I am sifting all of last year's soil that I saved when repotting and about to start on the azalea soil, which had a lot of konuma. Does last year's konuma retain whatever it is that azaleas like? That would be after a year of heat, rain, and watering.

Would I want to mix more in? It was originally 1/3 konuma, so I could duplicate that amount, double it, or whatever.

I would asume it depends on the water used. The benefits of kanuma is that it is acidic. If lots of alkaline water is used that may not still be the case. If rainwater is used it is still ok and can be reused.

Easiest way to check is get yourself a cheap pH drip test for aquarium. Soak the kanuma for an hour. Test the water after. If pH is below 7 it can be reused for azalea. If not, use it in the mix for other species.

Tropfrog wrote:

I would asume it depends on the water used. The benefits of kanuma is that it is acidic. If lots of alkaline water is used that may not still be the case. If rainwater is used it is still ok and can be reused.

Easiest way to check is get yourself a cheap pH drip test for aquarium. Soak the kanuma for an hour. Test the water after. If pH is below 7 it can be reused for azalea. If not, use it in the mix for other species.

That is sensible. Our city water is treated to be close to 7.0, and rain water is close to that. We are not close to anything emitting much sulfur, which is the biggest acid rain component I know of.

I'll do it and see what happens.

Thanks.

The problem with Kanuma is it does break down quite quickly once it is wet, I have never been able to re use it again.

m5eaygeoff wrote:

The problem with Kanuma is it does break down quite quickly once it is wet, I have never been able to re use it again.

I took the azaleas out of the pot in a large plastic tub and there is a lot of Kanuma there about the same size as originally. I don't care much how big they are, just hiw acidic the soil winds up.

I'll take Tropfrog's advice and add new Kanuma as necessary.

Yes, it should be ok, to re use but it does disintegrate

The reused soil has yellow lumps and yellow powder, which sifts out, so the disintegrated soil won't be there. I think it will wind up mixing new Kanuma in. I need to find the ratio.

I might try that myself,

Ivan Mann wrote:

The reused soil has yellow lumps and yellow powder, which sifts out, so the disintegrated soil won't be there. I think it will wind up mixing new Kanuma in. I need to find the ratio.

Status of the effort:

Sifting the kunuma raises huge clouds of dust. After a short time my hands are yellow and my glasses are hazy. Soaking the pieces that don't fall through the sieve lowers pH from 7,5 to 6.8, so it might be worth it.