[zazen999]

OK Zazen999 I'll defer to your experience, but I'd want to experiment with it first before using it myself.

SS

Thats the way to go. Sharp sand is far more grity and break's the clay down well. Soft sand (used for laying bricks) holds water as it is far more dense than sharp sand. Add growmore, sharp sand and see how you get on.....

I've explained that yes, sharp sand is BETTER - but if it is a case of no sand or any sand; then any sand will do. Once it is intermixed with the clay, it's not going to hold any water at all; it doesn't work like that when it is all mixed up.

[monsta]

ash is quite good to! or if its really bad you could digg the lot out and replace it with new top soil. or when no ones looking go down the beach and look at the sea!   

[richyrich7]

There's really no one easy answer I would take a multi pronged approach, plenty of organic matter, sand, and don't forget lime.
Lime alters the properties of clay making it form tiny clumps rather than laying close together.So there's more air and so more drainage it's called flocculation

Also don't forget a good rough dig before the winter, don't walk on it till it's ready & a good old fashioned double dig won't go amiss either  

[Kristen]

How much sand would you recommend? - in terms of depth of the layer added to the surface and then worked into the top spit perhaps? [I liked the idea of using it as a mulch the first year ]

Presumably it will stay in the top spit? or am I going to have to "top it up" now-and-again?

My soil is improving 3 years after converting from rough-grass-paddock and reasonably generous annual applications of well rotted manure / compost, but I would like to consider adding sand.

[zazen999]

Well, an 'ideal' growing soil is 25% sand, 25% silt, 45ish % clay and 5% humus....so up to 1/4 of the volume....if it is possible to do so. [reference - RHS, not me!]

I add it to the root veg beds as I move things around.

I also use sawdust as a mulch, my lottie neighbour gets huge bags from a woodwork place for 3 of us and I use it on every bed; it gets worked in by the gremlins in the soil and as I harvest.

Also with clay soil, it really is better to have beds rather than rows; as you can focus the additions on the soil you are using, not the soil you will be walking on.

[Kristen]

I do have "lazy beds" so not walked on, and the paths are permanent & lowered.

4" of sand on the roots beds will get the job done, and spread the cost, over 4 years.

Good plan, thanks.

[Faz]

I have very heavy clay in some parts of my patch. I have added plenty of manure all over, plus sharp sand/compost mix in the areas where I've grown carrots and parsnips, mainly so that I could get a ecent seed bed, but it has also made a significant difference to the properties of the soil. I can dig last years carrot bed already while the other bits of the patch are still far too heavy to dig over.

[DavidT]

DO NOT use builders sand. This is full of salts that you DO NOT want in your garden. If you must use sand , use horticulural quality. Better still, don`t use sand at all, use plenty of humus. This opens up the soil and gives it more bulk. It also helps retain moisture and nutrients.

[Faz]

Retention of both water and nutrients on heavy clays isn't really an issue, in fact the retention of water is the problem! Unless you don't want to be able to access the plot for significant periods of the winter/spring then some improvements in the drainage characteristics of the soil are desirable, IMHO.

[Slowgrind]

I'd give the builders sand a miss!
We use this stuff every day and it holds water for quite a while. As someone mentioned before this sand may not have been washed and contain all manner of salts! Horticultural sand doesn't cost that much extra.

[andtiggertoo]

I had large patches of very heavy clay in my garden and I added mainly manure to break it up but it did take several years. I agree that spent compost, your own compost heap and sand will all help( not getting into debate about which kind of sand). But i think it will take several years.

It depends how much of your plot is clay and how patient you are as to whether you want to address the problem over the whole plot. I think kristen's idea is good if you have a very large problem area. You could maybe put lazy beds or raised beds on half the problem patch. You can then fill this and get using it fairly quickly, then concentrate on the remaining problem bit following the advice above. It takes quite a lot of manure and compost material to make a difference on the clay area so the amount you have available to you is also a factor.

Good luck, you will get there in the end.

[theakston_uk]

I've got heavy clay soil on the piece of land I'm turning into an allotment. A friend of mine is in the building trade and has said he can get me something very similar to sharp sand called Mersey grit. It's basically sharp sand but it's got some salt in it, due to it being dredged from somewhere near the river Mersey. Not sure how much salt is in it, I'm wondering if it will be OK to improve my soil

[richyrich7]

Wouldn't have thought it was much good to be honest, the salt may well kill anything you try to grow until it naturally washes away with the rain.

[Jakell]

 Some good replies here, so I'm not going to add anything.

 I'm just curious about the history of your plot. If it is similar to those around you, then I would  have thought the other gardeners would be of most help to you. If it is different, then I wonder if there has been any excavation done on your plot, and some subsoil has been brought to the surface. This happened on my plot, the water board had to dig a 10ft hole to get to a sewer, they tried their best (under my supervision) to replace the soil correctly, but I ended up with some heavy clay at the surface. I had to mix this with the surrounding topsoil in order to render it workable.

[zazen999]

It's surprisingly easy to wash salt out of sand or grit.

Put in bucket.

Fill with water.

Leave it a bit

Tip water out

Fill again and tip out.

Job done.