My husband and I are going to be constructing a raised bed garden at our new house and I was wondering how extensively you have to prep the ground beneath? I assume you need to dig up the ground to remove the grass but do you have to dispose of the grass layer or can you just break it up and work it back into the soil? We plan on adding about 12 inches of new soil on top of the existing ground. If we do need to remove the grass entirely from that area, what do you do with all that extra? dirt/grass?
I did the same thing as far as depth when I built my 4ft. x 12 ft. raised bed. I dug up the sod, removed it entirely, turned the ground with my shovel and broke it up with a hoe to a depth of about 6 inches. I got some top soil from a local distributor and hauled it home in my pickup truck, saving me at least a $50 delivery fee. I found the soil they sold to be a bit lacking so I put in a good bit of my compost to boost it a bit.
I am now getting some bermuda grass coming up in places but it is not enough to worry about. I do not use a fabric cover but plant directly in the soil and mulch once it is planted to keep weeds and help save on watering.