In addition to the many excellent qualities of rockwool as a growing medium, one of its most important characteristics is its reusability. The fact that you can reuse rockwool for up to six different crops prevents waste and helps you save money. Give your plants every environmental factor they need to succeed, and keep these steps from this short guide to reusing rockwool in hydroponics in mind before you purchase replacement rockwool.
Preparing the Rockwool After a Successful Harvest
Unfortunately, reusing rockwool isn’t as simple as removing the old plant and placing the new plant in. Just as you needed to spend time preparing the rockwool initially, you’ll have to do similar preparations to reuse it. Your rockwool reusing procedure should go as follows:
Remove the Old Plant and All Plant Debris
Before you start your preparations, you must make room for your new crop. Take the old crop out of the rockwool and dispose of it however you wish. Once it’s out of the growing medium, gently scrape away any root debris left behind. If you damage the rockwool by scraping too forcefully, you may reduce its effectiveness and structure.
Do not remove the plastic wrap from the rockwool at this time; the wrap blocks sunlight and prevents algae. Instead, cut holes all around the wrap to encourage drainage.
Sanitize the Rockwool
Your next task is to sanitize the rockwool with a method that won’t damage it or harm future crops. There are a few different ways to sanitize rockwool after you’ve used it:
- Enzyme cleaning solution from a hydroponics supplies retailer
- Hydrogen peroxide wash
- Steam the rockwool for 30 minutes in an enclosure
Re-Stabilize the pH
Just as you stabilized the pH of the rockwool when you first got it, you must stabilize it again. After using rockwool, its pH may become altered and unsuitable for your next crop. Give it a pH stabilizing bath, as you did on day one to facilitate your plant’s growth.
Pick a Different Crop
With your rockwool properly sanitized and its pH rebalanced, it’s now time to place the new plant in its new home. Don’t grow the same crop as you did before. Much like farmers need to rotate their crops to maintain healthy fields, you must rotate yours as well. Avoid growing crops from the same botanical family in the old rockwool!
Additionally, don’t reuse rockwool that you’ve germinated seeds in.
How To Dispose of Rockwool
Sending rockwool to the landfill in one piece isn’t a good idea. Because it is inorganic, it will not decompose and will sit in the landfill for many years. Shredded rockwool, however, provides potting soil or compost with an extra boost of oxygen that goes directly to a potted or outdoor plant’s roots. Make sure to wear gloves, a facemask, and goggles when handling or shredding dangerous rockwool strands.
If this guide to reusing rockwool in hydroponics convinced you to start using it in your hydroponic garden, let FloraFlex supply you with our ready-to-use rockwool grow cubes today!