Fothergill's Growing Guide: Brussels Sprouts

Average time to harvest

28-32 weeks

Sowing depth

1.5cm

Soil type

Well cultivated, well drained fertile soil

Love them or hate them, the Brussels sprout is a Christmas dinner staple. They have a reputation for being bitter but grow them yourself and you’ll be rewarded with sweet, slightly nutty flavours instead.

Want to know how to grow Brussels sprouts? Our growing guide will tell you everything you need to know.

Did you know?

Its botanical name is Brassica oleracea Gemmifera.

First cultivated in ancient Rome, Brussels sprouts are a member of the brassica family. They get their name from the capital of Belgium, where they were a popular vegetable during the 16th century.

You know when you’ve overcooked sprouts, as they give off a distinct sulphur smell.

A cup of cooked sprouts contains the entire daily recommended amount of vitamin C. They are also a good source of vitamin A, potassium, and fibre.

There are different varieties of sprouts including dwarf, large, purple, and speckled varieties.

Growing at a glance

Brussels sprouts are a slow growing vegetable. They like to grow in full sun, but will happily tolerate the frost. In fact, cold weather improves their taste. They’re a greedy plant, so ensure plenty of organic matter is incorporated in their growing area.

As they can grow quite big, it’s important to give them plenty of growing space.

Most Brussels sprouts varieties grow tall and will need staking. Plant them in firmly to help prevent wind rock.

As the plants mature, give them a high nitrogen feed. Weed regularly and ensure the soil is always kept moist, especially during dry spells.

Remove yellowing leaves to help prevent pests and diseases and improve ventilation.

Brussels sprouts form from the bottom of the plant upwards, and are ready to harvest 28-32 weeks from when they were sown.

Always rotate brassica crops, if possible grow them in a different location each year, to reduce the chance of soil borne diseases building up.

Sowing seed

Brussels sprouts can be sown indoors from February onwards. Use standard or modular seed tray and fill with a seed compost mix. Tamp the compost down to create a firm surface, then sow thinly. For modular trays create a 0.5cm hole in the centre. Place two seeds in the hole and cover over with compost. Water gently and place tray in a greenhouse, cold frame or on a windowsill to germinate.

Germination should occur within 14-21 days, or more quickly if you’re using a heat mat, heated greenhouse or heated propagator. Once germinated, give them plenty of light so they don’t become leggy.

Direct sowing into the final growing area, or into a separate seed bed, can be done from late March to April, when the soil is warmer and more workable.

Prepare the open growing area by adding plenty of organic matter and working it into the soil. Firm the soil down with the back of a rake, or use your heels to walk over the growing area, and then create a fine, level tilth. Water the area before sowing to avoid dispersing the seed.

For seed beds, create drills 1cm deep and 15cm apart. Rows should be 60cm apart if you’re sowing directly. Sow seed thinly, then cover over with fine soil. Germination should take between 14-21 days. If sowing early in the growing season, a cloche or horticultural fleece may be needed to protect the sown area.

Pricking out

Once seedlings are firmly established thin to 5cm apart or to one seedling per module. Transplant carefully removed seedlings to other trays. To avoid disturbing the roots, either pinch-out the weaker seedling or cut it away. Keep soil moist.

For plants directly sown into the final growing area, thin seedlings to 60cms apart.

Hints and tips

Harvest from the bottom of the plant, leaving the ones higher up to grow on. Try to pick the ones that are the size of gobstoppers by simply twisting them off.
As these are tall plants, try companion planting alongside beetroot and carrots, or with herbs like rosemary and sage. These will all happily grow in the vacant space below the Brussels sprouts.

Growing on

When indoor seedlings are 10-15cm high, they are ready to be planted out into their final growing positions. Before planting out, let them harden off outside for a week beforehand by bringing your plants outside for a few hours every day so they can acclimatise to outside conditions.

The growing area should be prepared with plenty of organic matter worked into the soil, adding a general-purpose fertiliser, if necessary. Firm the growing area down with the back of a rake. Ideally, the area should be in a warm, sunny, sheltered position. As they get quite tall, plant deeply (up to the first set
of leaves) and firm around the roots. This will help them establish a good root system and prevent wind rock. Plants should be spaced 60cm apart in rows 60cm apart. Water in well. This also applies to plants that were grown and lifted from a seed bed.

Plant maintenance

As the plants mature, they may need staking. Mound-up around the base of the plants to help support them.

These are greedy plants that will need a high nitrogen feed. Water regularly, keeping the soil moist, and keep the area weed free.

Jargon busting

Organic Matter

Broken down matter of plants, leaf mould, manure and compost.

Seed Tray

Used to sow seeds. Once seedlings appear, often pricked out and moved on.

Germination

When a seed begins to grow and its first shoot appears.

Propagator

A covered, typically heated container filled with compost, used for raising seeds.

Tilth Surface

Soil which is fine and crumbly.

Drill
A shallow trench in the ground, for seeds to be sown in.

Pricking Out

Removing seedlings from growing trays and planting them into individual pots to grow on.

Pinching Out

A form of pruning, using forefinger and thumb, to remove a soft stem, encouraging plants to become bushier.

Thinning

Removing seedlings that are growing too close together to allow the remaining crop on successfully.

Common problems

Birds (especially pigeons) and caterpillars will happily eat the leaves of the plants, so place fine netting over the crop at the time of planting. This will also deter the white cabbage butterfly from landing on the plants to lay its eggs during the summer months; an infestation of caterpillars can quickly devastate a crop.

Cabbage root fly larvae feed on brassica roots. When planting into its final growing position, place a brassica collar around its stem, just above the soil. This will help prevent cabbage root fly from laying eggs at the base of the plant, and its hatched larvae from eating and destroying the roots.

Club root is a fungal infection that damages the roots, leaving them swollen, distorted and stunted. The foliage can also discolour. If plants are infected, remove from site and destroy. Wash hands, tools and boots to help prevent the spread of infection. Avoid planting brassicas in areas where club root has occurred. Buy seed varieties that have some degree of club root resistance.