Soil_chemistry on echeveria
What's Happening
Succulents like Sedum employ Crassulacean Acid Metabolism (CAM) photosynthesis, storing water in specialized mesophyll tissue. This adaptation requires rapid soil drying between waterings to prevent anaerobic root conditions. Standard potting soil retains excess moisture through fine peat particles that compact within 2-3 months, creating waterlogged anaerobic zones below 2mg/L oxygen threshold even with careful watering.
How to Fix It
- 1
Mix soil at 1:1 to 2:1 ratio of inorganic grit to organic potting soil—50% commercial succulent/cactus mix plus 50% perlite or pumice for indoor conditions
- 2
Test drainage: Water should exit drainage holes within 30 seconds; if slower, add more perlite
- 3
Repot annually with fresh mix to prevent organic matter decomposition and compaction
- 4
Bottom-water only when necessary to control soil saturation levels
- 5
Monitor with moisture meter or wooden skewer—water only when probe comes out completely dry
How to Prevent It
Use 50-70% inorganic amendments (perlite, pumice, coarse sand) in soil mix. Select unglazed terracotta pots which wick moisture through porous walls. Allow soil to dry completely to 2-3 inches depth between waterings—typically every 2-4 weeks depending on season and light exposure.