"Chris J Dixon" wrote in message
...
Having just extended a flower bed to incorporate what has been
lawn for 40 years, I am left with some pretty solid clay soil.

Gypsum is recommended as a soil improver, but appears to be sold
in garden centres as a proprietary product costing nearly £5 for
2.5 kg.

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

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

Any reasons not to go with plaster?

Chris

I don't really know the answer to your question, but I would warn you not to
use gypsum if you want lime-hating plants such as heathers, rhododendrons
etc

R.