🥦 Brassicas: The Ultimate Guide to Growing Cabbage, Broccoli, Kale & More

From crunchy cabbages to beautiful purple cauliflower, brassicas are some of the most rewarding vegetables you can grow! 🌱

Brassicas are the unsung heroes of the vegetable garden. They’ve been feeding people for thousands of years, adapting to different climates and finding their way into kitchens around the world.

Whether it’s a freshly harvested head of broccoli, tender young kale leaves or a crunchy cabbage destined for homemade coleslaw, there’s something wonderfully satisfying about growing your own.

And the variety is quite remarkable! From the unusual spirals of Romanesco to the colourful stems of kohlrabi, brassicas come in an incredible range of shapes, sizes, colours and flavours.

🌿 The best part? Many brassicas thrive during the cooler months, keeping the vegetable patch productive when summer crops have finished.

Whether you’re just starting out or you’ve been gardening for years, there’s always another brassica worth trying.

🌍 A Little History: Where Did Brassicas Come From?

Believe it or not, cabbage, broccoli, cauliflower, kale, kohlrabi and Brussels sprouts all developed from the same wild plant!

Their common ancestor, Brassica oleracea, grows naturally along coastal areas of western and southern Europe. Over thousands of years, gardeners and farmers selected plants with particular characteristics, gradually creating the vegetables we recognise today.

Rather than changing everything at once, they saved seed from plants showing the traits they wanted.

🥬 Larger, more tender leaves? Keep those plants for kale.

🥦 Bigger flowering shoots? Select those for broccoli.

🌼 Dense clusters of developing flowers? That’s how cauliflower developed.

🌱 A swollen, crunchy stem? Welcome to kohlrabi!

The changes happened over countless generations through selective breeding.

🌿 One Plant, So Many Vegetables!

Vegetable	What Was Selected Over Time
🥬 Cabbage	Large leaves forming a tightly packed central head
🥦 Broccoli	Enlarged flowering shoots and buds
🤍 Cauliflower	A dense, compact mass of immature flower structures
🌿 Kale	Abundant, tender leaves
🌱 Kohlrabi	A swollen, rounded stem
🥬 Brussels Sprouts	Enlarged buds growing along a tall stem

💡 Did you know? These vegetables are members of the same species, despite looking and tasting remarkably different. It’s one of the most fascinating examples of what traditional plant breeding can achieve.

Not every brassica comes from Brassica oleracea, though. Asian greens, turnips, radishes and other members of the wider mustard family have their own interesting histories.

🥬 Meet the Brassica Family

The brassica family has something for almost every vegetable garden, from quick-growing leafy greens to large, impressive winter crops.

🥦 1. The Classics: Cool-Season Favourites

Broccoli

A reliable favourite that produces delicious, tightly packed green flowering heads.

🌱 Growing season: Usually autumn through spring in warmer Australian regions.
⏳ Harvest: Often around 10–18 weeks from sowing, depending on the variety and conditions.
🥦 Garden tip: Harvest the main head while the buds are still tight. Many varieties produce smaller side shoots afterwards, extending your harvest.

Cauliflower

With its beautiful rounded heads, cauliflower is a wonderful addition to the winter vegetable patch.

🤍 Colours: Traditional white, purple, green and even orange varieties.
☀️ Growing conditions: Prefers cool, steady temperatures and consistent moisture.
🌱 Garden tip: Cauliflower can be a little fussy. Uneven watering, temperature extremes and interrupted growth may affect head development.

Cabbage

From tightly packed green heads to crinkled Savoy leaves and striking red varieties, cabbage is wonderfully versatile.

🥬 Popular varieties: Red Acre, Vertus Savoy and other traditional heirloom favourites.
🍽️ Kitchen uses: Coleslaw, stir-fries, soups, sauerkraut and homemade kimchi.
🌿 Garden tip: Give cabbage enough room to develop its head properly and keep the soil evenly moist to encourage steady growth.

Kale

A fantastic leafy green that keeps producing when harvested regularly.

🌿 Popular varieties: Black Tuscan and Red Russian.
❄️ Growing conditions: Enjoys cooler weather, with many varieties tolerating light frost.
🥗 Garden tip: Pick the lower, outer leaves first and leave the growing tip intact for continued harvesting.

🥢 2. Asian Greens: Quick, Easy & Delicious

If you’re looking for a crop that doesn’t take months to reach the kitchen, Asian greens are well worth growing.

