How to Grow Brassicas: A Beginner’s Guide
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Brassicas are a powerhouse group of vegetables that include some of the most nutrient-dense and garden-friendly crops out there. From kale and broccoli to cabbage and cauliflower, these cool-season veggies are staples in both the kitchen and the garden! If you’re new to growing brassicas, or are wanting to level up your success for the upcoming fall gardening season, this guide will help you get started.
What Are Brassicas?
To start – what are brassicas? Brassicas, also known as cruciferous vegetables or members of the cabbage family. I’m sure you recognize many of them, including:
Cabbage
Cauliflower
Broccoli
Brussels Sprouts
Collard Greens
Kohlrabi
Turnips
Brassicas thrive in cooler temperatures and are often grown in spring or fall (my personal favourite is in the fall, the flavour is incredible!) They're prized for being rich in a plethora of health benefits and the structure they bring to a garden bed.
When to Start Brassica Seeds
Timing is key when it comes to planting brassicas in your garden.
Spring Crops: Start seeds indoors approximately 4-6 weeks before your last expected frost date. Once your seedlings are established, transplant them into the garden 2-3 weeks before the last frost, once they’ve grown strong enough and have at least 4-6 true sets of leaves. Alternatively, you can direct sow early spring.
Fall Crops: For a fall harvest, start seeds (either indoors, or directly sow in the garden) 10-12 weeks before your first fall frost. Fall is often the preferred season for many gardeners, myself included, for growing brassicas because the cooling temperatures reduce the amount of pests the crops are exposed to, and enhance flavour.
Example for zone 9a (like Saanich, BC): Start fall brassica seeds indoors in late June to early July and transplant outdoors mid to end of August for a robust fall harvest.
When and How to Plant Brassicas
Once your seedlings are ready, harden them off by gradually exposing them to outdoor conditions over the course of at least one week. Transplant your seedlings into rich, well-draining soil enriched with compost.
Planting Tips:
Spacing: Most brassicas will need 12-24 inches between plants, depending on the variety. I typically don’t follow spacing too closely, but it’s important that they do have enough room to grow. If you’re planting turnips, they can be planted 3-4 inches apart.
Soil: Plant in soil that’s fertile, slightly acidic to neutral (pH 6.0–7.0), and full of organic matter like compost.
Sunlight: Brassicas will do best in full sun (6-8 hours daily).
Water: Keep soil consistently moist, but not soggy.
Common Brassica Challenges and Solutions
There are a few common pests that are attracted to the brassica plant family. Here are a few, and how to deal with them:
Cabbage Worms & Loopers: Use row covers to protect young plants and inspect the underside of leaves regularly.
Aphids: Check under leaves and spray off hard with water.
Bolting: Brassicas can bolt (flower and go to seed) in warm temperatures, especially if stressed. Growing in cooler seasons is suggested for the best results. Tip: Let them flower for the pollinators!
Crop Rotation: Avoid planting brassicas in the same bed year-after-year to prevent soil-borne diseases.
Benefits of Growing Brassicas in Your Garden
Nutrient Powerhouses: Brassicas are rich in tons of vitamins including A, C, and K, as well as folate, calcium, and fibre. They’re known for their cancer-fighting compounds like glucosinolates and antioxidants that support detoxification and immune health. In other words, you can’t go wrong adding brassicas to your diet!
Great for Cold Weather Growing: If you’re like me, and live in climates that get cool weather in the spring and fall, brassicas will thrive in your garden during these season. Unlike tomatoes or peppers, brassicas love cool temperatures, and can even tolerate light frosts.
Companion Planting Allies: One of my favourite ways to combat pests in the garden is through companion planting. Brassicas can help repel pests when grown alongside onions, dill, chamomile, or nasturtiums. However, they don’t play well with other brassicas! Space them out to avoid competition and shared pest issues or monitor your bed closer.
Diverse Uses in the Kitchen: Whether you’re roasting Brussels sprouts, steaming broccoli, or making buffalo cauliflower wings, brassicas offer endless options for healthy meals & snacks. Broccoli and cauliflower are also delicious raw, served with a dipping sauce as well!
Tips for Success
When planting your brassicas, direct sow radishes and sweet allysum to act as a ground cover and provide more food while they grow taller. Feed your plants monthly with organic fish fertilizer, or compost to keep plants thriving. Lastly, harvesting your leafy brassicas (ex: collard greens) regularly for continued growth. Simply pick the outer leaves as needed. For head-forming types like cabbage and broccoli, wait until the head is full and firm before cutting and harvesting.
Growing brassicas is a rewarding endeavour for gardeners at any level, and a great crop to grow in the cooler months. With a some preparation, you’ll enjoy bountiful harvests of crisp, nutritious veggies throughout the upcoming fall season. Just keep in mind, they take up space so plan wisely! Ready to plant? Start with a few favourites like purple cauliflower or broccoli, and you’ll be hooked on brassicas in no time!
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