"Dave Hill" wrote

I just worry that if it wont grow grass well then you will have the
devils own job to grow good veg.
If you rotavate you will be creating a pan about 6 to 8 inches down
that will stop any water going through.
Your only hope is to hand dig, throwing the soil up so as to leave a
trench around the outside to help with drainage. The deeper you can
dig the better, though it will be hard work.
If you can work in organic matter so much the better..
Once you have dug then you can use a rotavator to get a working tilth.

Others on here have said in the past about rotavating causing a pan but it's
never happened on our allotments because in digging up the spuds, parsnips,
carrots etc and putting in stakes and poles and digging holes for compost
for pumpkin planting etc any potential pan will be destroyed.

--
Regards
Bob H
17mls W. of London.UK