Rockwool Seed Germination Problem...Help

Hi there everyone,

first of all, I'm a new member long time reader of this forum and honored to be a member.

secondly,

im having a problem with my (sensi) northern lights seed germination in rockwool.

i did the moist tissue method and the seed poped with a small root.

I placed the root in a moist rockwool cube placed in an RO water ph 5.8 for 2 minutes prior placing the seed in the cube.

tody is the 5th day since I placed the sprouted seed in the rockwool which I kept in a dome under a heat mat above them are 2 Marse Hydro Ts2000w .

I spray them daily or semi daily with a mixture of Cal mag,advanced nutrients Micro Grow, and Voodo juice total ppm 157 .
Ph 5.8

how long should I need to wait until it comes out of the rockwool I'm starting to worry as this is my first DWC experiment.
I usually go with CoCo medium.

thank you,,

Good chance it was kept too wet, you need to feel a dry cube and a soaked cube, wrist flick a soaked cube until the water stops coming out, that’s about as wet as you want it. No need for nutes, just ph water for awhile. One or two sprays with a bottle is enough. Make sure not to crush the rock wool either. I usually take a little chuck of rock wool and set it on the seed hole.

No need for the nutrients at this early of the stage. You need to let them sprout ad develop at least its first true leaves. Also the post above is correct as well.

Thank you so much for the quick reply.

so I'm stopping the nutrients,how long till the leafs come up?

grower error might have burnt it already. You tell us, it's in front of you!

I place a seed in prepared rockwool on a heat mat under a light at 80% humidity 80 degrees and it takes from 6 hrs (once) to 3 days for it to brake the surface.

Noted.
Thanks.

it's my first time germinating in rockwool.

BIG_KAHUNA said:

Noted.
Thanks.

it's my first time germinating in rockwool.

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try rapid rooters or similar. they are much more forgiving IMO

BIG_KAHUNA said:

Noted.
Thanks.

it's my first time germinating in rockwool.

Click to expand...

You didn't germinate in rockwool you germinated it in a paper towel. Then you handled it to put it in your Rockwool cube. One way to kill a seedling is bacterial infection from your hands. I'd try starting another seed in the Rockwool cube yourself. I'd follow @J232 's instructions.

curious2garden said:

You didn't germinate in rockwool you germinated it in a paper towel. Then you handled it to put it in your Rockwool cube. One way to kill a seedling is bacterial infection from your hands. I'd try starting another seed in the Rockwool cube yourself. I'd follow @J232 's instructions.

Click to expand...

Will do that definitely now.
Thank you everyone.

I germinate always on tissue then transfer to rockwool.

Tissue until the seed tail shows.

Run rockwool under tap until it's all wet.

Tease open existing hole in top of cube.

Drop seedling in with tweezers, tail down, or ar least sideways.

GENTLY / LOOSELY tease rockwool over top of hole covering seedling.

Place in warm cupboard or under light.

They pop in around 24 hours to 48 hours. Rarely more than 3 days max. Usually most are through within 24 hours.

The reason I "gently" cover them is so they break through quickly and easily so I know all is well.

Keep the cube, "not dry". i.e. moist but not soaked. Check it each day - compare to a dry cube in terms of weight. If drying out, briefly dip in water.

Your aim is to never let the cube dry out completely, but let it dry out somewhat between watering.

They are incredibly reliable once you get used to their weight and watering regime.

Be warned, as much as they can hold a lot of water, they can also dry out incredibly quickly.

p..s no nutes! Their shell contains all the nutes they need for a while.

I nearly choked when I read "I spray them daily or semi daily with a mixture of Cal mag,advanced nutrients Micro Grow, and Voodo juice total ppm 157 Ph 5.8 " " ! - all that stuff! They need none of it!. They germinate just fine in mud....

p.p.s I guess I'm lucky with my water (naturally around 6) so I never had to "PH" it (I do PH correct my grow tank!)

Did you cover the hole after placing the seed into the rockwool? Are you sure the taproot was facing down? After this many days, I have a feeling the grim reaper visited your seedling but I'll cross my fingers for you.

I also agree that you don't need nutrients when sprouting a seedling but anecdotally I think I get better starts soaking my cubes with a very low concentration of nutrients (1/4 strength maxi gro). You definitely don't need cal mag though - you can probably throw your cal mag in the trash tbh.

Tease them open from the top to check. It's easy with tweezers. Likely they are white and furry (mould) or nute burnt and dead. Either way, too much of everything. They are amazingly resilient little buggers as long as you don't let them dry out (even then, I've rescued teh odd one)

So I did a lot of trials with seed germination and I will tell you what works and what does work when using rockwool. I have never germinated in rockwool directly so keep that in mind. But I do insert the seed into rockwool after the seed cracks open.

First here is where you went wrong, you ph'ed the water that you soaked the cube to 5.8. I've done this many times, and it killed my seeds every time. There is zero reason to ph the cube at all. Adding nutrients probably did not help too much either, however I did not do any testing germinating with trace amounts of nutrients.

I place seed(s) in a shot glass (filled with RO water) and cover it with a ceramic coffee mug on a hot plate set at 24C. I'm aware an image is probably needed for this.

After 4 hours, I remove the mug and tap the seeds to have them drop to the bottom, and place the mug back over the shot glass.

After ~18 hours total (including the 4 hours before tapping the seeds) the seeds will crack, it maybe very hard to see sometimes so waiting 24 hours has always seemed to work as well.

Now preparing the cube. Easy, dunk the cube in RO water non ph'ed! Don't worry about the ph and there is no magic time for how long to soak a cube, just soak it for a minute, doesn't matter.

Now I do like to preheat the cube to tent temperature, but I've had success even with cold cubes as the heat up quick on a heat mat that is under a germination dome. I keep the dome dark since rockwool seems to have a light yellow look, I feel that light maybe easy to enter.

EXTRA: I have done test with a documented spreadsheet and have basically grown a seedling with purely RO water up to 11 days before showing deficiency's. 7 days appears to be real safe to go without nutrients.

I hope this helps someone because I spent a lot of time and money figuring this out. I'm still a noobie, but I believe I am an expert level seed starter lol.

Ive always had trouble with rockwell being too wet, l like rapidrooters or peat plugs. Way better percentage live. Unfertilized final medium works best imo, l soak it once and let them go, everything is up and no need to water for some time if using 1 or 2gal pots. I like to let tap root go as deep as l can before its disturbed. Roots grow best when dry, ample o2 and youll get healthy plants leaves will fall if underwatered, watch close and water when they need it. It doesnt need to drop just droop a little. Killed them overwatering but never underwatered one.

Soak cube in RO/distilled water at 5.5 PH for a few minutes

Put seed in cube, press it down ever so softly into the rockwool with a tipped instrument (think dab tool or tooth pick)

Fill hole loosely with rockwool

Let sit under your light at the recommended height

And remember, If its too hot or humid for you, then its too hot and humid for your seedling.

Use the weight of the cube to see if the plant needs watering. 10-20% is as low as you want it to get, at which point you can dip the lower third pf the cube into water prepared as mentioned above, I wouldnt let it sit for more than 2 seconds.

I'm new at this, but I have had 100% Success germinating with this method across 12 plants in rockwool