Should I avoid perlite because of fluoride toxicity problems?
While some perlite sources do contain fluoride, perlite is rarely the sole cause of toxicity problems because fluoride is quickly leached to safe levels. Chronic fluoride toxicity problems are almost always caused by persistent F sources like the water supply or contaminated fertilizer. If plant roots are continuously exposed to F levels more than 0.5 ppm fluoride, sensitive plants like lilies, dracaena, and spider plants are subject to damage. If fluoride toxicity is a problem, identify all F sources in the growing system. If the water contains too much F, all other fluoride sources including perlite should be eliminated. However, the mere presence of perlite will not trigger toxicity problems if there is no persistent fluoride source.
