What sort of Soil Is Greatest? Venus fly traps prosper in damp, acidic, nutrient-poor soil. To recreate it indoors, use a one:1 mixture of peat moss and perlite. A mix of soil mix with peat moss, or horticultural sand having an equal level of peat moss also will work properly.Potting a Venus Fly Trap Due to the fact Venus fly traps are fickle with