Janet Baraclough wrote:
The message
from Derryl contains these words:

Don't use sand it will mix with the fine clay and make cement and ruin
your good soil.

No, it won't. Not in the UK, where Theo is posting from.

Indeed (though Derryl wasn't replying to my post). There isn't enough
calcium content, and any reactive material that has been exposed to the
elements will already have been hydrated so won't be able to undergo the
hydration reactions that set cement.

Cementation will eventually happen with a calcitic pore fluid crystallising
around the grains but this is likely to happen under pressure once buried
and over thousands of years, so not a problem for most gardeners.

Theo