(PS it's been interesting to be on the receiving end of the worried PPrune instant reaction 'oh, you can't do that, it's illegal/dangerous...' when that wasn't the point of the question!)
The trick is to include in the initial post "BTW, I've already addressed runway length, rule 5, and whether I'll upset the neighbours or not" -tends to head things off a bit.
As to the grass, virtually no damage at-all so long as it's reasonably dry. Probably some tiretracks that'll be visible for a few days only - particularly if there's a decent proportion of clover in the grass, which most playing fields should have.
G