How To Sterilize Soilless Growing Medium
To re-use growing medium for another crop it must be sterilized first to remove any destructive pests and diseases before it is able to be used.
Many times sterilizing is easier and more cost-effective than purchasing new growing mediums especially when using other types of soilless growing medium that is available such as gravel, expanded clay, and mica.
Be sure to avoid sterilizing and reusing soilless growing medium that compacts so it loses structure, such as Rockwool, coconut coir, perlite, vermiculite and peat moss.
These growing mediums should be replaced after every use. Before sterilizing your growing medium it is best to remove roots from the growing medium and some growers will rinse the medium then dry out the media before sterilizing it.
Re-Using Your Cannabis Growing Medium
This makes it easier to remove dried out small root particles and allows fertilizers to dry out so it is easily washed out the second time. Many growers will use mesh-wire screens to help in removing dried out roots, this is done by placing some media onto the screen then shaking and bouncing it around.
This beats the growing medium against the screen which allows the dried roots to fall through the screen that falls off the used/dirty growing media. Many growers use enough growing medium to keep a grow cycle for their garden some used for vegetative growth, part for flowering and then the rest for the rinsing/cleaning cycle.
Having three (3) stages that you’re using growing medium makes the growing process less-rushed for the next cycle that needs to be planted and transplanted. Plants and growing mediums that have fewer decaying roots cause fewer pests and disease problems.
It is important to always keep healthy plants with proper growing practices to prevent decaying roots and pest problems. Washing growing medium in a large container such as a bathtub or larger bucket works best when cleaning and washing.
One thing that you will want to be sure is that no root or media goes down the drain since it can easily clog up the drainage. This works well with expanded clay or mica.
Once roots are removed from the growing media you will want to soak it in a sterilizing solution for at least an hour. Many people use five percent laundry bleach (calcium or sodium hypochlorite) or hydrochloric acid (used for hot tubs and swimming pools).
Sterilizing Your Cannabis Growing Medium
When using these sterilizing solution, pour the solution out and wash the media thoroughly since it may take several rinses to get all of the agents out of the media. Remember that it is NOT recommended re-using Rockwool OR coco since you may have problems with pests and diseases.
If you do mix these mediums then be sure to mix with fresh/new growing medium, which is not as compact or deteriorated. A way to sterilize Rockwool is to ‘Solarize’ it by setting it outside to dry and covering them with black plastic.
By letting it sit for several days to make it reach 140° F (60° C) and this allows the sun bake slabs to kill off pests and diseases. When sterilizing a hydroponic garden media be sure to remove nutrients from reservoir and flood growing medium with a sterilizing solution for a one-half hour.
Make sure all residues are gone by flushing entire system twice (2x) for half an hour (30 minutes) then remove all solution from the system and scrub entire growing medium that has any signs of salt buildup.
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