I think that cabbages are one of the most difficult vegetables to grow organically. There are so many creatures and diseases that want a piece of the action before you get a look in. Last year I discovered that the soil here is riddled with clubroot, a fungal soil-bourne disease that causes the roots to become swollen and that stunts the plants. It affected the cabbages badly but the wallflowers and swedes (turnips) grew OK. The plot was one large bed but I had divided it into many raised beds so it was likely, but not inevitable, that all the beds were affected. I wanted to test how good the new clubroot-resistant varieties are so I planted ‘Kilaxy’ (available from most UK and Irish seed suppliers) in two beds where the plants had been affected last year. I raised the plants in cell trays and planted them out in May.
The plants have grown quite well though they are a little smaller than I expected but that could be due to close spacing. There is some caterpillar damage but not as much as on some others and that could have been overcome if I was more diligent in picking off the pests. ‘Kilaxy’ is a late summer/autumn cabbage so I cut one this week and, after taking off the outer, damaged leaves, I was left with a good, white cabbage that weighed about 700g, smaller than the 2kg quoted by most catalogues but perfectly acceptable. I did wonder if the small size was down to clubroot but when I pulled up the plant there was no sign of it so ‘thumbs up’ there.
When I grew cabbages in the same bed last year (the plot was dug and mushroom compost was added) I had a severe clubroot problem (below). *
This is hardly conclusive but it does seem that if clubroot is preventing you from growing cabbages these new hybrids are a good option.
PS. Just out of interest, I planted some ‘Kalibos’ cabbages in these beds too. This was partly as a control and also because it is my favourite cabbage for summer coleslaw – it is a summer red cabbage. So far these are not showing signs of clubroot either – odd. I will update this post if I find any clubroot over the next few weeks.
* This sounds like I have not heard of crop rotation but I will allow myself to plant cabbages in the same bed because a) it is a large bed and the cabbages were not in exactly the same spot and b) I only planted a few. But I will not plant cabbages in the bed next year now that my experiment is over. The bulk of my cabbages were planted in a completely different part of the garden.