Many are ready to harvest in just a few weeks, making them ideal for smaller gardens, raised beds and containers.

🥬 Bok Choy & Pak Choy

Crisp, juicy stems with tender green leaves. Delicious steamed, stir-fried or added to soups.

🌿 Mizuna

Beautiful feathery leaves with a mild peppery flavour. Excellent for salads, sandwiches and mixed leafy greens.

🥗 Tatsoi

Forms an attractive low-growing rosette of glossy, spoon-shaped leaves. Particularly useful during cooler weather.

🌱 Komatsuna

A versatile Japanese leafy green with a mild mustard flavour. Both the stems and leaves can be eaten.

🥬 Chinese Cabbage

Produces tender leaves with a sweet, mild flavour. Wonderful for stir-fries, salads and fermenting.

💡 Growing tip: Many Asian greens are prone to bolting, particularly when stressed by temperature changes or irregular watering. Sow small batches every couple of weeks during suitable weather for a steady supply.

🌟 3. The Unusual Brassicas Worth Trying

Fancy growing something a little different?

🌀 Romanesco Broccoli

One of the most beautiful vegetables you can grow!

Its lime-green head is made up of extraordinary spiral patterns that repeat themselves in smaller and smaller forms.

Mild, slightly nutty flavour.
Best grown during cool weather.
A real talking point in the vegetable patch!

🌱 Kohlrabi

This unusual-looking vegetable develops a swollen stem just above the soil.

Available in green and purple varieties.
Crunchy, juicy flesh with a mild, sweet brassica flavour.
Delicious raw, roasted or added to stir-fries.

🥬 Brussels Sprouts

These miniature cabbage-like buds grow along a tall central stalk.

Require a long, cool growing season.
Often develop a sweeter flavour after exposure to cold weather.
Harvest the firm sprouts from the lower part of the stem upwards.

💡 Growing tip: Brussels sprouts can be challenging in warmer Australian regions because they need a long growing period with suitable cool conditions. Choose your variety and sowing time carefully. Removing yellowing lower leaves can improve airflow, but stripping healthy leaves won’t necessarily produce bigger sprouts.

🌏 When to Grow Brassicas in Australia

One of the biggest secrets to successful brassica growing is getting the timing right.

Although brassicas are generally considered cool-season vegetables, Australia has an enormous range of climates.

What grows beautifully in a Tasmanian summer may struggle through a Queensland summer!

Australian Climate	General Brassica Growing Guide
☀️ Warm Mediterranean (Perth, Adelaide)	Autumn through spring is generally ideal for most brassicas.
🌤️ Temperate (Melbourne, Sydney)	Many brassicas grow well through autumn, winter and spring, with summer options depending on variety and location.
❄️ Cool Temperate (Tasmania, cooler inland regions)	Spring and summer can be productive, with many hardy varieties growing into autumn and winter.
🌴 Subtropical (Brisbane and surrounding areas)	Autumn and winter are generally the best times for heading brassicas.
🌺 Tropical (Darwin, northern Queensland)	The cooler dry season offers the best opportunity for many brassicas.

These are broad guidelines, so always check the recommended sowing times for your particular variety and location.

🌱 A tip for Western Australian gardeners: In Perth and much of the South West, autumn is a wonderful time to establish broccoli, cabbage, cauliflower and kale as temperatures begin to settle. Fast-growing Asian greens can also be enjoyed through much of the cooler growing season.

🌱 Growing Brassicas: From Seed to Harvest

Brassicas aren’t particularly difficult to grow, but they do appreciate a little preparation.

Get the soil, watering and timing right, and you’ll be well on your way to a productive crop.

🪴 Step 1: Prepare Your Soil

Brassicas are often described as heavy feeders, particularly the larger heading varieties.

They need fertile soil to support strong leafy growth and good head development.

Before planting:

🌿 Add organic matter: Work well-rotted compost or aged manure into the garden bed before planting.
🌱 Check soil pH: Most brassicas prefer soil around pH 6.0–7.5, with conditions closer to neutral often helpful.
💧 Improve drainage: Brassicas enjoy consistent moisture but dislike waterlogged roots.
☀️ Choose a sunny position: Most grow best with at least six hours of direct sunlight daily.

💡 Gardening tip: If your soil is particularly acidic, a soil test can help determine whether lime is needed. Don’t add lime automatically, as excessive amounts can make nutrients less available.

🌱 Step 2: Direct Sowing or Starting in Seed Trays?

