Sallygarden Smallholding - The Forum For Sustainable Living

I wondered the reason why brassicas are grown outside on the plot rather than in a polytunnel. Is just a question of space or would they bolt in the warmth of the tunnel?

I grew kale in the tunnel over winter and it was superb. It has only just gone to flower now, but thats no earlier than the kale I grew outside. I wondering if I'll get problems if I grow some leeks in the tunnel, or even swedes, kohl rabi, turnips or parsnips.

I should think they'd all be fine, although things susceptible to fungus infection are probably best outside since humidity can be high in there in autumn. The tunnel is the most productive part of your garden, so use what space you have wisely.

Brassicas are notoriously space-hungry, but do frighteningly well in the sheltered conditions of the tunnel. I'm on light, sandy soil and although I'm working on improving it, caulis just won't grow outside (they're the fussiest of the brassicas). Inside, however, they go nuts - last spring I harvested one head that was just over a kilo and fed the family for three days!

One word of warning: butterflies will seek your tunnel out, and once inside become trapped and lay eggs over every brassica you've got. This can make your life a misery throughout the summer unless you have your brassicas under fleece the whole time, or invest in netting for the doorways; this can be done by making new mesh doors and keeping them closed, or by rigging makeshift mesh curtains.

Good luck!