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Australian Grow Guide: Broccoli

Broccoli is not only a winter staple for many people but it can actually be grown for most of the year in almost the whole of Australia.

Growing Broccoli might sound hard – but it’s no harder than growing your average, everyday garden vegetable. 

You can even grow broccoli all year round provided the temperature is right.

Here’s what you need to know:

Appearance and Characteristics

broccoli growing | Fruit & Vegetables

Broccoli is an annual plant in the Brassicaceae family, which also includes cabbage, cauliflower and kale. It has edible flower heads and thick, tender stalks which may be eaten raw or cooked. 

The flower heads are usually green, but some varieties do have purple and even red blooms.

Broccoli has high levels of vitamin C, K and A. Broccoli also contains fibre and calcium, yet it has zero cholesterol.

Of the many varieties of broccoli, we’re most familiar with Calabrese broccoli. It’s the popular variety in Australia, and it is often the first broccoli you’ll see at the grocery store.

When to plant Broccoli in Australia

Traditionally a cool season crop, Broccoli can now be grown year-round in Australia, thanks to a range of different varieties of the plant.

However, Autumn is generally considered the best time to plant broccoli, for harvesting in Winter or Spring.

In temperate climates, broccoli can be sowed right through winter.

Broccoli is often planted into seed trays in Summer for planting out in early Autumn.

How to grow Broccoli from seeds

Broccoli is a cool-season vegetable that is easy to grow. It’s best to start broccoli seeds indoors, and then transplant the seedlings when they’re about eight weeks old.

Broccoli needs a lot of space—about 40 cm between plants, so it’s best to grow them in large planter boxes or better yet in an area where you have plenty of space in your garden.

You can plant broccoli seeds any time of year, depending on the variety and your local conditions. The earliest harvest will come from planting early in Spring.

Broccoli grows well in a pH range from 6 to 7 and it’s important to keep soil temperature between 18°C and 24°C for optimal growth.

Grow Guide: Broccoli

vegetables broccoli | Fruit & Vegetables
Family: Brassicaceae
Genus: Brassica
Plant type: Annual
Height: 45–60cm
Climate: Suitable for most climates
How to plant broccoli
Soil: Rich soil with good drainage
Soil pH range: 6 to 7
Soil temperature: 18°C to 24°C
Spacing needs: 40cm
Seed depth: 1cm
Germination days: 7 to 10 days
When to sow: Autumn
Caring for broccoli
Sun: Full sun
Water: Every 3 days
Feeding: Apply a low nitrogen fertiliser after planting, then apply a balanced fertiliser fortnightly
Harvesting broccoli
Time to harvest: 8 to 20 weeks
When to harvest: When the central head is deep green and fully developed with small, tightly packed buds

How long does Broccoli take to grow?

Broccoli grown from seed takes 8 to 20 weeks to be mature enough to harvest. 

The time it takes for broccoli to grow from seed depends on the variety, the growing conditions, and how quickly the seeds germinate. For example, some varieties can take only 5 days for germination, while others take up to 10 days or more.

When to harvest Broccoli

Broccoli will be ready for harvest around 8 to 20 weeks months after being sowed.

Broccoli should be harvested as soon as the first heads are ready, before they start to flower.

In doing so, you’ll encourage the development of new growth, so you can harvest your plants for months to come.

Broccoli heads that are ready for harvest will be firm and compact. The heads should be from 10 to 18cm across, depending on the variety.

You want to harvest them before the head starts to open up and flower as this impacts the flavour.

In terms of colour, harvest your broccoli when the heads are a consistent dark green. The florets starting to turn yellow is an indication that they are about to open up in preparation for flowering.

How to grow Broccoli in a pot

The first step is to pick out the right pot. The size of the pot depends on how much space you have available and how many heads of broccoli you want to grow. 

Plant seeds 1cm deep and keep them moist until they germinate (about 7-10 days). Once they have sprouted, thin them out so that only one plant remains per 40cm.

You can grow two heads in some pots but it is best to give each head plenty of room so that it does not compete for nutrients with other plants in the same container.

Broccoli needs plenty of water so make sure that your soil is well drained. If necessary, add organic matter such as compost to improve drainage before planting your seeds.

Because broccoli is a cool season crop, you’ll want to make sure that your pots never get too hot (black containers can be problematic).

Broccoli grows best in full sun but will tolerate partial shade as long as temperatures remain warm enough during the day (i.e., above 10 degrees Celsius).

Broccoli Pests and Diseases

In order to properly grow broccoli in Australia, you’ll need to keep an eye out for any signs of attack by pests or disease.

Pests that can impact broccoli include:

  • Aphids
  • Caterpillars
  • Mites
  • Whitefly
  • Cabbage root fly
  • Cabbage aphid
  • Cabbage white butterfly

Diseases that can impact broccoli include:

  • Bacterial soft rot
  • Blackleg
  • Clubroot
  • Damping off
  • Downy mildew
  • Leaf spot/target spot
  • Powdery mildew 
  • White blister
  • White leafspot
  • White mould
  • Wirestem

Broccoli Companion plants

Broccoli companion plants help improve the soil and protect against pests. 

These include:

  • Beetroot
  • Celery
  • Chamomile
  • Lettuce
  • Potatoes
  • Rhubarb
  • Rosemary
  • Shallots

Broccoli FAQ

How much broccoli do you get from one plant?

Most varieties of broccoli produce one large head per plant, but broccolini, or sprouting broccoli, produces a number of small florets.

Photo of author

Steve Kropp

Based in Melbourne, Steve's passion is vegetable gardening, and he’s been writing about it for almost 5 years. He also loves all things DIY and is always looking for a new project. When not working on his own garden projects or blogging, Steve enjoys spending time with his family, cooking meals with produce harvested from his garden, and coaching his son’s footy team.

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