This is one of those gardening questions that doesn’t have a single correct answer!

Both methods work, and the best choice depends on your growing conditions, the variety and how much space you have available.

🌿 Method 1: Direct Sowing

Planting seeds straight into the garden bed.

This is particularly useful for quick-growing Asian greens, radishes and turnips, although many other brassicas can also be direct sown.

How to do it:

🌱 Prepare the soil: Loosen the surface and remove weeds, stones and large clumps.
🥬 Sow your seeds: Most brassica seeds are planted around 5–10 mm deep, depending on the variety.
💧 Water gently: Keep the soil evenly moist while the seeds germinate.
🌿 Thin seedlings: Once the first true leaves develop, gradually thin seedlings to their recommended final spacing.
🐛 Protect young plants: Use fine insect netting or suitable covers where pests are a problem.

✅ Advantages

Roots develop without disturbance.
No transplanting required.
Less equipment and preparation.
Ideal for succession sowing and larger growing areas.

⚠️ Things to Consider

Young seedlings are vulnerable to slugs, snails and caterpillars.
Heavy rain can wash away newly planted seeds.
Hot, dry conditions may interrupt germination.
Extra thinning may be needed.

🪴 Method 2: Starting Seeds in Trays

Raising seedlings separately before transplanting them into the garden.

This is a particularly useful method for broccoli, cauliflower, cabbage, kale and Brussels sprouts.

It allows young plants to establish under more controlled conditions before being introduced to the vegetable patch.

How to do it:

🪴 Choose suitable trays: Cell trays or small pots with good drainage are ideal.
🌱 Fill with seed-raising mix: Use a quality, free-draining mix rather than heavy garden soil.
💧 Sow seeds: Plant around 5–10 mm deep and water gently.
☀️ Provide suitable conditions: Keep in a bright, sheltered position. Many brassicas germinate readily at approximately 15–25°C, although preferences vary.
🌿 Harden off seedlings: Gradually introduce them to outdoor conditions over about 7–10 days.
🥬 Transplant: Once seedlings are sturdy and have several true leaves, plant them into prepared garden beds.

✅ Advantages

Better control over watering and growing conditions.
Young seedlings can be protected from pests.
Garden beds can remain productive while new seedlings grow.
Useful for starting the next crop before the current one finishes.

⚠️ Things to Consider

Seedlings need regular attention.
Roots can become pot-bound if left too long.
Transplanting may temporarily slow growth.
Young plants need gradual exposure to outdoor conditions.

🌿 So, Which Method Is Best?

Direct Sowing 🌱	Seed Trays 🪴
Great for quick-growing crops	Ideal for larger heading brassicas
Less equipment required	More control over early growth
No transplant shock	Better protection from pests
Best when garden conditions are suitable	Useful when outdoor conditions are unpredictable

🌼 My suggestion: Try both! Sow a few kale or bok choy seeds directly into the garden and raise another batch in trays. It’s a simple way to discover what works best in your own growing conditions.

🐛 Step 3: Keeping Brassica Pests Under Control

If you’ve ever grown broccoli or cabbage, you’ll know that we’re certainly not the only ones who enjoy eating brassicas!

Their tender leaves can attract an enthusiastic collection of garden visitors.

Fortunately, there are several ways to reduce pest damage without automatically reaching for chemical sprays.

🦋 Cabbage White Butterflies & Caterpillars

Those pretty white butterflies fluttering around the vegetable patch can spell trouble for brassicas!

Their caterpillars chew holes through leaves and can work their way into developing heads.

What helps?

🥬 Cover young plants with fine insect netting.
🐛 Check underneath leaves for eggs and caterpillars.
🌿 Remove caterpillars by hand when practical.
💧 For heavier infestations, a registered Bacillus thuringiensis (Bt) product, such as an appropriate Dipel formulation, may help control young caterpillars when used according to the label.

💡 Important: Secure netting around the edges and keep it clear of the foliage where possible. Butterflies can sometimes lay eggs through mesh that rests directly on the leaves.

🐞 Aphids

These tiny sap-sucking insects often gather on tender new growth and the undersides of leaves.

Try these simple approaches:

Wash small infestations off with a gentle stream of water.
Encourage ladybirds, lacewings and hoverflies.
Remove badly infested leaves where appropriate.
Use a registered insecticidal soap if necessary, following label instructions.

🐌 Slugs & Snails

Young brassica seedlings are particularly tempting to slugs and snails.

