Brussels Sprouts – a superfood

Photo by Jackie Bantle. Brussels sprouts in the garden on August 4th, prior to pinching off the growing point.

Jackie Bantle
Saskatchewan Perennial Society

As cooler temperatures bring us indoors and in closer contact with other humans at the start of flu season, many of us are looking for superfoods to boost our immune systems.  You may be familiar with the antioxidants found in blueberries, haskap and cranberries but were you aware of the cancer-fighting glucosinolates and immunity boosting Vitamin C in Brussels sprouts?  Brussels sprouts are considered a cold-weather super food.

Believed to be a descendent of Mediterranean kale, Brussels sprouts have a been popular vegetable for centuries, first gaining significant popularity in 13th century Belgium.  Like other members of the Brassica family (which include cabbage, broccoli and cauliflower), Brussels sprouts prefer growing temperatures around 20-25˚C for optimal growth.  However, unlike other brassica vegetables, Brussels sprouts require a long season to mature and must be transplanted in spring. 

Young Brussels sprout transplants look like any other cabbage, cauliflower or broccoli plant however, during the season, Brussels sprouts grow into 50-100cm tall stalks (depending on the cultivar).  Each stalk may produce 15-20 or more sprouts.

Brussels sprouts transplants should be started indoors, in spring, 6-8 weeks prior to transplanting out.  Seeds will germinate in 5 or 6 days after planting.  Supplemental light will be necessary to produce healthy, sturdy transplants.  Brassica transplants can be transplanted outdoors as soon as daytime temperatures reach 15°C and night temperatures are above 0°C.  Harden off transplants prior to planting out by moving them outdoors into a sheltered, frost-free location at least 3 days prior to transplanting.  Young brassica transplants that have been hardened off can withstand a few degrees of frost.

Brussels sprouts prefer full sun, rich healthy soil and about 2.5cm of water/week during the growing season.  By mid-season, there should be some sign of tiny sprouts forming in the leaf axils along the stem.  In order to get the modified leafy buds (sprouts) along the main stem to develop and enlarge, 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 best flavour, harvest Brussels sprouts after a fall frost (or two) of -3°C.  The cold temperatures sweeten the sprouts.  Brussels sprouts can withstand several hard frosts of  -4/-5ºC as long as day time temperatures allow plants to thaw during the day. Sprouts should be harvested when they are bright green and before they turn yellow. 

Harvest Brussels sprouts by removing the side leaves and cutting the stalks off just above the soil.  Remove any diseased or yellowing sprout leaves.  Store stalks and sprouts in plastic bags in the fridge for up to one week or remove sprouts from stalks and store sprouts in plastic bags in a fridge.  Ideal conditions for fresh Brussels sprouts storage is 1ºC and 80% RH.

For long term storage, blanch Brussels sprouts in boiling water for 4 minutes.  Remove from boiling water and immediately place in an ice bath.  Remove sprouts from the ice bath, pat dry and freeze in sealed plastic bags or containers.  Frozen sprouts can be stored for up to ten months. 

When cooking after freezing, do not allow sprouts to thaw before cooking.  Place frozen sprouts in sauté pan or oven directly from the freezer.  Overcooking tends to produce a mushy texture and excessive sulphur flavour.  Brussels sprouts are loaded with vitamin C, A, potassium, calcium and fiber.  Unlike many vegetables, Brussels sprouts contain protein (100g contains 3.4g of protein). 

Growing brassica vegetables like Brussels sprouts in an area where a lot of canola or mustard is grown on a large scale can be a challenge.  The large acreages of these two field crops attract a wide variety of Brassica pests and diseases to the Prairies.  Flea beetles, cabbage loopers, root maggots and club root are all possible problems with growing Brussels sprouts.  Be prepared to use crop covers or contact your local garden center for pest and disease control solutions.

This column is provided courtesy of the Saskatchewan Perennial Society (SPS; ). Check out our website ( or Facebook page (