Rockwool turned to mush

I've never used rockwool before, and I tried searching for this problem. Last night I put 9 rockwool cubes in water to soak overnight. I woke up this morning and the rockwool had basicly dessolved into a mushy slimmy substance. Does anyone know why this would happen?

My only guess would be if it somehow came unwoven or broken as a cube. But even then I'd just think it'd be as if you ripped off a piece of slightly wet rockwool, I wouldn't think it would actually be any more slimy feeling than usual, which I wouldn't really call rockwool slimy lol.. But it definitely has a strange texture to it. Definitely mushy, too. They're meant to be handled with some sort of care, at least.

Possibly it was overhandled, broken up, and just didn't really show until after it had absorbed a lot of water, I'd guess.. Aside from that I really have no idea if it just happened overnight. That's weird haha.. I don't think they have an expiration date or anything lol, and I ordered the cheapest ones I could find too, so I wouldn't guess there's a huge difference in quality between them all either.

I only soak mine for about 30 minutes or so, usually while I'm washing out hydroton. I'd say just try one real quick and see if it retains it's shape. If not, you may just have gotten a funky ass batch of rockwool lol

Thanks for the info


That would totally piss me off. I have to drive over an hour just to get it. And I hate ordering it even more.


I looked at it again later and noticed that the water smelled like rotten eggs or sulfer real bad. My only guess is that the hydro ph cyrstals take longer to work (1st time using them) than the liquid, causing me to add more cyrstals, while getting a false ph reading; thus causing the ph to be really low.....but I could also be way off base since I've never used rockwool before.

Haha, well I've never had to balance my pH either, personally. We've got awesome water in my area luckily. So I can't really give an opinion there.. But yeah, funky rotten egg chemical filled water may have done it? lol.. If your water's really that bad, I hope you don't drink straight out the tap lmao.. As good of a guess as any imo, chemicals do some funky stuff sometimes I guess.. I honestly don't have a clue about that bit. I just dip my cubes in tap water, and sort of splash them around, rinsing all of the powdery funk off and letting the water just sorta flush it out, and I'm left with a slightly squishy cube that's good to go. It was as simple as that for me..

Good luck with it though. I wouldn't assume that they'd all be bad, at least. Unless they really were just made like shit, but if there's varying quality in rockwool cubes then I really lucked out, cause mine were as cheap as I could find like I said lol..

My home water isn't that bad, ph probably around 8. But the buffers are bad, so I end up having to add shit loads of ph down. So I simply collect the water from a dehumidifier, which is running all the time anyway.

Used it once.

Vermiculite works best in my set up.

I'll never use that rockwool again.

I usually hit a 90 to 95 % ratio from seedling then into the netpots.

takes time and patience but it can be done.