From

Location

Message

Date Posted

Danville, CA (petman2@yahoo.com)

Seems people use just about everything from small peat pots to coffee cans to ..... to start their seeds in. Why not use Rockwool and then just cut the plastic wrapper off and plant the whole thing. The great thing about that is you can then water it with fertilizer and the rockwool will drain very quickly and provide air and very rapid root growth. I have used very small cubes to start cucumbers and squash with very good results. Not sure why I didn't think of it for my pumpkins. No transplant shock or root disturbance or .....

Any downside or ill effects anyone is aware of?

Searched the forum and found very very little, maybe there is good reason.

6/13/2006 1:53:24 AM

Knopp, Germany

I had to google this one because at the first glance I liked the idea. This is what I found:

Advantages of Rockwool
RETAINS WATER - Rockwool holds an incredible amount of water which gives you a "buffer" against power outages and pump (or timer) failure.
HOLDS AIR - Rockwool holds at least 18 % air at all times (unless it is sitting directly in water), which supplies the root zone with plenty of oxygen. This means that it is practically impossible to over-water rockwool.
COMES IN A VARIETY OF SIZES AND SHAPES - From 1" cubes designed for use in propagation, to 3"x12"x36" slabs capable of holding the root systems of huge plants, rockwool comes in dozens of shapes and sizes making it a versatile growing medium. Rockwool also comes "Loose" so you can fill pots or containers of any size.
CLEAN AND CONVENIENT - Rockwool holds together very well so it can't spill. Rockwool also comes wrapped in plastic, which makes it easy to handle and keeps evaporation to a minimum.


Disadvantages to Rockwool
NOT ENVIRONMENTALLY FRIENDLY - Rockwool is hard to dispose of, if buried it will last indefinitely.
DUST AND FIBERS ARE A HEALTH RISK - The fibers and dust from the rockwool are bad for your lungs. Wear a dust mask when handling to prevent problems.
pH PROBLEMS - Rockwool has a high pH which means you have to adjust your nutrient solution low so that the root zone is neutral. Rockwool is also susceptible to pH shifts meaning a bit more routine maintenance to keep the pH levels correct.
LONG PRE-SOAK PERIOD - Rockwool must be pre-soaked for 24 hours before use. Most other growing medium only needs to be well watered.

I am not sure that the advantages are more important then the disadvantages.

6/13/2006 3:39:44 AM

ENGLAND

http://www.grodan.com/sw12122.asp

6/13/2006 5:57:43 AM

Ctpumpkin@optonline.net

Vermiculite has been known to cause significant health problems to those who breath it in an occupational setting. I think the Canadian Peat Moss Association has been one of the loudest Rockwool critics. Imagine that? LOL

I think Rockwool could have some distinct advantages in some situations. It's very easy to sterilize, completely inert & drains very well. The cubs are also very easy to handle so root systems aren't likely to suffer during transplanting.

Since a cube would be fairly small, it can be discarded along with the stump when the plants are torn up at season's end. The impact on the soild wasted disposal situation would be no wrose than throwing away the plastic potting soil bags we use now.

On the down side is the possibility of restriction to the basal crown as these monsters grow. I'd try tearing a cube apart first using 2 pinky fingers. If it didn't tear easily, then I'd be very concerned.

6/13/2006 9:12:12 AM

Indiana

Good idea i think Rockwool is very similar to pink insulation and shouldnt cause any restriction problems at all.

Steve

6/13/2006 12:26:26 PM

Danville, CA (petman2@yahoo.com)

Rockwool is very similar to "pink insulation". It is like planting in air and it pulls apart with the greatest of ease. I actually hadn't thought of disposal, but rather thought I would just till it under like a peat pot. I like it being sterile and also holding lots of water AND air. May try the 6x6x6 or 4x4x3 cubes next year. 3 inches seems a bit shallow but this is really only a starting medium and not meant to grow the plant for long. The hazards are also similar to "pink insulation" in that it is basically a spun glass kind of stuff so wouldn't want to breathe in large quantities.

I used rockwool to root some Daphne plants a while back. Worked very well for me. Seems I read everything there was to read, and then forgot my basic gardening skills and intuition when it came time to execute. Will let you know next year unless I get ambitious this year.

6/13/2006 1:33:27 PM

Ctpumpkin@optonline.net

I think it's importatnt to try new processes. Somehow the spobby has grown tremendously & it wasn't be NOT trying new ideas.

6/13/2006 6:46:15 PM