Why clean and what you need
The poster says used coco can hold salt buildup, root debris, dead microbes and pathogens, so cleaning helps restore a balanced stable medium and saves money.
Tools listed: large buckets, clean water, 3 percent hydrogen peroxide, measuring cup, optional pH meter and gloves.
Bucket cleaning method
Break it up
remove large roots, plant matter and debris, and break up hard clumps
Pre-rinse
place coco in a bucket and rinse thoroughly with clean water while agitating
Soak
add 3 percent hydrogen peroxide at 1 cup per 5 gallons of water, stir and soak for 30 minutes
Agitate
stir or mix well to release salt buildup and break down organics
Rinse thoroughly
rinse 2 to 3 times until water runs clear and no foam appears
Check pH and EC
the poster targets runoff pH around 5.8 to 6.2 and EC below 0.5 mS/cm; if high, repeat the rinse
Targets before reuse
Ideal coco pH range on the poster: 5.8 to 6.2.
EC target: 0.3 to 0.6 mS/cm.
PPM target: 150 to 300 PPM.
Recharge before reuse
Rehydrate with pH-adjusted water in the 5.8 to 6.2 range.
Optional recharge
add beneficial microbes or a coco-specific product and let it sit for 12 to 24 hours
Feed lightly with quarter to half strength nutrients to reintroduce calcium, magnesium and trace elements.
Soak and rest for 15 to 30 minutes, then drain excess water before planting.
The poster warns not to let the medium dry out completely after recharging.
Alternative sink flush method and storage
Alternative method
put up to 5 gallons of used coco into a 7-gallon fabric pot set in a sink or tub, then rinse and agitate while it drains
Use a plant stand or riser with holes under the pot to improve drainage and flushing speed.
Store cleaned medium in a sealed breathable container or bag, keep it cool and dry, and use within 2 to 4 weeks for best results.
The poster notes that reused coco previously fed with slow-release products may continue releasing nutrients and can run too hot for young plants.