What are the uses of perlite in horticulture?

The 6 Core Functions of Perlite in Horticulture:  
1. Loose and Well-Ventilated  
The porous honeycomb structure ensures an air porosity of ≥30%, breaking the oxygen-deprived environment of clay or compacted substrates, allowing roots to breathe freely and reducing root rot.
2. Water Retention Without Waterlogging  
It can absorb 3–4 times its weight in water and drain excess water within 5 minutes, effectively preventing both drought and waterlogging.  
3. Reduced Bulk Density for Easy Handling  
Dry bulk density ranges from 50–120 kg/m³, approximately 1/15 that of garden soil, making it safe for use on rooftops, balconies, hanging pots, and vertical green walls.  
4. Inert and sterile, inhibiting pests and diseases  
After expansion at 1000°C, it forms glass-like inert particles that do not carry pathogens or insect eggs and do not react with fertilizers or pesticides, reducing the spread of diseases.
5. Thermal insulation  
Thermal conductivity of 0.04–0.06 W/(m·K), buffering daily temperature fluctuations to protect roots from freezing in winter and high temperatures in summer.
6. Promotes root development and nutrient management  
Pores can “store” nutrient solutions, which are slowly released via capillary action, increasing fertilizer utilization by 20–30%; roots penetrate easily, promoting well-developed root systems and healthier plants.