On 07/03/2014 19:15, Chris J Dixon wrote:
AL_n wrote:

Anyone advise which kind of bagged compost or esily-available waste
vegetable-matter or mineral is best for adding to very heavy clayey soil,
prior to sowing with grass seed? I'm going to need a a few cwt, so if it's
cheap, I'll be happiest!

Gypsum is recommended as a soil improver, but appears to be sold
in garden centres as a proprietary product costing over £6 for
2.5 kg.

http://www.capitalgardens.co.uk/clay...er-p-6321.html

On the other hand, I picked up a 25 kg bag of multi-finish
plaster for under £5, and AFAIK this is essentially the same
material. It worked well.

Chris


B&Q sell sharp sand labelled as "soil improver". Same stuff in a
different bag is a building product. To be fair though, same price!
It's incorporating the sand into the clay that's the problem.

My favourite improver is vermiculite, but I imagine fly ash might have
similar properties and be relatively cheap in bulk?