Topic: Soil conditioner for heavy clay

[darkbrowneggs]

Hi - I am on very heavy sticky clay here, though once things get going it is a good rich growing medium

I read years ago in one of Lawrence Hill's excellent books to get Gypsum and Magnesium limestone mix the two together at 4:1 and sprinkle on the soil

It has some kind of chemical reaction with the clay and encourages the fine particles to bind together and make the soil more friable

Previous to that I had put on absolutely masses of FYM and spent mushroom compost to very little effect

It is not an instant fix but after 2 or 3 years there is a really noticeable improvement to the soil structure.

Well it worked for me anyway :)

All the best
Sue

[Unwashed]

That's right as I understand it too - lime helps clay soils floculate, and limestone is better than garden lime as it doesn't leach out as quickly.

But I'd suggest the very best thing for a heavy clay is dung - lots and lots of dung.  And don't walk on the soil when it's wet or it'll lose its structure.

[galina]

Before using lime you need to check your soil ph.  We are sticky, heavy clay, but very slightly on the alkaline side of neutral.  Lime would make it worse.

I haven't tried it yet, but have been recommended to get a lot of sand to make the soil lighter and break up the clay.

Dung sounds good too if you can get it.

[1066]

I added some Mushroom compost to a couple of beds on my plot this year, it will be interesting to see what, if any, difference it has made to the clay  :-\

[darkbrowneggs]

Sorry  - in my first post I meant to day Dolomitic Limestone (which is of course a magnesium limestone)

All the best
Sue

[daitheplant]

Lots and lots of humus. I wouldn`t use sand at all.

[elvis2003]

sand will make clay soil far worse,dont do it!!!! organic matter,as much as you can,is best for this type of soil,all your veg waste from home and manure.Doing this will create a better balance of air,water and  minerals .

[Ellen K]

Well, if you have got a lot of clay, what you have to do is dilute it with something else.  That is the long and short of it really.

Another thread has appeared today about sieving the soil to make it "compost like".  

To my mind they are both wishful thinking.  You might get a temporary effect (maybe, if you are lucky) but the solution lies in changing the composition of the soil.  With good stuff, I mean.

[Unwashed]

On the up-side clay soils are good, being fertile and holding nutrients and water well so once you've got some humus worked in and got a bit of structure to it you're made - it's just clay soils aren't the easiest.

[Deb P]

Also on heavy clay here in derby, agree about ading Mushroom compost (which contains a small amount of lime) and manure, but I also found Calcified Seaweed to be of great value in helping to break up clay. You could have made pots out of the clay I was digging over in 2006 (well, it did used to be a brickworks at one time!), but year on year of using everything I could add in the soil has made a great difference. You can also buy claybreaker pellets to help break down the clay, I was given half a sack by an outgoing lottieholder, and used it on my newer half plot with good effect.

[Russell]

I would like to support the positive statements about manure etc and also the negative ones about sand. One of my neighbours has added lots of sand and gravel to his plot and his crops have suffered.
My speciality is badly made compost. I put lots of wood chip in it. It works well.
Can I also add that digging matters. Turn over in big lumps in autumn and leave to drain. I am trying a bit of double digging. So far I think it's not wrong but it's too soon to say that it's right.
And of course never walk on your plot when it's wet and as little as possible when it's dry.

[Ninnyscrops.]

Horse manure one year, cow manure the next and spent hops as a mulch every year from Mrs Claggy Clay 2005 - the combination worked for me  ;)

Ninny

[Vinlander]

I'm on heavy clay and lime is essential to remove the stickiness - for one thing it makes it a hell of a lot easier to include humus throughout the soil.

You can use lime with moderate quantities of well-rotted compost.

But if you're using manure you need several months between it and the lime or all the precious nitrogen will leave as noxious ammonia gas.

One way around it is to use gypsum - it is completely immune to manure and doesn't change the pH - but at a ridiculous price - I can think of no good reason why gypsum is more expensive than the plaster that is made from it (burning a lot of fuel in the process).

I'm sure it makes someone lots of money but it makes no sense.

Has anyone tried using pulverised plasterboard on clay? I'm going to try it when I have time but it would be nice to know it's worth the effort!

Cheers.

[jennym]

My old mum says that they used to use "ceiling rubble" on her plot, but whether that was the same as plasterboard, I'm not sure.

[aj]

I use sand on mine; mine is subsoil as the nurseries across the road stole all the topsoil when the allotments were not being used; the sand helps to break up the soil. Also, use cardboard as a mulch and plant through. The cardboard breaks down and gets drawn down by the worms. And, anything else really, manure [although I got stung with aminopyralid last year so never again for me], coffee grounds, home made compost, comfrey, newspaper; anything really.

We dug over a bit of the plot last weekend; most of the clay was sticky and horrid but the bit that I put sand in 2 years ago for a carrot bed was lovely to turn over.

Scientifically; RHS say that soil needs the following constituents:
Air - 25%
Water - 25%
Minerals [which is sand, silt and clay mixed] - 45%
Organic matter/humus - 5%

So it's fine to add to clay; just don't add too much or you negate the beautiful nutrient holding qualities of your clay.

[1066]

I'm guesssing that could be the old stuff - we have a few ceilings in our house that have that, wonder what the Conservatiion Officer would say if I pulled them down to use on my plot  :D  ::)

[vcatkinson]

Manure is the best to improve clay soil over time it helps improve soil structure, clay soil is good for growing with manure, chicken manure is the best but i find cow manure or horse ideal best to let the manure rot down first as it can be to strong neat, or on bare soil soil can be dug and manure left over winter to break down then dug in in the spring.I garden on clay soil but also has slight loam content and manure which we do not manure every year. Or like others suggest raised beds could be easier and ideal.
Also you could also check your Ph first to see what Ph your soil is  and soil testing you can generally tell by rolling a ball of soil what it is made up of eg.if it feels gritty sticky , this will help to establish problem.
Victoria

[Vinlander]

My old mum says that they used to use "ceiling rubble" on her plot, but whether that was the same as plasterboard, I'm not sure.

All plaster starts out as gypsum - actually it was and still is "calcium sulphate" but the solubility changes dramatically depending on how much water is driven off when it is roasted to plaster.

The article I read said that most plaster will contain a substantial amount of the original formula and should therefore do the trick - though you may have to use more.

I suppose older plasters might be less roasted and therefore better? who knows? They certainly had horsehair in (for strength - instead of a paper covering) which would make it a fertiliser and soil conditioner in one.

Since plasterboard's free from skips you can use loads - the hardest part will be grinding it up - and every kind of  calcium sulphate is harmless in or out of your soil (unless you bash someone over the head with it or make a dagger out of plaster or load a shotgun with it...

Though of course no dry mineral dust is ever safe - so do your grinding wet.

Cheers.

PS. I've been using strips of plasterboard over early winter broad bean sowings - might fox the mice a bit - but you need to check regularly and make sure it comes off as soon as the shoots emerge or the slugs will capitalise on the moist sheltered diner you've created.

[Robert_Brenchley]

Gypsum's a natural ingredient of clay, formed via a series of chemical reactions from sulphur in the proteins of organisms which became buried as it was deposited.