Crop rotation, what to grow?

[hedgehogsdontbite]

We have 4 raised boxes which I use for growing veg. I rotate what I grow in them each year. I have a potato box, a root veg box and a peas and beans box. My issue is with the fourth box. I believe it shpuld be brassicas but I just can't get them to grow anything worthwhile. I've tried turnips, cauliflower, broccoli and kale but none of it grows well enough to be worth the effort.

Any ideas of what else I could try? (I'm in southern Sweden so climate is like north Scotland if that makes a difference)

[shovetheholly]

If you're doing well with the other crops, the issue may be the soil - are you adding lime and using fairly sparing amounts of manure?

Also, buying plants rather than trying to get seeds to germinate can help!

Chard might be worth a try, and kohl rabi?

[hedgehogsdontbite]

We only add manure the year a box is used for potatoes. The following year lime is added and peas are grown. The 3rd year nothing is added and is supposed to be the brassicas. The plants grow, they just don't have anything worth harvesting.

[shovetheholly]

Hmmmm, you sound like you know what you're doing! I wonder what the problem could be? My (very amateur and possibly wrong) understanding was that brassicas liked cool climates with plenty of rain, so I am puzzled. Can you describe what happens to them in a bit more detail? For instance, if you plant kale, do you just get only a small yield, or what?

A couple of other ideas:

Are you protecting them from cabbage root fly? This could be a reason for a completely failed crop, though by the sounds of things your plants are growing, so this may not be the issue?

Are you waiting long enough? I have been a bit surprised, here in northern England, by how much longer brassicas seem to take than books say (though it has been a cold winter and spring here). I put in some Caulis in October, and they have grown but didn't curd when they were supposed to in March. I left them, and they are just starting to produce lovely white curds! But it feels like it's taken aaaages.

I would give cabbages a go, because at least if they don't turn into proper heads, you will get spring greens, which is something. What about kohl rabi too? That's supposed to be really quick.

[hedgehogsdontbite]

It possibly is that they don't get long enough. We planted everything over the last week and by the time the weather starts to get cold again (mid August) the brassicas are just beginning to show, but they can't be left any longer. The Kale just looked withered and pointless. The caulis had what looked like the beginnings of the white bit. The broccoli grew but everything edible was enough for just one meal, so a bit pointless.

I'm very much a beginner but have just been lucky with the other stuff.

[shovetheholly]

OK, so that might be part of the issue with your longer-season crops like caulis and broccoli. One thing you could try would be to extend the season at either end by sowing indoors and then growing on under cover - in a cold frame, and then under large cloches, which you then remove about now. You could also cover with fleece in the early autumn to extend that end of the year too. However, I would be a bit careful with this because I've had a quick google and brassicas really do like the cool.

Something else is going on I think. I am bemused that turnips aren't growing for instance. A variety like 'Market Express' is very quick, and if you planted now should be ready in 4-6 weeks. Even regular varieties should be ready by the end of the summer.

Having thought about it, I wonder if your problem is lack of nitrogen. This would explain the plants not being able to get on and grow. Adding fish, blood and bone may help. However - here's the kicker - you can't add fertiliser in the same 3-4 months that you've limed, because they react together, cancel each other out and produce ammonia. So next year (or this year on a non-limed bed), try using just fertiliser and see if that helps.

Clubroot might be another problem - have you had a look at the roots? www.allotment-garden.org/vegetable/Club-Root-Plasmodiophora-brassicae.php

[Takver]

In your situation, I'd fill my fourth box with salads - providing you like them, of course!

Also, how big are your boxes? You may find you actually need to add muck for the brassicas too - I'd tend to muck the spuds, lime the peas/beans, muck the brassicas.

[AlternativeTentacles]

Kohl rabi, radishes for the seed pods, and lettuces and the brassica salads like pak choi, mizuna etc. sow little amd often for a lomger harvest. And dont forget spinach!