rock wool

CAPCOM · Dec 23, 2015

Anyone using rock wool for seed starts this year and/or in the past. What's the low down good and bad. Looking for a formed cell material but don't want root riot.

queequeg152 · Dec 23, 2015

i prefer the peat sponge pods.

rock wool seems to hold either too much water or too little... its difficult to tell just from looking as well.

that being said, the germination rate for my tobacco plants was like 95% in rockwool. i dont recall what the rate was for peppers. peat sponges might be slightly better, but mostly i like them because they are easier to keep watered.

CAPCOM · Dec 23, 2015

Do these peat sponges have a name?

queequeg152 · Dec 23, 2015

not one that i can recall.

queequeg152 · Dec 23, 2015

root riots... thats what they are called.

i used to get em at the local hydro store.

Streetspirit · Dec 23, 2015

queequeg152 said:
root riots... thats what they are called.

i used to get em at the local hydro store.

I use them too

Peter S · Dec 23, 2015

I've been experimenting, on a very small scale, with both rock wool and Rapid Rooter sponges. I didn't germinate seeds in either, I used paper towel/sandwich bag method. Once tap roots came out I transferred to one of the growing mediums. Side by side, the sprouts seem to do better initially in the Rapid Rooter plugs, but after starting on nutes, it doesn't seem to matter between the two. Rock wool is significantly cheaper, if you shop around. Here are two, both came of out a dwc setup, and were transferred to potting mix.

This is a Caramel Moruga Scorpion in a Rapid Rooter plug.

This is a Jamaican Hot Chocolate in Rock Wool. I think it's about a week behind the Moruga.

After transplant.

Here's some kale in rockwool, in ghetto Kratky setup.

Some misc peppers in rock wool.

Some in Rapid Rooters.

Both seem to dry out equally as fast. I have kept water in the very bottom, enough to keep them moist and haven't seen any problems.

I know it's very limited data, and not scientific, but hope it's helpful. I lean toward liking the Rapid Rooters better, but the rock wool is much cheaper. I plan to keep buying both, but keeping the rock wool more for backup, at this point. I might change my mind later after using them more.

willard3 · Dec 23, 2015

I use rock wool to germinate occasionally. I like rock wool because it has no other ingredients and it holds the right amount of water.

dragonsfire · Dec 23, 2015

Was interested in this myself, have not found any supplies here yet, still looking.

http://grodan101.com/knowledge-center/rockwool-growing-substrate-hydroponic-systems

parker49 · Dec 23, 2015

queequeg152 said:
root riots... thats what they are called.

i used to get em at the local hydro store.

Will the root riots stand up well on there on own. And what i mean is i have standard 1020 trays without individual cups within it, so i just put them in there do they fall over or will they remain up right? Can you put more than one seed in them? I have just used peat pellets in the past, and they have worked okay but this might be a good alternative.

CAPCOM · Dec 23, 2015

I appreciate the feed back. I have used the rapid rooter before. There were thing about them I didn't care for and there were areas they excelled. I have been leaning toward rock wool because they are not treated with anything. The rapid rooter on the other hand do have something impregnated into the plug that caused in my opinion a high percentage of mutations in last years grow

parker49 said:
Will the root riots stand up well on there on own. And what i mean is i have standard 1020 trays without individual cups within it, so i just put them in there do they fall over or will they remain up right? Can you put more than one seed in them? I have just used peat pellets in the past, and they have worked okay but this might be a good alternative.

No, they are narrow at the base. If you flipped them upside down and cut a new slit , it might work nicely.

parker49 · Dec 23, 2015

CAPCOM said:
I appreciate the feed back. I have used the rapid rooter before. There were thing about them I didn't care for and there were areas they excelled. I have been leaning toward rock wool because they are not treated with anything. The rapid rooter on the other hand do have something impregnated into the plug that caused in my opinion a high percentage of mutations in last years grow

No, they are narrow at the base. If you flipped them upside down and cut a new slit , it might work nicely.

ok thanks, good to know. I hadn't even considered trying them until this thread.

R1dreamer · Dec 23, 2015

Never tried rockwool but I can tell you that grow plugs are leaps and bounds ahead of the old "pucks". Not only germination rate but time required. Grow plugs in my incubator at 85 and 70 percent humidity, we're talking basically 100 germination rate or pretty close.

I should mention seeds were started at the same time in the top pic.

CAPCOM · Dec 23, 2015

R1dreamer said:
Never tried rockwool but I can tell you that grow plugs are leaps and bounds ahead of the old "pucks". Not only germination rate but time required. Grow plugs in my incubator at 85 and 70 percent humidity, we're talking basically 100 germination rate or pretty close.

I should mention seeds were started at the same time in the top pic.

I used the compressed plugs for years and moved on to the root riot. Now I will be using rock wool. Just picked up 2 flats of 98 squares.

mrgrowguy · Dec 24, 2015

I used to rock the wool, but now I just paper towel germ and transfer to seedling mix in a small pot. The rock wool was unnecessary work for me. But it worked just fine, results-wise.

...

CAPCOM · Dec 30, 2015

mrgrowguy said:
I used to rock the wool, but now I just paper towel germ and transfer to seedling mix in a small pot. The rock wool was unnecessary work for me. But it worked just fine, results-wise.

...

Yeah, I can imagine me using the paper towel method last year. 365 damp paper towels laying around the grow room.

I like having a preformed media to start with. It's keeping it economical and beneficial at the same time that is the ticket.

santis00 · Dec 30, 2015

That root riot looks pretty cool. in the paper towel germination phase right now, if i get more seeds for different varieties may have to pick up some of these bad boys.

CAPCOM · Jan 1, 2016

Well, I started my rock wool start on the 26th and no hooks yet. The perforations in the rock wool are somewhat deep and could account for the hooks delayed presence.

Chilidude · Jan 5, 2016

I always start my plants in the rockwool cubes and put the cubes in a bigger pot once the small plants starts to grow roots.

CAPCOM · Jan 10, 2016

Finally getting hooks. Did an overlap sowing just in case 1st seeds were a bust. Rockwood is a whole different animal from what I am used to. Difficult to determine just how much moisture content is there.