Green manure

[Vince G]

Anybody grow/use this? I've grown caliente mustard on one plot on which I'm going to be planting the onions I've started off in modules. Srated chopping digging it in this afternoon. Thought it might be a decent fumigant but not sure of any other effects. All views welcomed

Also got a little patch of phacelia which I'm going to dig in to next year's potato bed with some horse muck

[ameno]

A certain consumer magazine did tests on caliente mustard a few years ago.
Apparently the fumigant effect does work (within reason, anyway, it's not a miracle cure), but it needs digging in as soon as possible after chopping it down, so as to trap the fumigant compounds in the soil. If you leave it even a day after chopping before digging it in then all the fumigant compounds will have just dissipated into the air, and you'll be left with just normal mustard.

[Penellype]

I've tried caliente mustard and buckwheat. The mustard got to seed leaf stage before it all disappeared (slugs). The buckwheat was marginally better although I would say maybe 10% of the seeds managed to get past the seed leaf stage. However, I was expecting buckwheat to be about 18inches high and produce a "lush carpet of growth", but all I got was scattered 2-4 inch high small plants which then started to produce flower buds.