Check around seedlings in the evening.
Remove hiding places close to new plantings.
Use collars or suitable physical barriers.
Protect vulnerable seedlings until they become established.

🌿 Common Brassica Diseases

Clubroot

A soil-borne disease that causes swollen, distorted roots, stunted growth and wilting.

Prevention is particularly important because clubroot can remain in contaminated soil for many years.

Rotate brassicas with unrelated crops.
Avoid moving contaminated soil between beds.
Improve drainage.
Maintain an appropriate soil pH.
Remove infected plants and don’t compost diseased roots.

Downy Mildew

Often appears as pale or yellowish patches on leaves, sometimes with greyish fungal growth underneath.

Improve airflow between plants.
Avoid overcrowding.
Water at soil level where possible.
Remove affected foliage.
Use only treatments registered for the crop and disease if chemical control becomes necessary.

🌱 Remember: Healthy, vigorous plants are often better able to cope with minor pest damage. A few holes in a cabbage leaf don’t necessarily mean your entire crop is in trouble!

💧 Step 4: Watering, Mulching & Feeding

Brassicas grow best when they receive a steady supply of moisture and nutrients.

Large leaves lose considerable moisture, particularly during warm or windy weather.

💦 Watering

Water deeply enough to reach the developing roots.
Keep moisture reasonably consistent, especially while heads are forming.
Avoid allowing plants to become severely dry between waterings.
Water near the base rather than regularly wetting the foliage.

🌾 Mulching

A layer of organic mulch helps maintain more even soil moisture, suppress weeds and protect the soil.

Suitable materials include:

Sugarcane mulch
Pea straw
Clean, weed-free straw
Shredded leaves

Keep mulch a little away from the stems to discourage rot and provide some airflow.

🌿 Feeding

Brassicas need adequate nitrogen for healthy leaf growth, but they also require other nutrients for balanced development.

Start with fertile soil enriched with compost and use a suitable balanced fertiliser as needed.

💡 Gardening tip: More fertiliser doesn’t always mean a better crop. Excess nitrogen can encourage lots of leafy growth at the expense of firm, well-developed heads.

🥦 Step 5: Harvesting Your Brassicas

There’s nothing quite like heading into the garden and collecting vegetables you’ve grown yourself!

Knowing when to harvest can make a big difference to both flavour and texture.

🥬 Vegetable	✂️ When & How to Harvest
Broccoli	Cut the main head while the flower buds are still small and tightly closed.
Cauliflower	Harvest when the head is firm, compact and before the curds begin separating.
Cabbage	Cut when the head feels firm and has reached a suitable size for the variety.
Kale	Regularly pick the outer leaves, leaving the central growing point intact.
Bok Choy & Pak Choy	Harvest young leaves as needed or cut the whole plant once it reaches a useful size.
Mizuna	Snip young leaves regularly for salads and stir-fries.
Kohlrabi	Pick while the swollen stem is young and tender, often around 5–8 cm wide depending on the variety.
Brussels Sprouts	Harvest firm sprouts progressively from the lower part of the stalk upwards.
Romanesco	Cut while the head is compact and before the individual buds begin opening.

🌿 Harvesting tip: Try to pick leafy brassicas during the cooler part of the day. They’ll generally stay fresher when they’re not sitting in the hot afternoon sun.

🌼 8 Interesting Things You Might Not Know About Brassicas

1. 🥬 They belong to the mustard family.

Brassicas are members of the Brassicaceae family, which also includes radishes, rocket, mustard and many other edible plants.

2. 🌱 Their seeds can last for years.

Many brassica seeds remain viable for approximately 3–5 years, sometimes longer, when stored in cool, dry and stable conditions.

3. ❄️ A little cold can improve flavour.

Some brassicas, particularly kale and Brussels sprouts, may develop a sweeter flavour after exposure to cool conditions.

4. 🐝 Their flowers are useful to pollinators.

Allowing a few brassica plants to flower can provide nectar and pollen for bees and other beneficial insects.

5. 🥦 They’re packed with nutrients.

Brassicas provide fibre, vitamins and minerals, including vitamin C, vitamin K and folate, although amounts vary between crops.

They also contain glucosinolates, naturally occurring compounds being studied for their potential health benefits. Eating brassicas is part of a healthy, varied diet, but no vegetable can guarantee cancer prevention.

6. 🌿 You can harvest more than one part of some plants.

Broccoli leaves and stems are edible, and young cauliflower leaves can also be cooked and enjoyed.

