How To Grow Broccoli
Broccoli (or Calabrese) is easy to grow and quick to harvest, producing multiple green or purple sprouts of one of the healthiest brassicas you can eat. Read our handy guide and we’ll show you how to grow it.
Most common Broccoli plant questions
When can I plant Broccoli?
You will be ready to plant your broccoli plants outdoors from April to July.
Plant out after the last frost has passed.
What kind of soil does Broccoli need?
It is best to grow Broccoli in a mix of three-parts quality compost and one part topsoil.
If you can get it, choose compost specifically for growing vegetables.
If possible, lay in some well-rotted manure the previous Autumn to give the soil more nutrients and improve its texture.
How much sun does Broccoli need?
Plant Broccoli in full sun.
Pick a spot where the plants will receive 6 to 8 hours of full sun everyday.
How to plant Broccoli plants
Plant Broccoli in rows 30cm apart with 45cm between the rows.
If you are growing the Broccoli in containers, then you can grow one plant in a 7L pot, or up to three plants in a 15L pot spaced equally apart.
Dig a hole slightly larger than the roots, pop the the plant in, and then fill in with the compost mix. Gently firm in with the tips of your fingers so the plant is secure in the ground. Give the plant a watering to help the soil settle around the roots.
The more space between Broccoli plants, the bigger the heads will grow.
If you are growing in a pot always be sure that the pot has drainage holes at the bottom to allow water to drain away and not rot the roots.
How much water does Broccoli need?
Broccoli needs to be watered regularly and the ground kept consistently moist.
Usually until June the rain will take care of this, but then check up on the plants by simply touching the soil. If it feels dry down an inch into the ground, then give the plant a water.
When the weather is really hot, this may require you to water the plant every day. However, it is important not to overwater your Broccoli as this can cause disease and rot below the soil.
How to feed Broccoli plants
Feed Broccoli plants with a balanced organic fertiliser.
This could be worm castings or chicken manure pellets - sprinkle them around your plants just after planting to give a short boost of nutrients to the plants for a bigger crop.
How to harvest Broccoli
Broccoli takes around 8-12 weeks to harvest after transplanting outside.
You should see a thick broccoli head forming in between the leaves. Cut this off with a sharp knife at its base where it meets the stem.
Heads of Broccoli are actually flower buds which haven’t bloomed yet. If left alone, these buds will form yellow flowers. You want to harvest Broccoli before this happens and you have to be careful because if there is consistently hot weather the Broccoli might ‘bolt’ and flower earlier than expected. Do not worry however if your Broccoli has bolted, the yellow flowers are edible and can be used in salads.
Common Broccoli plant problems
The most common Broccoli pests are caterpillars, cabbage root fly, slugs and birds.
It is recommended that you cover your Broccoli (and all brassicas) with a garden fleece to prevent them being eaten by pests. A fleece will help protect your broccoli from most of these pests.
Also be sure to keep the surrounding ground free of weeds to improve the plant’s health. Read below for specific information on these individual issues.
Cabbage Root Fly
Cabbage Root Flies look like small, grey house flies.
They lay their eggs near the base of most brassica plants. The resulting maggots then burrow their way into the root system of the plant, feeding on it and causing the plants to wilt, become yellow and possibly die.
A horticultural fleece to prevent the flies from landing near the plant is the best form of protection against this pest. To add extra protection against cabbage root fly you can also use a brassica collar which prevents the flies from laying their eggs at the base of the plant.
You can also plant Sage near your plants will help deter the Cabbage Root Fly and prevent them from laying eggs near your plants.
Check under the leaves of the young plants for eggs.
Wipe them off if you see any. More than likely this will be the eggs of the White Butterfly, which will hatch into caterpillars and really damage the plant. If caterpillars have hatched, pick them off ASAP.
To combat slugs, try watering in the morning which will give the water time to evaporate off the surface during the day before they come out at night.
You should also keep your garden area clean and clear the surrounding area of any weeds and debris such as logs, tiles, or old plant pots where the slugs may be hiding under during the day.
A good way to prevent slug damage is to create a barrier around your plants. You can do this either with copper wire, which will react with the slug’s mucous, or crushed egg-shells which will cause little cuts which will then dry the slugs out. For you barrier to be effective, however, you must ensure there is nothing touch your plants that can form abridge for the slugs. If a leaf is touch a wall, for example, slugs could simply climb up the wall to reach the plant.
Another good organic method to get rid of slugs is using Nematodes. Nematodes are microscopic worms that essentially find slugs underground and cause them to die. They are completely harmless to other wildlife or your vegetables (or you when you eat your vegetables) and so are a great organic solution to slug damage. Make sure you read and follow the instructions on the packaging carefully.
Broccoli can suffer from Club Root, which affects most brassicas - you may see the leaves wilt and turn purple.
Below ground the roots will have become swollen and bulbous. Club Root is caused by an infection so if it occurs you should not plant brassicas there again for 4 years. Try to combat it by ensuring your soil drains well and also making it more alkaline by liming it.