Septic system question! How important is the last eighteen inches of pipe to the system's continued functioning? And can I grow crops there?
On our tiny farm we have a tiny greenhouse -- 10x20'. This is designed to accommodate two four-foot beds or tables along either side. So far we have just been using tables for starting seeds, but now we'd like to do a raised bed along the south half. We will need to line it with hardware cloth along the outside edges, extending the wall down into the ground 2 feet for rat-proofing, so I have been planning to dig down about 2 feet the whole way. I started this process and didn't get very far before I ran into the tail end of a ~4-inch perforated PCV pipe, which I assume is part of the septic system.
The part of the greenhouse in question is located at least 50 feet from the top of the septic system -- don't know what it's called -- the part where lid is, and the system can be accessed for cleaning etc.
I'm wondering two things. One, can I safely just saw through this last 18 inches or so of pipe and remove it so that I can line with hardware cloth as planned? Will this mess up the septic system? And two, can I then safely eat crops grown in a raised bed (adding probably 12 inches of topsoil) in this location? We hope to do greens and leeks etc in the winter and cucumbers, tomatoes, and melons in the summer, so ideally it would be both leaf crops and fruiting crops.
One thing we considered is to switch sides -- to put the seed-starting tables on the south side, the one we were planning to dig out, and the bed in the ground on the other side. But the north side has a large hedge about 15 feet away and gets less sun than the south side obviously, and I also would worry that the tables would then block sun to the bed. I'd rather have the bed on the south side if possible.