Green Manure on Clay soil

[Moggle]

I feel really stupid, but I am really having trouble getting my head around the whole clay soil and overwintering green manure thing. I'm hoping that someone will be able to help me understand it all better.

Right, so I have heavy-ish clay soil, hasn't been cultivated for at least 3 years. I have dug over a bit as recommended by the site secretary, in big clumps, for the frost to break down. I will do more digging over the next few weeks, and have 2-3 beds roughly dug. The overall level of the plot is quite sunken, as much as 6-8 inches on one side.

I would like to try out some green manure (grazing rye) on a couple of the beds if possible.

I am 90% certain of getting a big bunch of leafmould in the next week or so.

What would be my best course of action with green manure:

1- none - roughly dig in the leafmould and let the frost and winter do the rest of the work.
2 - chop up the clods, and add leafmould at the same time, then sow green manure.
3 - chuck leafmould over top of the clods, then sow green manure, then dig everything in really well in the early spring.
4 - Something else entirely.

The beds where I want to grow the green manure, will be used to grow Garlic, Onions from seed, and onions from sets, and the other bed will be potatoes.

Hope this all makes sense and I haven't rambled too much and left something out.

[gavin]

I'm not much help, Moggle - I'm at the same stage as you, just digging over my overgrown clay just now.  

FWIW, I'm doing your 1;  just rough digging - and I've a load of horse manure ordered which I'll spread (or dig in any digging I do after it arrives).  A small chunk rough dug back in July has broken down nicely (much better than the bit I skimmed the sod off - but I do have a huge sod pile, that'll go back into the beds next year ).  Even stuff I dug last week, is already breaking down.

But just a couple of thoughts on grazing rye - it's supposed to be excellent for breaking up soil, but very, very tough to dig in later on.  The idea of making the digging worse was enough for me to pass on my packet of seed to somebody else (who I haven't seen since - wonder if that's a sign?).  

Also it inhibits germination for other seeds for a couple of weeks or so after you dig it in - so OK for potatoes and sets, but not your onion seed?

Good luck - Gavin

[john_miller]

The ideal, Moggle, is cultivate and sow green manure. The advice to dig and allow frost to break it down is a combination of economics (in your case will you lose money if you break it down manually as you may have to give up some other money making enterprise, a farmer may have the same problem or pay someone to do it) and the sheer practicality of cultivating heavy clay soil when it is probably sodden (and so heavy it may even be a medical issue too!). It is not seen as the best practice nowadays but may be your only course of action.
You do realise onion seeds can take 6 weeks to germinate? You might be better sowing in modules and transplanting.

[Moggle]

Thanks John and Gavin, you've both given me plenty to think about.

I will keep pondering, and seeing what the weather does, and see how i get on with the rough digging, and in the end I will probably try both leaving some beds rough dug to break down, and I will give the green manure a shot on at least my potato bed.

Thanks both for all your advice