[woodburner]

Goosegirl, When I took up the allotment I wasn't expecting this problem. I expected that I would have to remove turf\weeds turn the soil and then I can Plant.
I wasn't expecting to have to do so much digging just so that my plot stays above water.
I don't want to be digging the entire plot while every one else is planting ready for spring.
I go to the allotment on the Sunday and do digging for 5/6 hrs. The rate of progress means that I can't see that the whole plot would be ready for the start of the growing season (March).  I hope that the growing season doesn’t pass me by.
I have some garlic, shallots, flower bulbs I wanted to put in but I can't because I have no dry land, so I am already starting to fall behind.

Not everything needs to be sown/planted out in march. Many things can't be planted out until after the last frost, brassicas only need a seedbed, not a whole plot, for the first weeks, carrots, peas and saladings amongst others can be sown successionally through much of the growing season, so please don't lose heart. Remember too that clay based soils are if not THE best, then very close to the best for growing veg.

I've been thinking a bit more about your site and double digging. Whilst there is a lot to be gained from double digging, I don't think there's a lot of point until it's drier.  The point of double digging is to break up the subsoil a bit, but as it is so wet that the underlying clay is actually plastic, it is impossible to break it up, therefore no point.

[CARROTTCRUNCHER]

How many plots are there on your site and how is your plot situated is it near a ditch . and how much would you be prepared to spend .you may be able to put land drain in yourself or if you can get a tractor on site and your near a ditch you could find an agricultural contractor to mole plought it but it would need to be done every couple of years . if it was me i would go for land drainage . good luck CC,

[karooba007]

Whether you had the clay pan or not you would still need to double dig to get the best results.
Its part of growing veg no mater what the soil is like.

Ok, I now realise the digging was unavoidable. After all this digging I better have a dry plot 

[penance]

Don't forget its winter!
My garden is a soggy squelching mess this time of year but fine come spring. My raised beds are 10" high, thats enough for good drainage even with the clay below.

[penance]

No, dont bring the subsoild in to the top soil.
Read back and see what people are suggesting.

[Jeanieblue]

Hello there, Karooba. Our plot is on clay soil too and half is waterlogged at the moment. And remember you've had awful weather to contend with over this past year or two. Lots of more experienced gardeners than us have had problems with their crops. Do consider raised beds. We only have four at the moment- only started last year - I put a couple of sacks of cheap compost in them, and the soil  is even now drained and workable. Am definitely going to work towards raised beds on the whole plot. Better to have less growing area that is workable. Because of the wet conditions, most of our potatoes rotted in the ground last year. But we weren't the only people to have problems. I'm thinking of planting them in containers and then using the spent compost to improve the soil.  Raised beds needn't be expensive - my son had a brain wave.  From old pallets, he made me a 'raised bed kit' that I could carry down to the lottie section by section. Each section looked rather like a headboard - two planks deep, with posts each end sticking out an extra few inches to make 'legs' to hammer into the ground. So I have a couple of smart raised beds, approximately one headboard wide and two headboards long !!!  And I can make the beds as long as I like. It means I'm not standing on the soil in the beds and can reach in all the way round, so that the soil doesn't get compacted down.

So hang on in there,and the best of luck.

[andreadon]

All of my soil is clay.  with massive pieces of flint stone in it.
Great fun (I've never used my spade because it won't go through it!)

I think you should start with one area at a time and plant the veggies that need to be planted now/march (as suggested on an earlier reply).
You'll want to dig that area first and work lots of compost in it (maybe a bit of gravel?).  maybe raise it by a spade's depth too.  Then whilst those veggies are busy growing, you can do the next area the same way. 
That way, by the end of the year, you'll have loads of areas that have been worked and are nice and fertile.

I liked the idea of putting green waste in the bottom of your trenches.

I use my flints as borders around the areas I've dug and planted and they're growing in number!

[GreenOwl]

Will I need less fertilizer because I have clay? Will my plants grow bigger and should I bring some of this clay up to feed the plants?
I have decided what I will do with the plot. I will dig a drainage channel along the length of the plot, against the road (as shown in the picture). I will dig this channel until I reach the clay. The vegetable squares I will dig until I reach the clay, then I will fork the clay to remove hard pan and soften the clay (maybe also bring some of this clay up to feed short root plants). I will line the bottom of these vegetable squares with 2 layers of bricks to raise them. I will connect these vegetable squares to the drainage channel by creating a route for the water under the footpaths.
I have found a skip full of old bricks, just need to find someone with a van I can hire.

Nooo.  Clay-based soil is fertile but it is not fertiliser.  It does have nutrients in it (more than my free-draining stuff) HOWEVER clay subsoil is not fertile.  The plasticine stuff is the subsoil.

Sorry if we've confused you.

[woodburner]

I hope you don't mind me bumping this thread.
From what you say elsewhere, and that the ditch(es) isn't helping I think you may have a spring!
I think you have the right approach with raised beds, but before you go to the expense and effort of wood frames, can I suggest you make lazy beds on the whole plot? This will provide you with the extra height that you need for the beds as well as providing drainage for the plot at no expense. With a bit of luck you will actually see the water moving and might even be able to tell where it's coming from!

To make lazy beds you dig out paths and put the soil on the beds. I'm rather mean with my paths, (1ft) so in effect I have a ditch every five foot. I also have paths crosswise making the beds 4ft by 4m (I have a foot in both camps   ) My beds run across the slope to deter run off, but I suggest you put yours running with the slope. (If you can tell, that is. Your plot looks almost level from the pic.) Be careful not to dig so deep that you get the yellow subsoil on the beds.

They should look something like this.

It may well look likethis (scroll half way down the page) until the ditches all join up, and the water can run away though.