community garden question

 Our church is starting toward a community garden. We'll have a 150'x75'
plot. Our garden is going to go in a big lawn.
We know we should either push off the grass or we'll be doing weeding later.

However, I'm wondering if there might be some kind of grass poison which
will not effect anything except the grass we could use?

 
You can kill all the vegetation with Roundup (glyphosate), but it must
be actively growing, not dormant.   You'll still have all the clumps
of dead turf to deal with.   If it were me, I'd probably kill and till
this year, then plan on planting next year.  That way you have less
work, as you won't have to deal with the dead turf.

 

Rent a sod cutter. It will evenly remove the sod, and with it, most of the weed
seeds that have collected over the years, waiting to sprout. You will end up
with a significantly more weed-free garden, and tilling will go much easier
also.

 
Right on!  I put 5 flower beds in a turf area.  Rented a sod cutter
for a half day, cut the sod, took it back, then came back & finished
the beds. Cut way down on the labor and had very little grass come
back in the beds.

Bob