Need to kill off all old weeds/grass so I can lay new lawn
 

Hi all

This is my first post so please go easilly.

Last year I suffered badly with a poorly drained garden because of a massive tree stump in the middle of the garden. Well, after a full Bank Holiday weekend/1 digger/4 guys, we finally got the giant stump out. Of course at the same time, and as advised elsewhere, I dug 2 feet dep chanells in the garden and filled them in with fresh top soil/sharp sand mixture. The drainage has improved a lot, but here is my problem.

All that took place at the back end of summer, and since then I have just left the garden alone, because I was told it was too late in the year to lay a lawn. Now, the garden is a mess. Weeds, Nettles, Thistles and thin and thick grass have sprung up all over it. Basically, I need to kill the lot off in one go and flatten, roll and prepare the garden for new turf. Please don't advise me to hand pick the weeds/grass etc, because the garden is far too big for that. So, my question is:

IS THERE A COMMERCIAL PRODUCT THAT I CAN SIMPLY POUR ON THIS GRASS/THISTLES/WEEDS ETC, THAT WILL KILL THE LOT BUT WILL NOT DAMAGE ANY FUTURE GRASS/LAWN?

Thanks all.