The peat/sand mix is around 8 inches deep, they have a very shallow root system. I tend to ignore it, if we have a hot dry spell I will wet it down real good, then ignore it for weeks again. The plants like the wet / dry cycle. I get it wet enough there is standing water. I did not put holes in the tarp to help it drain out. The bog garden is in full hot sun and dries out without any help.
2 - flava yellow
3 - flava ornata
3 - swaniana
3 - catesbaei
2 - rubra
2 - minor
2 - flava
2- purpurea green
2 - dana
2 -Scarlette Belle
2 -Judith Hindle
2 - Purpurea red
3 -Tarnock
2 drosera filiformis
2 venus fly trap
This is what I started with the fly traps did not make it through the winter. All else doing fine so far.
I use well water, ours is very soft but acidic. The plants like acidic water, I don't think hardness is a issue, but no clue really. The peat keeps the soil nice and acidic.