Poor Drainage

[cacran]

My allotment used to be swamp land, or so I am told.

The soil is very heavy and really hard clumps.The clumps are hard to break up.

I got hold of a lot of sawdust( from a Rabbit Breeder,) full of Rabbit poo! I spread in on a number of my beds during the Winter months. I have dug it in. Was that a good idea???

We have a lot of Sharp sand left over from concreting the drive. Could I use that in my beds to aid drainage?

[cacran]

[ACE]

If it was a swamp and is now dry it seems as if the ground was drained at some time. If it still wet and unworkable in the winter a French drain will help. Dig a trench deeper than your usual planting depth and fill it with all your stones or any rubble you can get. But if it does stay dry, loads and loads of manure over the next few years to lighten the ground up. I had the same problem on a plot I used to have, I ended up using raised beds which I could have had no dig, but I used to turn them over in the traditional style.

[ancellsfarmer]

This may be of interest:
http://mapapps.bgs.ac.uk/geologyofbritain/home.html?location=RIPON&gobBtn=go

Somewhere convenient, dig a hole. Go down till you hit 'rockbottom'. If you get to a layer which appears as a greenish* purple, with recognisable vegetational fragments, that will be a compressed layer where anaerobic decomposition only was possible. The bottom of a swamp/pond/fen/ditch.
*vivianite mineral
This will give you an idea of the general situation. However, so long as the topsoil drains away somewhere, horticulture will be possible. Management is the key.

[Vinlander]

Raised beds have the advantage that they can be used even when the water cannot be drained away because there is nowhere for it to go except down.

They also warm up much quicker than soil nearby but up a gradient (so it isn't showing water) - I find that beds raised 25cm above the water level still drain and warm up much faster than soil that is 50cm above above water level - mainly because the rainwater is coming down that gradient and running through that soil - and what's worse it is running through just below the surface. 25cm raised beds also seem to be be doing better than soil 1m above the water level - difficult to say with such small differences - they are certainly not noticeably worse.

NB. when I say water level I mean water I can see flooding the paths between beds in winter...

Cheers.

PS. My raised beds were made by simply digging the path down to subsoil and chucking the soil on the bed before filling the trench with prunings, branches, disintegrated planks (not tannalised), woodchip - whatever is available that won't compress to nothing that year and isn't much use in the soil until it does. Other dugout paths in land that doesn't flood contributed soil to beds that would.