.

See the Common problems tab on this page for advice on other specific broccoli issues.

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