Rockwool cubes

[manicscousers]

anyone used these, thinking of using some instead of jiffy 7's. can I transplant these into compost when the plants are bigger. I know they are used in hydroponics, any advice greatly appreciated  ;D

[manicscousers]

[Nigel B]

Yes you can, is the short answer. :)
They make a very good rooting medium. 'Hydroponic-ers' usually give them a pre-soak in water with a Ph of around 6, if possible, but other plants may not be as fussy as some folks think they are.
Remember though, that there's no nutrients in rockwell cubes, so you'll need to provide a weak food-mix while they root out...
Then, as you say, straight into soil and away............

[tonybloke]

anyone used these, thinking of using some instead of jiffy 7's. can I transplant these into compost when the plants are bigger. I know they are used in hydroponics, any advice greatly appreciated  ;D

Hi Manics.
I used these as part of a propagation study when at college.
Rockwool vs Jiffy 7's

these actually came out better, there is a better air/water ratio in rockwool. just fully submerge then completely drain before use.
plants can be transplanted no problems.
we did have a couple of plants getting 'strangled' by the netting on the Jiffy 7's.

rgds, Tony

[Nigel B]

Hi Manics.
I used these as part of a propagation study when at college.
Rockwool vs Jiffy 7's

these actually came out better, there is a better air/water ratio in rockwool. just fully submerge then completely drain before use.
plants can be transplanted no problems.
we did have a couple of plants getting 'strangled' by the netting on the Jiffy 7's.

rgds, Tony

Hi Tony, Just out of interest, did you have any problems with any kind of stem-rot with the jiffy's? I seem to remember that, if you left cuttings in them for longer than necessary, they seemed quite prone to it whereas the rockwell cubes didn't suffer.... Again down to the water/air ratio I suspect.

[manicscousers]

Thank you, Nigel, I'll give them a go then,

Hi Manics.
I used these as part of a propagation study when at college.
Rockwool vs Jiffy 7's

these actually came out better, there is a better air/water ratio in rockwool. just fully submerge then completely drain before use.
plants can be transplanted no problems.
we did have a couple of plants getting 'strangled' by the netting on the Jiffy 7's.

rgds, Tony

thanks, Tony, we had a couple of plants when they were finished, quite big ones, they still had the netting tangled around the roots  :)

[Vinlander]

I've used rockwool offcuts to add drainage to a bag of used compost and it worked well, but that was for growing tomatoes - and few plants are less fussy than toms...

What sort of density are the rockwool cubes? Fluffy like laying insulation or more stiff and solid like the sheets used as insulating panels?

I've made no secret of my meanness - so you can see where I'm going here...

Cheers.

[hippydave]

1 thing to remember about rockwool is that it does not breakdown in soil when plants are transplanted. so needs removing and not digging in.

[manicscousers]

What sort of density are the rockwool cubes? Fluffy like laying insulation or more stiff and solid like the sheets used as insulating panels?
Cheers.

don't know how they're made yet, just looking, I'm a bit worried about them holding enough moisture for things to root into
didn't know that, hippydave,might need a re-think  :)

[Poppy Mole]

We used these when I worked on a chrysanthemum nursery many years ago, they were very soon discontinued because of all the extra work involved in removing them before the next crop.

[hippydave]

its made by spinning rock and sand into fibers and forming blocks. The process is similar to making candy floss.

[tonybloke]

there's a company who purchase them from big tomato growers, shred them, and add to compost mix. so what if they don't break down, neither does sand, nor stones, nor perlite, vermiculite, all are used in growing media

[tonybloke]

I've used rockwool offcuts to add drainage to a bag of used compost and it worked well, but that was for growing tomatoes - and few plants are less fussy than toms...

What sort of density are the rockwool cubes? Fluffy like laying insulation or more stiff and solid like the sheets used as insulating panels?

I've made no secret of my meanness - so you can see where I'm going here...

Cheers.

go into a garden centre and look! ( difficult to describe density of product)

[Vinlander]

there's a company who purchase them from big tomato growers, shred them, and add to compost mix. so what if they don't break down, neither does sand, nor stones, nor perlite, vermiculite, all are used in growing media

Absolutely, I have no qualms about it getting from my pots into the second-use compost bag and thence into my soil.

And what's more - ground-up rocks are highly regarded in organic growing circles as a way of obtaining trace elements in the same way that glacial grind makes the most fertile soils and alluvia.

Not to mention the fertility of volcanic soils.

The particles in these (very expensive) 'organic' ground rocks aren't that far from the dimensions of the fibres in rockwool.

Whatever mineral is used to make them, it is apparently harmless chemically (wikipedia), and you can pretty much guarantee that it is already in your soil (unless you are gardening on 100% humus).

It appears that the only risk from rockwool is the shape of the dust particles - they are tiny needles so can cause big problems in your lungs.

Unless your soil is very dusty there should be no problem having rockwool in there, and even if it is then it's no problem as long as it stays below the surface - so mulch!

The tiny needles can also irritate the skin - but not in 10s or 100s - unless they get inside your shirt...

Cheers.

[tonybloke]

What sort of density are the rockwool cubes? Fluffy like laying insulation or more stiff and solid like the sheets used as insulating panels?
Cheers.

don't know how they're made yet, just looking, I'm a bit worried about them holding enough moisture for things to root into
didn't know that, hippydave,might need a re-think  :)

no problem about them holding enough moisture for cuttings, manics.