Self-heating of vermiculite problem

[SkyKuba88]

If the effect is temporary, I wouldn't be overly concerned about it. You don't have to put critters in right away, do you?

that's right. I held off on letting the spiders in, but the fact that it was heating up just worried me

 

[Chlorogoth]

I'm new to these forums & tarantula keeping, but I've been a hardcore gardener for decades. This has happened to me a handful of times over the years with a new bag of vermiculite. Vermiculite is composed partly of iron, and this amount can vary. If circumstances arise that vermiculite has high iron content and oxygen exposure wasn't total before packaging, then when you open a bag the residual iron oxidizes and generates some heat. It's the same general principal behind chemical hand warmers. I learned this from a chemistry student when we were discussing non-organic soil additives, and I brought up that every now and then a bag of vermiculite is warm when I first open it.

 

[Introvertebrate]

I'm new to these forums & tarantula keeping, but I've been a hardcore gardener for decades. This has happened to me a handful of times over the years with a new bag of vermiculite. Vermiculite is composed partly of iron, and this amount can vary. If circumstances arise that vermiculite has high iron content and oxygen exposure wasn't total before packaging, then when you open a bag the residual iron oxidizes and generates some heat. It's the same general principal behind chemical hand warmers. I learned this from a chemistry student when we were discussing non-organic soil additives, and I brought up that every now and then a bag of vermiculite is warm when I first open it.

There we go. So, it's a one-shot deal? It only happens upon first exposure to oxygen?

 

[Chlorogoth]

There we go. So, it's a one-shot deal? It only happens upon first exposure to oxygen?

Yes. After the initial warming the vermiculite will cool to room temperature and will be non-reactive.

I want to give a disclaimer; if the vermiculite is moist and continues to produce heat then the source is most likely from microbial metabolic processes, and would require disinfection. I've never encountered this with a new bag of vermiculite, but I have experienced it with opened, improperly stored bags. A new bag that is dry, heats up once, and then returns to room temperature should be a one shot deal and safe to use.

 

[SkyKuba88]

Yes. After the initial warming the vermiculite will cool to room temperature and will be non-reactive.

I want to give a disclaimer; if the vermiculite is moist and continues to produce heat then the source is most likely from microbial metabolic processes, and would require disinfection. I've never encountered this with a new bag of vermiculite, but I have experienced it with opened, improperly stored bags. A new bag that is dry, heats up once, and then returns to room temperature should be a one shot deal and safe to use.

That's right! It's true that the entire bag doesn't heat up, only what's poured into the container. After the initial heating, which lasts a few minutes, the vermiculite cools down and nothing more happens. In spite of everything, today I received a package of vermiculite from a trusted source. When I have a moment later, I'll do some comparative tests In spite of everything, thank you!

 

[Chlorogoth]

That's right! It's true that the entire bag doesn't heat up, only what's poured into the container. After the initial heating, which lasts a few minutes, the vermiculite cools down and nothing more happens. In spite of everything, today I received a package of vermiculite from a trusted source. When I have a moment later, I'll do some comparative tests In spite of everything, thank you!

You are most welcome. I'm glad I could offer an explanation.