Top Of The Crops - Beetroot

Growing Beetroot in a Polytunnel

Beetroot is a crop that is ideally suited to polytunnel growing. It is a plant that does not take up a huge amount of space and it has a long growing season, especially when it can be grown undercover. Practice successional planting and preserving techniques and you can be enjoying beetroot for much of the year. This is a far more versatile vegetable than you might imagine and can be used in a number of different ways. Home grown beetroot is delicious and bares little resemblance to the shop-bought stuff, doused in vinegar.

Beetroots will grow well in a polytunnel and will do well when planted alongside onions and brassicas. There is evidence that suggests that runner or French beans and beetroot may stunt each others growth and should be kept apart, which is worth bearing in mind when planning your polytunnel layout. Two secrets to growing:
1. Beetroot has a natural inhibitor to germination. Soak seed in tepid water for half an hour before sowing.
2. Avoid growth checks and don’t allow globes to get too large.

Seed Sowing

Beetroot is not particularly fussy when it comes to growing conditions but it does require a fertile growing medium. Add compost to your soil before sowing the seeds, which you can do any time between March and July. In order to improve the rate of germination, you can soak seeds for half an hour in tepid water prior to sowing to remove the natural germination inhibitor that is present on the seeds. Sow thinly and to a depth of around 1-2cm.

It is important to water consistently and it is a good idea to mulch with a good organic fertiliser. One that is high in nitrogen will boost foliage growth but take care not to provide too much nitrogen or the plants can create leafy growth at the expense of the root formation.


Mature beetroot can be harvested between June and October. As your beetroot grow you will have to thin them to leave the remaining plants room to grow to maturity. The good news is that you can eat the beetroot that you thin. These baby beetroot are fiddly to deal with but boil them, mud and all, in a saucepan of water and they will pop right out of their skins and be perfect in a spring or summer salad.

Beetroot are at their tastiest when they are around the size of a golf ball or a little larger. You can wait until they reach tennis ball size but should not wait too long or they can become tasteless and woody. Thin and eat alternate beetroot as they grow and do not throw the leaves away! Beetroot leaves are delicious to eat and are a secondary crop that should not be wasted.

To store beetroot, twist off leaves (do not cut them off) and place to roots between layers of dry potting medium in a box. They should also keep in the ground of a polytunnel throughout the winter as long as they are not subjected to a hard frost, which can damage the roots. Protect with horticultural fleece and lift the roots as needed over the winter months.


Early crop to be ready late May sow both resistant varieties in March under cover.
Could sow three seeds to a pot to plant out later.

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