Yummy and delicious broccoli is a very versatile vegetable. The head and stem can be used in heaps of dishes, as well as the mature leaves in salads.

Broccoli is a good source of fibre and protein as well as containing iron, potassium, calcium, numerous vitamins and folic acids.

A member of the brassica family or known as cruciferous vegetables, broccoli can be included in the group with cauliflowers, cabbages, kale, mustard plants and Brussels sprouts.

Follow our seven easy steps to successful broccoli harvest including tips along the way.

How to grow vegetables - Broccoli
Improving soil over winter Seasol Liquid Compost

When to plant and location.

When to plant.

Broccoli is usually planted at the cool times of the year, however with newer varieties it can be planted all year round. Check your local hardware or garden centre for suitable varieties.


  1. Pick a sheltered position in the garden that receives at least 6 hours of sun per day.
  2. Ensure the plants are placed in a position away from high winds as broccoli plants are easily damaged.


Broccoli can be grown in sandy to clay soils, providing it is free-draining. If the soil doesn’t drain easily, create raised soil mounds to plant the seeds or seedlings into.

Follow the steps for successful soil preparation:

  1. Add well-rotted manure and compost like Seasol Super Compost to the soil and dig it in to a depth of 20cm. For a no-dig option use Seasol Liquid Compost.
  2. The pH of the soil should be neutral to slightly acidic around 6-6.5. If it’s too low, add a handful of lime per square metre to the soil.
  3. To boost the soil add Seasol Plant + Soil Booster and a fertiliser rich in potassium such as PowerFeed Controlled Release Tomatoes & Vegetables, so there is a supply of nutrients for plant growth.
  4. Water in well and if possible but not essential, let the soil rest for a week or so.
How to grow vegetables - Broccoli
How to grow vegetables - Broccoli

Step 1 – Sowing seeds.

  • Seeds can be sown in seed trays or directly into the ground. If it’s cool consider placing seed trays in a green house or place indoors on a heating pad.
  • In the soil, sow 2-3 seeds every 15cm in rows 30cm apart and to a depth of about 10cm.
  • In seed trays, fill the trays with Seasol Seed Raising & Cutting Potting Mix and put 2-3 seeds in each single cell. If using a seedling punnet, plant evenly across the punnet every 7-10cm, sowing two rows to a depth of 10cm.
  • Once sown, water the soil with Seasol to help increase seed germination rates. Mix 30mL of Seasol concentrate per 9 litres of water (standard watering can).

Step 2 – Germination

  • Seeds will start to emerge within 5-10 days depending on temperature. The warmer the temperature the quicker the seeds will germinate.
  • When broccoli sprouts, they only have two leaves. These seedlings leaves or cotyledons look like two fat hearts on either side of the stem.
  • Ensure your tiny plants are well watered every day. Do not let the soil or the seed raising mix dry out.
  • Apply Seasol weekly as this will help to stimulate strong root development and promote healthy growth.
How to grow vegetables - Broccoli
How to grow vegetables - Broccoli

Step 3 – Baby broccoli seedlings.

  • About two weeks after the seed leaves have opened up, the true leaves will appear, these look like tiny broccoli leaves.
  • At this stage thin out the weaker seedlings so that they are not competing for nutrients and space.
  • Broccoli seedlings are hungry little critters so give them a good feed with PowerFeed PRO SERIES Plant Food Tomatoes & Vegetables.

Step 4 – Broccoli seedlings ready for transplant.

  • Transplant your own or purchased seedlings when they have two set of leaves or more and are 10cm in height.
  • Plant store-brought seedlings at the depth they were in the punnet. If they look a bit leggy and stretched, plant deeper covering the two bottom leaves.
  • Water your newly transplanted seedlings in with Seasol to get them over transplant shock.
  • Continue to feed your broccoli once a week with a liquid fertiliser such as PowerFeed PRO SERIES for Tomatoes & Vegetables. Mix 20mL of PowerFeed concentrate with 9 litres of water (standard watering can).

Step 5 – Broccoli plant growth.

  • Watch your broccoli plants grow over the following weeks as the stalk develops, the leaves mature and the tiny head starts to appear.
  • Broccoli plants like to stay moist, so check the soil moisture daily and water if necessary. Water the soil around the seedlings in the morning, not the foliage to ensure the plants are dry by nightfall and not susceptible to diseases such as powdery mildew.
  • Apply a layer of mulch such as sugar cane mulch or peas straw to keep the soil warm and the moisture within the soil. The mulch will slowly breakdown overtime, improving the soil.

Step 6 – Broccoli flower growth.

  • The head is the main part of the broccoli plant that we eat. It is actually a tight collection of unopened flower buds.
  • Every 6-8 weeks apply another application of PowerFeed Controlled Release Plant Food Tomatoes & Vegetables to produce a bumper crop.
  • Additionally liquid feed plants with a combination of Seasol and PowerFeed every week. Mix 30mL of Seasol and 50mL of PowerFeed concentrate per 9 litres of water (standard watering can).
  • Check soil moisture daily and water when necessary.

Step 7 – Broccoli harvest.

  • General harvest will start about 10-12 weeks after planting. The head will be around 15-20cm across with tightly closed green buds.
  • Cut the head at an early stage before the flower buds fully develop and open up to give you a nice tight head of broccoli.
  • Once heads have been harvested, store in fridge to ensure the broccoli stays crisp until it’s used.  Enjoy!
  • Small side shoots lower down the main stem will start to produce new heads so keep up the feeding and watering.

Things to watch for…

  • Hungry caterpillars love to chomp on your plant leaves. Keep a close eye on these little critters and pick them off with your hand.
  • Diseases such as various rusts, rot, mildew and leaf-spotting disease can occur. Spray with the appropriate sulphur or copper spray or use an organic spray. Ask your local retailer about appropriate sprays.
  • Environmental stress Inconsistent watering and feeding or high temperatures can cause heads not to form properly and they may bolt, forming tall yellow flowers

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