Unified Soil Mix for Mixed Temperate Carnivorous Plant Containers

One mix serves all temperate North American CP: 40% peat, 60% perlite. Your 40/40/20 peat/sand/perlite is excellent. Separate mixes for flytraps (sandier) or S. psittacina (heavier for winter flooding) offer negligible benefits in containers. Perlite is safe if igneous-rock sourced (no fluorides). Sand adds weight—problematic for movable planters.

Large containers benefit flytraps. S. psittacina's winter immersion preference is better served by peat/sand weight in its own pot.