My soil is compacted clay, with hardly any worms. Have decided to try double
digging the borders. Is this a good idea? What should I dig in - I've got
some sharp sand and compost. Will this do - I can't really afford grit .
Would appreciate any advice

Also what is the best technique for actually breaking up the great, hard
lumps. Hitting them with a spade just seems to make them harder! TIA,
Hayley