Ph problem, an can I reuse?

A question from a fellow grower:

Just started a grow of ur Gold Leaf n have a ph problem! Water goes in at 6.5 but runoff measures@4.5 ! Growing in coco coir n perlite. Am reusing from first grow of white widow, can u do that? Do I need new coco coir? Any suggestions? Plants r turning yellow!

You can reuse coco and perlite, just like you can reuse soil-less media or even soil. You just need to flush it thoroughly, and I mean thoroughly, and then sterilize it before reuse. Did you do these things?

Either way a thorough flush with 6.5, or even 7.0 water until the pH coming out the bottom is a lot closer to 6.5-ish (5.8 - 6.2 is usually fine in coco), followed by a 6.5 pH, moderate strength, balanced nutrient mix sounds like your best hope.

Hope this helps,


Before re-using hydroponic medium, one should invest in a bottle of GH Flora kleen. This will dissolve and remove leftover slats from the medium and makes it safe to re-use. :slight_smile:

Just follow directions on the bottle and allow your used medium to soak overnight. I use warm water to start off with.