Which amendment prevents root rot better?
Written by
Nguyen Minh
Reviewed by
Prof. Martin Thorne, Ph.D.Plants die quietly from root rot when the soil is too wet. Perlite prevents this by creating air holes for drainage in the soil. Vermiculite can make this worse by creating excess moisture. I've saved countless plants with the right choice of amendment.
Perlite has a pore structure that drains the water away from roots, creating air pockets that the roots need to breathe. Vermiculite acts as a sponge, holding water. Any plant that dislikes wet feet will struggle in any vermiculite mixes.
Perlite Defense
- Creates drainage channels preventing water accumulation
- Allows oxygen to reach roots inhibiting fungal growth
- Does not break down maintaining structure for years
Vermiculite Risks
- Holds 3-4x water creating soggy conditions
- Compacts over time reducing oxygen flow
- Promotes root rot fungi in poorly drained containers
Match amendments to plant needs. Succulents require 30-50% perlite by volume. Moisture-loving plants handle vermiculite. I test the soil by squeezing a handful of it. If water drips out, add more perlite immediately.
Indications of problems begin at an early stage. In particular, yellow leaves suggest excessive water. Wilting shows that damage to the roots initiated the problem. Check the origins whenever the plants appear to be sick. Healthy roots are white and firm. Rotted roots will be brown and mushy.
Salvage plants showing signs of root rot by removing them from their wet soil and cutting off all affected roots with sterile scissors. Repot into fresh potting mix with additional perlite to increase drainage. Return to your normal watering regime after new growth appears.
Read the full article: Perlite vs Vermiculite: Ultimate Comparison Guide
