Soil PH & building sand

Hi, after some rennovation work to my house a lot of 'building' sand has come into contact with an area I'm hoping to plant up. The soil in this area is generally a slightly acidic clay. Obviously the sand will help with drainage but how will it effect the PH ?
Cheers in advance.

 

Hi naepace. There are two types of sand - sharp sand which is angular and abraisive and is used in concrete, and soft sand (often called builders sand) which is used in mortar. Do you know which one you have? The sharp sand is good for drainage, because it is sharp and doesn't clog. The soft rounded sand won't help much with drainage.

I have just put my pH meter into a bag of wet sharp sand and there was a tiny increase to 6.7 compared to my compost mixture of 6.6. So there is really no effect. This is a neutral value and the measurement was really that of the water rather than the sand. This is what I would expect as sand is just insoluble particles of rock - mainly silicon dioxide.

 

naepace, the problem with using builders sand is the salt content, this can be detrimental to the soil and, more importantly, your plants. I would advise against using it.

 

Sand and clay can also make an almost impermeable mix :(

 

dai - I don't think there is any salt - in sharp sand at least. It doesn't come from the sea. The action of the sea will make the sand very rounded and soft and disqualify it as sharp sand. I have spread several tons of sharp sand on my clay, along with small gravel and organic matter. And it has improved it a lot. I also use one third sharp sand (all from the builder's merchant) in my potting compost mix. It seems to do well.

Soft sand may well come from the sea, but I think it is all washed. Salt in mortar or bricks will leach out in time leaving disfiguring white deposits on the surface. I used to live in an old house with bricks made with a high salt content - and it made a right mess of the surface of the house. I am sure building regulations would not allow that now.

 

Peter, if it`s sharp sand then I agree with you, but if it is ordinary builders sand then it will cause problems.

 

I'm pretty sure soft sand doesn't come from the beach, at least around here its dug from sand pits, presumably sand deposits layed down thousands of year ago.
As to what salts it may contain probably depends on the local area.
I was told once, that soft sand contains some clay, thats why it tends to "set" when dried out and goes sticky when wet.
Have you seen some of the new brickwork these days Peter, masses of salts leach out on certain bricks, (not sure what they call it now).
I've always used sharp sand from builders for adding to my compost, horticultural sharp sand is far too expensive.
As to the soft sand, I think its more a problem of how much, rather than if its actually harmful in itself.

 

Slightly off topic but I did get a quote for agricultual grit from my local builders yard for about �£70 per ton. Which is not that bad but still double the cost of 10 mil gravel. So I have used that instead to add to my clay, along with sharp sand. Sand, gravel and compost plus digging really does make a differance to heavy clay. I can now just push my fingers into the soil to plant things. Then 18 inches down I buried piles of newspaper. I expect my more highly bred cultivars to be able to reach down and read the three year old headlines. But I don't suppose the common plants will bother. :D

 

We have an agreagate merchant/distributer down here. �£20 per ton Stone dust, �£15 per ton building sand, �£25 per ton limestone chippings �£35 per ton flint, �£45 per ton slate.

The building sand is dredged rather than mined.

 

Thanks guys. It is sharp sand so I guess it'll be fine.