Brussels sprouts are one of those vegetables that may not be your favourite but are packed with vitamins and antioxidants that are good for you. They were not one of my favourites until my friend prepared them fresh from the garden. Fresh from the garden and roasted just right, brussels sprouts are delicious.
Brussels sprouts belong to the Brassica family of plants, i.e. the mustard family. All of the plants found in this family have a peppery/mustard flavour when eaten (cabbage, broccoli, cauliflower, kale, kohlrabi, Brussels sprouts, radish, turnip, rutabaga, Chinese cabbage, mustard greens and mustard cabbage (bok choi or pak choi)). Of all of the plants in the brassica family, brussels sprouts are one of the more difficult crops to grow in the garden. Not only do brussels sprouts require a long season, but they also require some extra care in late summer to ensure that the sprouts form on the stalks.
Brassica crops are one of the crops that are ideally suited to growing in a northern climate. Most of these crops prefer temperatures around 20-25 C for optimum growth and can easily mature during our growing season. However, if the ‘time to harvest’ on the seed packet is recommended to be longer than 90 days, that cultivar should be transplanted to ensure it will be mature before winter freeze-up in fall. Most Brussel sprout cultivars need more than 90 days to produce sprouts and these must be transplanted to produce sprouts during the relatively short Saskatchewan growing season.
Seed Brussels sprouts indoors approximately six weeks before transplanting out: an April 1 seeding will produce transplants for May 14. Harden off transplants before planting out. Brussels sprouts can withstand a few degrees of frost, don’t worry if they experience a light frost in spring.
Many gardeners become frustrated trying to grow brussels sprouts because the sprouts in the leaf axils don’t size up by harvest time. To produce good-sized ‘sprouts’ along the main stems, the growing point of each plant should be removed during the 3rd week in August. Simply break off the top 1cm of the plant. Instead of continuing to add growth on the top, the plant will put its energy into developing the sprouts along the side of the stem. By early October, the sprouts should be a good size for harvest.
For the best flavour, harvest brussels sprouts after a fall frost (or two) of -3 C. Mature Brussels sprouts can withstand frost temperatures of 4-5 C below freezing.
Pests
If you are trying to grow brassica vegetables in an area where there is a lot of canola or mustard grown on large-scale farms, controlling pests can be a significant challenge. Flea beetles are one of the earliest pests of brassica plants. Flea beetles are tiny black flies (approximately 2mm in length) that jump from plant to plant and feed on leaves, giving a shot-hole appearance to stems and leaves. They are especially devastating to young seedlings by completely devouring tiny cotyledons and first true leaves as they appear. Cover emerging seedlings with thin crop covers for protection.
Cabbage loopers can damage young and mature brassica plants. Cabbage loopers are the fleshy, green caterpillars that can be found in the leaf axils of the Brussels sprouts. Not only do they chew holes in the leaves of the plant but their green mushy excrement can be found throughout the crevices of leaves and heads. The adult form of the cabbage looper is the small white butterfly often found flying around the garden. These butterflies lay their yellow-colored eggs on the underside of leaves which then hatch into the caterpillars. Covering plants with thin supported crop covers will prevent butterflies from laying their eggs on plants. Bacillus thuringiensis (Bt) is a type of bacteria that is not harmful to humans and can be sprayed on the plant to control loopers. Check with your local garden centre for available products.
Root maggots are a huge problem in all brassica vegetables. Pupae overwinter in the soil. Grey-black flies emerge from the soil and lay eggs at the base of plants. The first round of egg-laying occurs from late May to early June. Shortly after eggs are laid, white maggots hatch and attack the roots of the young plants. Brassica plants affected by root maggots will appear stunted. Older leaves will turn yellow or purplish-red and then eventually die. Affected plants can easily be pulled out of the ground since the roots have been eaten off by maggots. In severe cases, the maggots will be visible. A second flush of flies and maggots occurs in mid-late August. Cover plants with crop covers to prevent flies from laying eggs at the base of the plants later in the season.
Cooking with brassica vegetables can be odorous but also provides an excellent source of vitamins and nutrients. Four to five minutes of steaming optimizes the level of the anti-cancer compound sulforaphane in brassica vegetables. If you’re on the fence about brussels sprouts, try roasting them with a lemon, thyme and parmesan seasoning – that might change your mind.
This column is provided courtesy of the Saskatchewan Perennial Society (SPS; [email protected]). Check our website (www.saskperennial.ca) or Facebook page (www.facebook.com/saskperennial) for a list of upcoming gardening events.
