Grow

By David Marks
This page is about when, how and where to sow Brussels Sprouts. More so than many vegetables, you need to get the timing and conditions correct for a good crop.Those with clay soils will do better at growing Brussels Sprouts than for many other vegetables. They need a firmish, slightly alkaline  soil with a bit of body to support the long stems. Sandy soil will need lots of improvement.

QUICK CALENDAR FOR GROWING BRUSSELS SPROUTS

Buy or borrow a soil testing kit (optional) the third week of January

Add lime if necessary to reduce soil acidity the third week of January

Sow seed of early varieties the second week of March

Thin seedlings as they appear the last week of March

Sow seed of mid to late varieties the first week of April

Transplant seedlings when 13cm tall - the last week of May

Begin to harvest - the third week of November

BEST SOIL AND POSITION FOR BRUSSELS SPROUTS

Soil and position are the key to growing Brussels Sprouts well and it's all down to the plants being unusually tall and liable to wind damage. They prefer a firm soil with some body to it but also free-draining.

An average clay soil which drains well is perfect for your Brussels Sprouts. Lighter soils can be improved by the addition of organic matter and a technique we describe in the care section of this article.

Any digging of the soil for Brussels Sprouts is best done in the autumn prior to sowing seed / transplanting. This will allow the soil plenty of time to settle down and provide the firm soil which this tall vegetable needs. If you plan to add well-rotted manure, do this now but not just before transplanting.

SOIL ACIDITY / pH LEVELS
As with all brassicas, Brussels Sprouts are liable to a range of diseases if the soil is too acidic, club root in particular. The only way you will know if your soil is acidic or not is to buy a soil testing kit.

These kits aren't expensive, they are simple to use and can save a lot of the heartache if things go wrong. We took a quick look around the internet and found that there are perfectly good soil testing kits available for around £10 including postage - they will all test the soil pH many times over.

If you find out that your soil is too acidic then give thanks that you found out before attempting to grow Brussels Sprouts on it! A soil pH much below 6.5 and you will need to apply some very cheap lime to your soil before planting any brassicas. Head off down to your garden centre and they will be sure to have some in stock. Dig it in following the dosage instructions on the pack.

ESSENTAL CROP ROTATON
Another essential with Brussels Sprouts and all brassicas is that they should not be planted on the site of a brassica crop in the previous year or two. See our crop rotation page for more details on how to rotate crop plantings over a four year period.

SUN, WIND AND SOIL NUTRIENTS
Sprouts grow well in both full sun and partial shade but remember that they are tall pants and will cast quite a shadow from July onwards. Do your best to site them in a position protected from wind. Their foliage is minimal so planting other quicker crops in between them works very well, try lettuce, radish, swede or rocket as companion vegetables. 

Prior to planting Brussels Sprouts in their permanent positions they will appreciate a good handful of fish, blood and bone fertiliser every square metre (yard) a couple of weeks before transplanting. Lightly rake the soil (don't dig it at this stage) to mix the fertiliser in well.

WHEN AND HOW TO SOW BRUSSELS SPROUTS SEEDS

Whatever method you use initially to grow your Brussels Sprouts it's useful to note that they do better if they are transplanted at a young age. This seems to encourage fibrous root growth which in turn anchors the plant more securely to the soil.

The method below has the seed sown in a seed bed and then transplanted to their final position but they do equally well with the first stage being in a seed tray or pots. If sowing in a seed tray or pots do not any additional feed to the seed compost, it will already have sufficient nutrients in it.

Brussels Sprouts seed is normally sold as early (e.g. Crispus, Cromwell, Maximus, Red Ball) or mid / late (e.g. Bedford, Millennium, Montgomery, Titus). Sowing some early and some late varieties and you have the real possibility of being able to crop from as early as mid September to very early March. Both early and mid / late seed is sown in exactly the same way, only the timing differs.

Prior to sowing seed, the soil in the seed bed should be prepared as described below. Use a forked trowel to create a fine tilth on the surface of the soil - do not dig at this stage though because this would loosen the soil too much. Work in a handful of blood fish and bone per metre.

Sow early varieties of Brussels Sprouts in the second week of March and mid to late varieties in the first week of April.

Draw a line in the soil about 1.5cm / ½in deep and thinly sow the seeds. Cover with a thin layer of soil and gently firm down, water the seeds in well with a fine-rose watering can.

If you have more than one row space them 29cm / 8in apart. Unused seeds for Brussels Sprouts will keep well in a dry dark place for three years. The seedlings of Brussels Sprouts will appear after approximately ten days and as soon as they are large enough to handle
thin them out
to 10cm / 4in apart.

Cabbage Root Fly can be a major problem in many areas and a key preventative measure is to lay small discs of felt, cardboard or similar material on the soil around the stem of the plant.

This will stop the flies laying eggs in
the soil near the stem of the plants. This can be left until the transplanting stage but the first generation eggs of this pest will probably already have been laid at the base of the plant at that stage.

Click here for our next page on Brussels Sprouts showing how and when to transplant them, ongoing care and how to harvest them.