Rockwool
The_herpetologist
West YorksPosts: 433
Sorry about the obscure question, but I just wondered whether anyone could tell me whether there's any reason why I shouldn't use rockwool in my garden. I have heard that it can act as a vertical growing medium for sedum and I would like to use it for this reason but not if it is going to have a negative impact on wildlife. My internet searches suggest that it can be harmful to people but there doesn't seem to be any information about possible impact on other animals.
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HH - I think Rockwool was used years ago on a commercial basis especially for Toms and similar. If you like, it was "early" hydroponics.
Don't know the full makeup but I'd think twice about using it in the garden as such. Early use kept it confined to glasshouse growing only - no idea what they did with it afterwards tho. As to it being harmful to people, there are many of us still alive who ate the produce from this form of growing medium.
You don't say but what are you thinking of using the rockwool for in an open garden situation ? Not being picky, just wondering ?
Thanks for the info. I have a large drystone wall and would like to make a feature of it by growing sedum in the cracks. Having done some research, it seems that even drought reststant sedum / stonecrop varieties need some moisture - especially early on. One message board I looked at had a comment from someone who said he had grown sedum on rockwol cubes and that they thrived. I was thinking of doing the same before transplanting the sedum into the cracks in the wall together with the rockwool medium which retains moisture very well. (Does that make sense?).
PS. I think I read that rockwool is only dangerous to people if inhaled (not as bad as asbestos, but similar principle) - although it is said that it is a skin irritant. One web site suggested using gloves and a mask when handling it which alarmed me as I have always just used my bare hands and handled it quite liberally.
An observation: if rockwool is used for house insulation would water retention be a good thing, or would it create damp issues?
If you had a leaky roof, I suspect the insulation would absorb a lot of the moisture, but equally would take time to dry out. Most attics are generally quite warm and dry so, unlike cellars, don't tend to see damp-related issues.
The rockwool cubes we use in horticulture are useful precisely because they absorb and retain water very well.
But they use it in cavity walls too. Are there different types?
Last edited: 14 August 2016 20:06:22
Could the sheepwool basket liners cut to fit the crevices etc. be used?
I'm afraid you have exhausted the parameters of my rockwool expertise Ladybird4.
Last edited: 14 August 2016 20:22:11
I'm not sure it would be dense enough to retain much moisture, but you have made me wonder whether sphagnum moss might be an option....
Thats a brilliant water absorber and retainer. Its why it was used during WW1 as a wound dressing. Nicer than rockwool!