The cinder blocks are ~8" deep. I figure the average height of the river rocks will be ~5" tall. I'll dig out the bottom about an inch so I can remove some plastic sheeting that's under the gravel. With a 2" cap, I expect to have 6" of growth medium. I'm thinking the bottom 4" will be filler dirt and some dried leafy material. The top 2" will probably be a mixture of mushroom compost, steer manure, vermiculite, perlite, raised-bed soil, and potting mix. (It's what I make for the potted flowers and vegtables.) Then when planting season starts, I'll cover with red mulch for the tomatoes and brown mulch for everything else.
I'm doing open-air compost for leafy yard waste, egg shells, coffee grounds, and fruit peels. I'd like to get a rotating composter, but the decent ones are ~$200.
I thought about a soaker, especially since my rain barrel is only about eight feet away. It's also about four feet higher, so gravity might be enough to push through. In the end, I decided to just hard-water the bed.
Is the soil you put in going to be a full 12 inches deep? It looks about that deep. I've got a less elegant bigger set up, but I am going to be putting in an underground soaker hose and topping it with loam for a raised bed type thingy. Unsure how deep to go with the loam, complicated by the fact in the spring I'll move the compost there and top again.
