I planted about 20 different plants in containers.
I used vermiculite that had set outside for few years and had gotten wet ...
I researched if vermiculite went bad and I believe it said it wouldn't! Unfortunately I no longer believe this as none of my pots will dry. I have used the same soil mixture for over 5 years with good results. Just soil, composting material like eggs , coffee, things from my home and vermiculite..
In the past I've had a few pots give me a hard time drying out but this is every pot is staying wet .. way too wet. A few plants are starting to suffer now. .
Anyone have any ideas besides repotting everyone!?!!!

Here's a discussion which you may find informative
The thread "Vermiculite, perlite, or pumice?" in Houseplants forum

I can't stand that stuff, it retains too much water. I use perlite to improve drainage and aeration.

I've used vermiculite in my indoor houseplant potting mix for decades with beautiful results (1 part peat moss, 1 part perlite and 1 part vermiculite for general purpose, use 2 parts peat moss for plants that need to stay more moist), it has it place when used properly. Unless it got moldy or some contaminate got into it from overspray or runoff, it shouldn't go bad. I think it was a case of just using too much with already moisture retentive ingredients. And if outdoors in spring where it could rain a lot with young plants without root systems to use up all that extra moisture, that's definitely going to cause problems.

Duplicate thread

I would never, EVER use vermiculite. As stated above, all it does is hold water. That leads to root rot quickly. If used at all, it should be used as a mix in, in very minute proportions