Plasterer's sand and clay soil

sussexbaker

Hiya

We've been left almost a full bag of plasterer's sand after having our house replastered. I know that you can add builder's sand to clay to help improve it, and I wondered if it was worth doing this sand?

Thanks

yoyoegg

TBH, one bag dug into the ground won't make a jot of difference (unless it's 1 tonne bag...). But you really need sharp sand when making up a potting compost.

Leif

The issue as you probably know is whether or not it is washed. If not, then you could be adding salt or lime to the soil. My neighbour told me that sharp sand is washed, and is much cheaper than so-called horticultural sand. Plasterer's sand is much finer, and I suspect it should not contain salts. Here is a useful link:

http://www.gardenadvice.co.uk/howto/lawns/lawn-rescue/index.html

As you can see, they suggest using it on lawns, so it must be salt free.

sussexbaker

Hiya

Thanks for the replies. I didn't think it'd make much of a difference, to be honest I'm clearing out and wanted to get rid of it. My wife dug the front garden up last year and that's hopefully having the frost go to work on it at the moment, so I wondered about throwing it on there (as it might make a difference on a small area like that). However having read that advice I might keep it for the lawn restoration.

Conrad

This type of sand will make a clay soil even worse as it already contains very fine particulates!

You would not really want this on the lawn unless it has quite large grains similar to sharp sand.

I used about 1 ton of sharp on a front lawn (about 40x40ft).

Clay soil needs absolutely masses of sharp sand and well rotted manure - really tons of it, if you want to make a real and lasting difference. Thereafter you need a thick annual dressing - no need to dig it in.

I often see people sprinkle a couple of inches on top, but if the clay soil is say 3 ft deep then your only addressing a small percentage of the soil.

Mollymoonlight

Conrad wrote: »

This type of sand will make a clay soil even worse as it already contains very fine particulates!

You would not really want this on the lawn unless it has quite large grains similar to sharp sand.

I used about 1 ton of sharp on a front lawn (about 40x40ft).

Clay soil needs absolutely masses of sharp sand and well rotted manure - really tons of it, if you want to make a real and lasting difference. Thereafter you need a thick annual dressing - no need to dig it in.

I often see people sprinkle a couple of inches on top, but if the clay soil is say 3 ft deep then your only addressing a small percentage of the soil.

I agree with most of this, except for the part about the manure. Unfortunately manure is heavy and moisture retaining in the same way as clay, so that too would make the soil worse. The only thing I've found that helps is sharp sand and leaf mould, but you need a lot of it. I would keep a hold of your sand for laying slabs or stick it on freecycle.

Mojisola

Mollymoonlight wrote: »

I agree with most of this, except for the part about the manure. Unfortunately manure is heavy and moisture retaining in the same way as clay, so that too would make the soil worse. The only thing I've found that helps is sharp sand and leaf mould, but you need a lot of it. I would keep a hold of your sand for laying slabs or stick it on freecycle.

I've got to disagree with this! People have been improving clay soils by adding manure for generations.

http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=620#section3
Five steps to improving clay soils:
Make raised beds to assist drainage and to reduce trampling of the soil
Consider adopting a ‘no-dig’ regime, especially in raised beds, as these suit clay soils well
Some, but not all, clay soils respond to extra calcium, which causes the soil particles to flocculate (clump together). Where the soil is acid, lime can be applied, but elsewhere it is better to add gypsum. Gypsum is the active ingredient of many commercial ‘clay improvers’. Test on a small area in the first instance to ensure it is effective on your type of clay
Dig in plenty of bulky organic matter such as manure or, ideally, composted bark, as this can make a noticeable improvement to the working properties of clay
Apply organic mulches around trees, shrubs and other permanent plants as these will reduce summer cracking and help conserve moisture

Mollymoonlight

I stand corrected...As I have a very expensively run manure machine (which goes by the name of Lolly), I can obtain scarily huge amounts of the stuff. In our last place that had heavy clay I was going to do this but I was told not to because it could make the situation worse for the reasons I quoted. Could it be because our drainage was particularly bad? I am sure the RHS know way more about it than I so I will concede and make a new note in my journal. Thanks for the correction Moj.

Leif

Yes, all the books recommend organic matter to improve clay soil. Pony poop is ideal although the raw stuff could burn some plants, so probably best rotted down. I suspect the raw stuff might have a lot of viable weed seeds in too, depending on the time of year.

Mojisola

Mollymoonlight wrote: »

I stand corrected...As I have a very expensively run manure machine (which goes by the name of Lolly), I can obtain scarily huge amounts of the stuff. In our last place that had heavy clay I was going to do this but I was told not to because it could make the situation worse for the reasons I quoted. Could it be because our drainage was particularly bad?

It is possible to over-manure. Maybe Lolly's production was just too much for your ground!