Freshness of Potting Mix.
 

So. I was cleaning out my orchid supply area. I keep my potting mixes inside a large plastic tub, which was supposedly airtight. I noticed that the clear bags in which the orchid mixes come in were humid. I opened some and they smelled musty.

I decided to throw them away 1) because I wasn't sure they were "good" and 2) I'm not planning on buying any more orchids of that type.

which, leads me to the question.....if you don't use a particular orchid mix immediately, how long do you keep it? How long are they good for? I'm sure the ingredients degrade or start to at some point, but how to determine that? I know lava rock lasts forever, but what about other ingredients?

I erred in the side of caution, and well, like I said before, I'm not going to buy any more orchids of that type, but I'm curious as to what everyone thinks.

It depends, if it's sphagnum or coconut husk chips (CHC) and it smells musty and is moist I will dump it. Whereas bark is no big deal to me.

If I catch it happening with bark though, I will dry it out in the sun for a few days and then re-store it.

Weebi,

I will have to disagree with you on the bark. The biggest source of problems I have found on bark is snow mould. :_( Speaking from 50 years of experience, once that happens usually due to moistness in the bag, no amount of drying or even using anti fungal or anti bacterial solutions will stop its reemergence if it is used. :( Sadly, our best supplies of bark on the west coast are fast disappearing and the products now available are not treated the same as the ones we once got. Coir and CH are fast becoming the media of choice but keeping them dry but not in air tight containers prior to use, seems to be the key to longevity.

CL

I use straight bark for potting, and since I never use all of it at once I spread it out on the ground to dry. Once it's dry I bag it again and put in 2-3 of those silica packets you get in shoeboxes to attract any remaining moisture. I don't know if they really help at all, but I figured, why not?

I keep bark in plastic drums up to 6 months or more after I have soaked it for a week or so, this also removes the tannin in the bark, I also put about a tablespoon of lime in when soaking,then I drain it and for a day in the sun which partly dries it and seal it in 10ltr buckets,seems ok with no mould.