Tropicals & Tender Perennials: seedlings, 0 by Kell

Kell wrote:
I love rockwool, Judy. I use the small blocks. Grodan Multiblocks 1.4x1.4x1.5 Sheet of 98. It usually is under $10.00. I put maybe 3 seeds per little square.

Let me first say, I do no care what anyone uses. I hate to do a hard sell on this. I know others have great luck using soil or perlite or what ever. This just happens to work best for me, I really like it. I have read where others hate it. I think people should experiment till they find what works best for them.

I do not believe it is a health risk at all. But if you are more comfortable using a mask or not using rockwool, that is your decision!

I have read lots and lots about it. There are a few websites that say you need to wear a mask but if you research it, that is not true. Even people who work with it 8 hours a day does not have to wear masks unless it is flying all over. It is classified as an irritant not a carcinogen. Even if you breath it in, your body will get rid of it. I read that some people are allergic to it and will rash. Others itch from it. I have never had a problem but I only have it in my hands for about 10 seconds.

It has been used extensively as a thermal & building insulation material for many years. In 1969 Grodan, http://www.grodan.com/sw55201.asp
the best known manufacturer started making it as a substrate for plants. It is made from spun volcanic rock. It is ideal for it holds so much water yet still is full of air so it is ideal for growing roots. Also it is disease free!!

Here is the Material Safety Data Sheet on rockwool:

http://www.rockwool.co.uk/graphics/RW-GB-implementation/data...

With that being said, I am also very careful with it. I am not into tempting fate. But it is not a crumbly material. It is a tightly spun together. I do not see a lot of stray fibers with it. It isn't dusty like perlite is.

I wet it down immediately which keep the fibers from getting airborne if there are any that want to. I also would not hold it over my face when I break it apart. But it has been used for many years now in building and no one is dying or even ill from it. It is used all over the world.
Europe produces over 50% of all their greenhouse grown vegetables using it.
http://europa.eu.int/comm/environment/ozone/conference/lisbo...

I love it because it is so fast, so easy, so clean, and the seeds need little follow up. And most of all because I get great germination.

My procedure is so fast and easy!

I only use clean or new things. I wash my hands well. I break off a piece of the rockwool cubes depending on the number of seeds I have to plant. I place the rockwool into a Tupperware type container. I take to the sink and run warm water over it for about 10 seconds, I turn it over and drain it out. This all takes about 10 seconds. I place on counter, and usually make more holes with a pencil so I can add more seeds.

I place seeds in holes and just gently press them so still on top. I take clear plastic bag, wet the inside, shake it out and place the Tupperware like container in it. I then close it with a Velcro tie and place it under my lights. This entire process might take 1 minute.

I do NOT open the bag again till the seedlings are about 4 inches high. There is no need to water them again. NO FUSSING over them!!

When big enough, I gently separate them. I also tear off any excess rockwool. I then plant them their own pot with soil. I bury the rockwool under the dirt.

I know all the sites say you must use a conditioner to adjust the PH of the rockwool before use. I have NEVER used a conditioner and my plant growth is just great. I use plain water.