Wondering what to do with your used rockwool? Below you will find a number of ways to reuse or repurpose your rockwool after you have harvested your crops!
- Cut up cubes and add it to sandy or clay soils to improve tilth.
- Turn rockwool into granulate by running it through a woodchipper. Add some each time you throw stuff out for composting. It rockwool aerates the compost and speeds up composting by 20-30%.
- Reuse in planters.
- Use as “potting soil” for potted plants.
Sterilize and Reuse
If your seed failed to germinate or died off shortly after you can sterilize the rockwool in a number of ways. Choose which one suits you best. I know many of you will not want to use bleach but I wanted to share all the options available.
Hydrogen Peroxide
- Scrape the rockwool with a serrated knife and then pick out the roots as they become loose.
- Mix a solution of one part hydrogen peroxide with eight parts water in a bucket. The hydrogen peroxide will sterilize the rockwool and will break down into water after 24 hours.
- Submerge the rockwool in the hydrogen peroxide and water solution for 24 hours.
Bake It
- Preheat oven to250 degrees Fahrenheit
- Scrape the rockwool with a serrated knife and then pick out the roots as they become loose.
- Spread rockwool cubes on a cookie sheet and bake until the internal temperature of the rockwool measures 180 degrees Farenheit for 30 minutes.
Bleach
- Scrape the rockwool with a serrated knife and then pick out the roots as they become loose.
- Fill a bucket with one part bleach and 9 parts water.
- Soak rockwool in the bleach for at least one hour.
- Rinse the rockwool several times to remove all chlorine residue and then allow to air for 48 hours before reusing.
Places to Purchase Rockwool
Rockwool Alternatives
