Okay, I extracted more info from Ray this morning. ;-) Apparently the
slabs were real paving slab size - around 3' x 2.5' and they were buried a
yard below the apple trees' roots. I asked him how he had learned about
this (because I'd forgotten) and he said that 'old Tom' who used to work for
Ray's family nursery in Essex had told him. Old Tom had actually done the
digging and laying of the slabs for dozens of apple trees in his time.
--
Sacha
www.hillhousenursery.co.uk
South Devon
(email address on website)