This care guide provides a comprehensive introduction to growing Brussels sprouts, a winter vegetable that can withstand the harshest winter conditions and provide fresh and nutritious harvests. The guide covers choosing the right variety, preparing the ground, sowing indoors or outdoors, and transplanting the young plants to their final growing position. It also includes tips on caring for Brussels sprouts, such as watering, feeding, and pest and disease control. With the information provided in this guide, even beginners can successfully grow their own delicious Brussels sprouts.
Getting Started
Brussels sprouts are a winter vegetable that offers fresh, nutritious harvests even in the coldest weather. With modern varieties providing improved flavour, this versatile vegetable has gained popularity and is used in various dishes, not just the traditional festive feast.
Although slow-growing, Brussels sprouts are relatively easy to cultivate and provide valuable harvests through the colder winter months. As a member of the cabbage family, they are very hardy and can withstand the harshest winter conditions. Interestingly, sprouts have the sweetest flavour when harvested after being frosted.
Brussels sprouts form large, unique-looking plants that can grow up to 1m tall, featuring a leafy top and sturdy stem covered in small rounded green or purple sprouts. They take time to mature and should be sown from early spring onwards, ready for harvest from autumn to late winter, depending on the variety and sowing time. Although they do take up quite a lot of space for a considerable period, they crop well, providing valuable fresh harvests during the winter months.
Choosing Brussels Sprouts
If you’re interested in growing Brussels sprouts, there’s a wide range of varieties to choose from, including over 100 types of sprouts, as well as a sprout/kale hybrid called kalettes or flower sprouts. For the best results, it’s recommended to choose F1 hybrid varieties to ensure a consistent, high-yielding crop of tasty sprouts.
While Brussels sprouts have a reputation for being bitter, most modern varieties have been specifically bred to have improved flavour and sweetness. Look for varieties with an RHS Award of Garden Merit (AGM) to ensure a mild flavour and reliable crop, as these have been tested by experts.
Brussels sprouts are available in early, mid-, and late-season varieties. Growing a selection of these will allow you to harvest sprouts from autumn to late winter, or concentrate on mid- to late-season varieties for harvesting at Christmas and beyond when other vegetables are scarce. Since each plant can produce a large crop over several months, only a few plants are typically required.
Brussels sprouts plants are generally tall (around 3ft), but compact varieties are available that are better suited for windy locations, smaller gardens, and containers. They come in various colours, including traditional green and attractive purple varieties. Some varieties offer resistance to clubroot disease, while others can grow in partial shade as well as in full sun.
Prepare the Ground
To successfully grow Brussels sprouts, it’s important to choose a location that receives ample sunlight and has fertile, well-drained soil. Since Brussels sprouts grow into tall plants, it’s best to choose a sheltered spot to protect them from strong winds. If the soil is too acidic, applying lime can raise the pH to at least 6.5.
Before sowing or planting, ensure the ground is free of weeds and has plenty of nutrients. You can achieve this by digging in about two buckets of well-rotted manure or garden compost per square metre. Ideally, this should be done in autumn before planting to allow the ground to settle. If you’re unable to do this, ensure that the soil is firmly packed. Finally, incorporate a high potassium general fertiliser at a rate of three handfuls per square metre by raking it in.
Sowing Brussels Sprouts
To successfully grow Brussels sprouts, it’s important to give them a long growing season. You can start them off early either indoors or outside under cloches. It’s recommended to sow early, mid-season, and late cultivars to be harvested over the longest period possible.
Since Brussels sprouts are brassicas, they should be grown alongside other cabbage relatives in crop rotations. This helps to avoid the build-up of pests and diseases in the soil.
Sowing Indoors
If you’re sowing seeds indoors, for an early crop, it’s best to sow from February to April in modular trays in a greenhouse or cold frame. Once they’re at least 10cm tall, move the young plants outside after the last frost into their final growing position.
Sowing Outdoors
When sowing seeds outdoors, it’s recommended to sow from early March to May in the prepared ground under cloches or fleece if the weather is still cold. Traditionally, Brussels sprouts are sown in a separate ‘seedbed’ and then transplanted in early summer when more space becomes available. However, you may prefer to sow them directly into the final growing site to avoid transplanting.
If sowing in a seedbed, sow the seeds thinly, 1-2cm deep in rows 15cm apart. Thin out the seedlings to 7.5cm apart once they’re large enough to handle, removing the weaker ones.
If sowing in their final position, either sow as above or, to avoid transplanting, sow several seeds every 60cm, then thin out the resulting clusters to leave just the strongest seedling at each point. If clubroot has been a problem recently, sow in large containers of multi-purpose compost and choose shorter varieties. Protect seedlings from slugs and snails.
Young plants should be either transplanted to their final site in early summer or thinned out further to 60cm apart, moving the spare plants to form new rows. Space rows 75cm apart.
Transplanting Brussels Sprouts
To grow healthy Brussels sprouts, it is recommended to move the young plants to their final growing position between April and early June when they reach a height of 10-15cm. Here are the steps to follow:
- Before moving the young plants, water them well the day before.
