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!

 


Reuse

  1. Cut up cubes and add it to sandy or clay soils to improve tilth.
  2. 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%.
  3. Reuse in planters.
  4. 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

  1. Scrape the rockwool with a serrated knife and then pick out the roots as they become loose.
  2. 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.
  3. Submerge the rockwool in the hydrogen peroxide and water solution for 24 hours.

Bake It

  1. Preheat oven to250 degrees Fahrenheit
  2. Scrape the rockwool with a serrated knife and then pick out the roots as they become loose.
  3. Spread rockwool cubes on a cookie sheet and bake until the internal temperature of the rockwool measures 180 degrees Farenheit for 30 minutes.

Bleach

  1. Scrape the rockwool with a serrated knife and then pick out the roots as they become loose.
  2. Fill a bucket with one part bleach and 9 parts water.
  3. Soak rockwool in the bleach for at least one hour.
  4. 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

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