How to grow purple sprouting broccoli

Enjoy regular harvests of tasty purple sprouting broccoli spears
Image: Broccoli 'Summer Purple' (Purple Sprouting) from Thompson & Morgan

Purple sprouting broccoli is a delicious superfood packed with iron, folic acid, calcium, fibre and vitamins A and C. Despite being expensive to buy in the supermarket, purple sprouting broccoli is an easy vegetable to grow. And, if you choose the right varieties, it will provide you with a tasty cut-and-come-again harvest almost all year round. Here’s everything you need to know about growing purple sprouting broccoli.

In the meantime, browse our full range of brassica and leafy green seeds for more inspiration. 

Why you should grow your own purple sprouting broccoli

Purple sprouting broccoli adds something special to your dishes
Image: Broccoli 'Purplelicious' from Thompson & Morgan

Already a luxury item for many budget-conscious families, growing your own purple sprouting broccoli not only saves money, but freshly picked stems have a higher vitamin content and a superior flavour. 

However, purple sprouting broccoli plants grow quite large and take up a lot of space. They usually stay in the ground from early summer through to the following spring, so you will need to dedicate a significant area to their cultivation. On the plus side, they are very hardy and reliable, and just a few plants guarantee a steady supply of fresh veg at a time in the winter when little else is available. About six plants should easily feed a family of four. 

How to sow purple sprouting broccoli seeds

Start your broccoli from seed for a cost-effective way to grow this luxury superfood
Image: Broccoli 'Purple Rain' F1 Hybrid (Purple Sprouting) from Thompson & Morgan

Purple sprouting broccoli is traditionally a slow-growing winter crop, but new, fast-maturing varieties can be harvested from late summer. It’s important to check your seed packet for specific instructions.

• Traditional winter-cropping varieties should be sown in March (to harvest in November and December) and then sown again between April and June (for crops the following January to May). 
• Sow your seeds 13mm deep in trays or small pots on a bright windowsill. 
• When the seedlings are about 8-10cm tall and have four or five leaves, harden them off ready to transplant into their final outdoor positions. 

How to plant out purple sprouting broccoli

Stake your broccoli plants to prevent wind-rock
Image: Shutterstock

Purple sprouting broccoli usually reaches a height of about 90cm tall and 60cm wide, so each plant needs plenty of room to grow. 

• Space your plugs or young plants 60cm apart in every direction.
• Plant them slightly deeper than they were growing in their pots. They don’t like loose soil, so tread it down with your foot before you start, and firm the plants in well.
• They like a sheltered position in full sun (at least 6 hours a day) where they will be safe from wind-rock. Stake your plants if necessary.
• Slightly alkaline soil produces better results. If your soil is acidic, simply add some lime. 
• Keep the soil moist as your plants grow.
• Like all brassicas, you’ll need to protect your plants from insects and birds with mesh. Some gardeners opt for a dedicated brassica cage. 
• Use a liquid feed if the purple flower buds are slow to form. 

How and when to harvest purple sprouting broccoli

Make sure you cut the entire length of your PSB when harvesting
Image: Broccoli 'Purplelicious' from Thompson & Morgan

As soon as you see the purple florets starting to form, pinch out the main head. The leaves, stem and flower head of this main shoot are all edible, making your first harvest a special treat! In the next few days you’ll see larger side shoots starting to form, and these can be picked as and when you need them. 

• Cut the entire shoot, 5-10cm long, with a sharp knife. The sweetness is in the edible stem.
• Harvest the shoots regularly to keep your plants cropping – the more you cut the more you get. 
• Don’t let any of the flowers actually open or the plants will run to seed and production will cease. 

Best purple sprouting broccoli varieties to try

For something different, try growing this ‘white’ version of purple sprouting broccoli
Image: Broccoli 'Burbank' F1 Hybrid (White Sprouting) from Thompson & Morgan

T&M’s horticultural team recommends growing several different varieties to extend the cropping season. Here are some of their favourites to try: 

• Broccoli 'Purple Rain' F1 Hybrid – this British bred variety crops continuously, producing chunky stems that are perfect for steaming and store well in the fridge. 
• Broccoli 'Burbank' F1 Hybrid (White Sprouting) – The first British-bred, white sprouting broccoli, these strong, vigorous plants produce a high yield of large, tasty spears over several weeks from February. 
• Broccoli Sprouting 'Summer Purple' – is specially bred for summer cropping, with good heat tolerance and no need for winter chilling. It produces high yields from July to November if sown at regular intervals. 

Growing your own purple sprouting broccoli requires time and space, but the rewards include a reliable harvest of nutrient-rich stems that you can pick as and when you need them. For more information and advice on growing brassicas, visit our helpful hub page.