I'm in the process of clearing the garrden of my new house of a number of conifers. They (Leylandii or similar) have been there a reasonable amount of time. I'd guess from what I know about the propery about 50 years. Trees are approx 30 - 40 ft tall. Trunks up to 18"

I want to initially plant grass where the conopy of the tree was, but imagine the soil is going to need some significant conditioning first.

I've raked away alot of the old decayed leaf matter but still lots of fiberous material.

Can anyone recommend what to add and how. I was thinking of rotovating farmyard manure in, if I can get through the hidden roots?

Thanks

Nick