How do you get sprouts into rock wool cubes to be used in hydroponic system


A customer has a question and I hope we can get some opinions on it, thanks

How do you get sprouts into rock wool cubes to be used in hydroponic system


Your supposed to put the seed in rockwool so it sprouts in it. If you sprouted in peat pellet or plug just leave it in that. Otherwise you could gently wash soil off roots and use hydroton to support seedling. If you sprouted in paper towel just drop it in rockwool seed side up. You may need to make hole in rockwool bigger.


Rockwool is one of the harder mediums to start your seedlings in IMHO.

@TDubWilly uses rockwool and hydro. He can help you out.

I am also a hydro grower, but I use rapid rooters for my seedlings. In my case, I sprout the seed (usually just 24 hours in a shot glass with water and a couple drops of H2O2) then put them into my rooters. I have to slice the rooter open vertically so I can put the sprouted seed in.


join our forum,there are plenty of folks that are happy to help…
best to start seed in rockwool…


I germinated(paper towel method) my seeds for 3 days first then put them in Rockwool. I put the taproot into the little hole and left the seed casing exposed at the very top and kind of pushed the Rockwool, with a toothpick, to cover the taproot so it got zero light. 10 out of 10 seeds popped. Only 1 didn’t make it.


why would you want to put sprouts into rock wool
Did yoo start them in hydro and now want to go to a soil grow
Please join us so we can help guide you to a successful harvest


I have a hydro set up but 2 days into germination had to move my set up. Couldn’t do hydro(closet isn’t designed to for my bucket system) where I had to move it so ended up in soil at last minute. Plus it just seemed easier to germinate the seeds then put in Rockwool and all had popped in 4 days.


I sprouted my seeds in paper towels, then take a SOAKED rockwool cube, make the hole a little bigger and insert it. Then I push the rockwool around the opening to cover it. At this point I put it in my humidity dome for one week with a 125w cfl light on it. After that I put it in my netpot with hydroton and put it in the bucket. Then, I let the good times roll. It’s always best, right after you do all that, to smoke a big fat one.


Once the seed germinates and the tap root is exposed i will move to Rockwooll or rapid rooters. I think i like rapid rooters a little better but have success with both.

As far as moving them to either rapid rooters or rockwool, after breaking many a tap root, i started neatly tearing cubes or rooters in half heightways, then i could simply place the seed and tap root in the shaft of one of the torn sides, then took the other side of the rockwool/rapid rooter and put it back on like i never tore it off.

The fact that its wet, and surrounded by clay pebbles or some other growing medium holding decent pressure on at least 5 of the six sides makes it where it functions identically to a cube or rooter that was never torn in half.

If your like me you’ll forget about your seed germinating and have to contend with sticking a long and fragile tap root down that hole and breaking almost every one that is over half an inch.

As far as a transplanting a sprout with roots into Rockwooll, idk.


I germinate and place directly into soil
No need for plugs or rockwool in soil


Hello, after many failed attempts, probably 50% or so, I found a great method. Soak a paper towel with bottled water (cheap towels work best), squeeze out excess water so its moist, but not soaked and dripping. Fold in half. Put it on a saucer, place seeds on it (make sure to wash hands thoroughly before touching anything). Fold over the paper towel and press down gently so you can see the seeds as little bumps (no air pockets). Place another saucer on top (upside down so it looks like a flying saucer). Put into a warm place, think 80 degrees f. Keep checking on it every 12 hours or so, if the towels dry up(and they should at least once), add like 1 tablespoon of bottled water right onto the top of towel and put saucer back on top. Once the tap roots pop out about 1/2 to 1 cm, use tweezer to put into rockwool tap root down. Ok, for prep of rockwool I fill a small bowl with water and soak the cubes for 24 hours in bottled water. Then pull them out and let them sit for an hour or so to drain excess water out. (This pre-soak is to balance the ph levels better). Now, when I put the seed into it, I RIP it open to the middle, put seed in with tweezers very carefully. Then close it up, tear off a small piece off the side of rockwool and cover the opening at the top, gently, just cover it, don’t jam it in there. Then I put them in a seedling tray, and cover with a humidifier some. My seedling tray has a heat mat as well so I turn that on to 80 degrees f, or so. Once the seedling pushes up out of the rockwool, I add small cfl lights about 2 inches above the top of seedling, and keep the rockwool moist (not soaked). 100% success rate so far. Good luck!


…humidifier dome, not some.


I used rockwool cause I was going to hydro but at last minute ended up in soil.


I have some rockwool in soil too, no harm done.