Plant onions after onions grown?

[Kristen]

I'm personally not an advocate of monoculture and have had problems on my plot with onion white rot ... I hate to think what my onion crop would have been if I'd grown them this year in last years white rot infested area.

I have seen it suggested that an alternative to crop rotation is mono-crop because then if you get disease you have clean soil to then use for subsequent growing.

I can see how that works, but for me a main reason for crop rotation is to vary the nutrients that are extracted. Whilst I could take the soil out, put in all sorts of compost/ingredeints, to improve fertility for mono cropping I figure I can do that on all my beds, and rotate the crops, to the same end. If aiming for the perfect soil for showing veg it might be different, but I think for a regular veg gardener improving the soil across the whole plot by adding muck / compost should work well.

I get volunteer spuds where I grew them last year. Quite apart from risk of disease, if I grew spuds in the same place my varieties would be mixed up with this year's seed potatoes intermingled with the volunteers, and I'd have All Sorts. At least with rotation I can rogue out the volunteers so that the next time that plot seeds Spuds there are no foreigners in the crop. In theory my Legumes put Nitrogen back, and I get a chance to sort the pH with Brassicas ...

But there again many people don't rotate their Runner Beans ... and I don't rotate my Rhubarb ... nor my Oak Trees