7. 🌸 White butterfly decoys aren’t a reliable pest solution.

You may have heard that hanging white butterfly-shaped cut-outs around brassicas will keep cabbage white butterflies away.

Although it’s a popular gardening trick, there’s little reliable evidence that it consistently works. Fine insect netting is a much better option.

8. 🌱 Brassicas can cross-pollinate with their relatives.

If you’re saving seed, it’s worth remembering that closely related brassicas may cross with one another.

Cabbage, broccoli, cauliflower, kale, kohlrabi and Brussels sprouts are all forms of Brassica oleracea and can cross-pollinate if they flower together.

That’s particularly important when you’re trying to keep heirloom varieties true to type!

🌱 Why Are My Brassicas Bolting?

Bolting is when a plant switches from producing edible leaves or heads to growing a flowering stem and setting seed.

It’s a natural part of the plant’s life cycle, but it can be frustrating when it happens before you’ve had a chance to harvest!

🌡️ What Causes Bolting?

Different brassicas respond to different triggers, including:

Sudden changes in temperature
Prolonged heat
Exposure to cold followed by warmer weather
Increasing day length
Water stress and interrupted growth

🌿 How Can You Reduce Bolting?

Choose varieties suited to your season and climate.
Sow at the recommended time for your region.
Keep watering consistent.
Avoid leaving seedlings crowded or pot-bound.
Harvest quick-growing leafy greens while they’re tender.
Provide temporary shade during unusually hot weather.

💡 A little reassurance: If a plant bolts, it isn’t necessarily wasted! Young flowers and shoots of many brassicas are edible, and leaving a few plants to bloom can provide food for pollinators.

If you’re growing an open-pollinated heirloom variety, you may even decide to let suitable plants produce seed for a future crop.

🌻 Companion Planting with Brassicas

Brassicas can fit beautifully into a mixed vegetable garden, particularly when combined with flowering herbs and smaller crops.

Some commonly suggested companions include:

🌼 Sweet Alyssum: Its tiny flowers attract hoverflies and other beneficial insects.
🌿 Dill and Coriander: Allow a few plants to flower to provide food for beneficial insects.
🥬 Lettuce: Can make use of spaces between young brassicas before they reach full size.
🌸 Nasturtiums: Attract pollinators and may draw some pests away from nearby crops.
🌱 Peas and Beans: Useful in crop rotations because legumes can contribute nitrogen to the soil when their residues decompose.

Companion planting can help create a more diverse garden, but it won’t automatically prevent caterpillars or disease.

🌿 My suggestion: Combine companion planting with good spacing, crop rotation, healthy soil and insect netting for a more reliable approach.

💚 Why Brassicas Deserve a Place in Every Vegetable Garden

Brassicas offer something for almost every gardener.

They’re wonderfully varied, full of flavour and particularly useful for keeping the vegetable patch productive during the cooler months.

From quick-growing mizuna that can be ready in just a few weeks to the long, patient growing season of Brussels sprouts, there’s a brassica to suit different spaces, climates and levels of gardening experience.

And if you enjoy growing heirloom vegetables, brassicas have an especially interesting story. Every traditional cabbage, kale and broccoli variety represents generations of gardeners selecting, saving and sharing seeds.

🌱 Start with something easy, like kale, bok choy or a reliable cabbage variety, then experiment with a few of the more unusual members of the family.

You might discover that the humble brassica becomes one of your favourite things to grow!

🌱 Explore the Brassica Family at Seed Station

Feeling inspired to grow a few brassicas in your vegetable patch? 🥦

At Seed Station, you’ll find a lovely selection of heirloom and traditional brassica varieties, from everyday favourites to unusual vegetables worth trying.

Click on any variety below to visit its individual seed page, where you’ll find growing information, sowing times and more.

🥦 Broccoli

🥬 Cabbage

🤍 Cauliflower

🌿 Kale

🥬 Brussels Sprouts

🥢 Asian Greens

🌱 Mizuna

🌶️ Mustard Greens

💜 Kohlrabi

Kohl Rabi Purple Vienna

🌼 Other Members of the Brassica Family

The brassica family also includes a few vegetables you might not immediately associate with cabbages and broccoli!

Turnips

Radishes

🌼 Why not try something new this season? Whether it’s a colourful purple cauliflower, a beautiful Romanesco or a quick-growing Asian green, there’s always another brassica waiting for a place in your garden.

Happy growing! 🌱