Install first layer of 4 inch perforated corrugated drain pipe (ADS)

You can see I've brought a lot of fill in and the East, West, and South have all been built up to about 18" from the bottom of the hole. The North side will be ramped up as I fill so the truck can back up and dump there. On the East and West I've installed some posts and wooden horizontal members to hole the end of the 4" ADS in place while I backfill. It's about 18 inches from the outside of the greenhouse you'll see why later. I cut each 4" to length and put a screw in each to hold them 18" apart. I don't think this needs to be perfect so done is perfect here.