Can vermiculite and perlite be reused?
Written by
Tina Carter
Reviewed by
Prof. Martin Thorne, Ph.D.Using vermiculite and perlite again maximizes their benefit and lowers gardening costs. Both products are sterilized and reused multiple times, as they can be cleaned and reused without any loss of efficacy. For several years, I have been reusing my amendments using the protocols presented here. Sustainable gardening goals become easier if you can save money and reduce environmental impact with your options.
Preparation
- Remove plant roots and debris thoroughly
- Rinse materials to remove soil particles
- Spread in thin layer on baking trays
Sterilization Methods
- Oven method: 200°F (93°C) for 30 minutes
- Solarization: Seal in clear bags in direct sun for 2 days
- Steam treatment: 15 minutes in pressure cooker
Oven sterilization continues to be the best way to reuse growing media. Baking at 200°F (93°C) will kill the pathogens and provide no damage to materials. I process large batches four times a year for my nursery. Be careful to monitor your temperature to avoid overheating and damaging the amendments in your media.
Amendment durability varies. When handled properly, perlite can last forever. Vermiculite will disintegrate after 5-7 cycles and will no longer be effective. I keep track of my reuse cycles in the storage container. I would replace vermiculite once you can tell that its water retention is getting significantly worse.
Safety precautions are important to protect your health while processing. Be sure to maintain as much airflow as possible when handling any dry materials. When sterilizing materials, wear N95 masks and gloves to protect yourself from potential hazards. I learned the hard way that this prevents respiratory irritation. It is also good practice to dampen materials before handling to limit the likelihood of airborne dust particles.
Quality checks will ensure that reused materials perform effectively, screen materials for root fragments before sterilization. Use a small sample to observe water retention. I check each batch of reused material before using it in new mixes. Dispose of any materials with mold or strange odors right away.
Environmental benefits make reuse worthwhile. Recycling amendments greatly diminish mining demands. It minimizes the carbon footprint from production and transportation. My garden operates sustainably via its systematic reuse programs. Your plants enjoy while you maximize resources.
Read the full article: Vermiculite vs Perlite: Ultimate Comparison