- Prepare the growing site as detailed in the ground preparation guide, making sure to firm the soil well. Brussels sprouts grow into tall and top-heavy plants, so they need to be anchored well in the ground to withstand winter gales.
- Carefully lift the young plants, trying not to disturb their roots, and plant them in their new hole. Plant them more deeply than before, ensuring that their lowest leaves are at the soil surface so that they root deeply. Firmly pack the soil around the plant.
- To give the plants enough light and air, space them 60cm apart, with 75cm between rows. It is crucial to maintain this wide spacing to help the plants crop successfully and deter fungal diseases. Resist the temptation to plant them more closely.
- After planting, water the young plants thoroughly and continue to water them regularly, ensuring that the soil doesn’t dry out until they grow stronger.
- If you grow the plants from seed indoors or buy young plants, use the same planting method in early summer after hardening them off.
- Protect the plants from slugs and snails and deter cabbage root flies by placing a felt cabbage collar around the base of the stem.
Caring for Brussels Sprout Plants
To ensure the optimal growth of your Brussels sprouts, it is crucial to protect them from pests such as butterflies and pigeons. The best way to achieve this is by covering them with fine-mesh netting. Additionally, you should water them whenever the soil starts to dry out and support taller plants with canes to prevent them from bending or breaking. To promote their growth during the summer months, you should also feed them regularly. Lastly, it’s important to remove any fading leaves to maintain good airflow around the plants.
Watering
To ensure healthy growth, it is important to water your Brussels sprouts seedlings and young plants regularly. Make sure the soil never dries out completely. As the plants mature and become stronger, you can reduce the frequency of watering only during periods of dry weather. If there is no rainfall, it is recommended to water the plants every 10 to 14 days to maintain their growth.
Mulching
To aid in retaining soil moisture and discouraging weed growth, it’s recommended that you spread a generous layer of mulch around your Brussels sprouts. You can use well-aged manure or compost from your garden as an effective mulch.
Feeding
During the month of July, it’s recommended to add a nitrogen-rich fertiliser as a top dressing to your Brussels sprouts. One option is to use dried poultry manure pellets, applying them at a rate of 150g per square meter.
Weeding
To ensure optimal growth and development of your Brussels sprouts, it is important to keep the area surrounding your seedlings and young plants free from weeds. This will help minimise competition for essential resources such as light, water, and nutrients.
Supporting
Before the autumn gales arrive, it’s recommended to add extra support to your Brussels sprouts by mounding up soil around the base of their stems. Additionally, taller plants might require staking with a sturdy bamboo cane, particularly in exposed areas. This will help prevent strong winds from knocking over these top-heavy plants, which could loosen their roots and impede growth, or even topple them completely.
Harvesting Brussels Sprouts
To grow your own Brussels sprouts, sprouts will form at the base of each leaf and stalk up the stem. While early varieties can be harvested from autumn onwards, the main cropping season is through winter. This is because sprouts’ flavour is sweeter once they’ve been frosted.
Begin by picking the lowest sprouts first, when they’re about the size of a walnut, firm and still tightly closed. You can snap them off with a sharp downward tug, taking a few from each plant along the row, and remove the lower leaves at the same time. Check plants regularly, and pick the sprouts gradually as more form. Newer varieties tend to mature more uniformly, so you can harvest the whole stem if preferred.
You don’t need to harvest all the sprouts at once, especially in cold weather. You can leave the plants standing and pick the sprouts as you need them. Some varieties have better “standing ability” than others. But be sure to check plants often and harvest before the sprouts start to open or turn yellow.
Once the cropping is over, the mild-flavoured young leaves, or sprout tops, can be harvested too.
Brussels sprouts are rich in vitamins, antioxidants, and fibre. They can be cooked in many ways, including roasting, sautéing, and stir-frying. Be careful not to overcook them.
Fresh sprouts are best, but you can store them in a plastic bag in the fridge for several days. Alternatively, you can harvest whole stems and either stand them in water for a few days. Or hang them up in a cool, frost-free garage or shed. Then, you can pick the sprouts as needed.
Problems Growing Brussels Sprouts
If you’re planning on growing Brussels sprouts, you should keep in mind that they’re typically sturdy plants. But they can sometimes experience slow growth or yields.
Because Brussels sprouts belong to the brassica family, they are susceptible to a variety of pests and diseases that also affect cabbage, such as clubroot and cabbage root fly. To shield them from pests such as cabbage caterpillars and pigeons, it’s advisable to cultivate them under fine-mesh netting. Furthermore, it’s important to be mindful of cabbage whitefly and aphids, as they can pose a threat to your crops.
Conclusion
Growing Brussels sprouts is easy and rewarding. You can have fresh harvests throughout winter. Modern varieties offer better flavour and pest resistance. Start by choosing F1 hybrid varieties with an RHS Award of Garden Merit. Sow early, mid-season, and late cultivars for a longer harvest. Ensure the soil is weed-free, nutrient-rich, and well-drained. Pick a sheltered and sunny growing site. Follow these steps to enjoy a versatile and delicious crop of Brussels sprouts.
