Germinating in rockwool

[NamTran]

Does anyone has experience in germinating in rockwool? I tried it for the first time and all of my four seeds didn't germinated properly. it has been 12 days and nothing came out so I had to toss the whole batch.

What I did:

-Calibrate the rockwool cube in PH4.5 water with a bit of nutrients.
-Place the rockwool under a dome with a bit of water to prevent drying up
-Everything is under constant light to crank up the temperature a little bit.

Result:

Seeds germinated half-way
Sprouts turn mushy white but did not progress anyfurther.

 

[NuttyProfessor]

your ph and nutes would kill babies

 

[NuttyProfessor]

ph should be 5.5 , seedling dont need nutes they feed them selves first few weeks EDIT ( DAYS ) using the cotyledon leaves , are you putting into pebbles ? if not use these pots . cant go wrong , no transplant shock , they just break down

 

[Barney86]

Hiya buddy im a rockwooler. It takes a bit of getting used to and to be honest, root riots are better if you can get those.
What you need to do though is this.

Rinse them individually under water for a few minuits. Dont blast them so the cubes fall apart, just a nice solid stream. Once theyre rinsed get a bucket and fill it with enough water to cover them. Check the ph of the water then put the cubes in and leave them for an hour. If the ph stays the same then theyre clean. If not then repeat. Theyre riddled with some sort of alkaline that raises the ph like buggery if you dont get it out.
Once theyre clean give them another soak in ph5.5 nutes. Just like 50ppm root boost, 100ppm veg nutes. Any more than that and they can fry.
Give them a gentle squeeze to get the excess out then put the seeds in pointy side up at 10-15mm deep.
Any more and they tend to get stuck, any less and theyll come out with the shell still on. Same problems arise if its not pointy side up too.
Keep the cubes moist but not wet by using a spray bottle. Its a pain in the ass but the easiest way do get them just right.
Takes about 2 weeks for them to properly root up. Using a humidity box helps a lot, mine was only 99p from local garden shop and the difference is night and day.

 

[Barney86]

ph should be 5.5 , seedling dont need nutes they feed them selves first few weeks using the cotyledon leaves , are you putting into pebbles ? if not use these pots . cant go wrong , no transplant shock , they just break down

Few weeks from the cotys lol. Make your morning bowl a bit big this morning mate haha. Its about 5 days you get in rockwools, little nutes doesnt hurt but youre right its not neccesary till the coty turn yellow. Ive realised through trial and error that autos really dont like being made to feed from them though so ive stopped advising it. Had a few autos stunt on me from starting with zero nutes.
He is right though OP. They dont need nutes till the first wee leaves go yellow. Just saves having to watch for it. if you start with 100-150ppm you cant burn them anyway.

 

[NuttyProfessor]

yeah your right there mate .... , few weeks in soil or light fed coco .... ive never been into rockwool , hate it lol

 

[NamTran]

ph should be 5.5 , seedling dont need nutes they feed them selves first few weeks EDIT ( DAYS ) using the cotyledon leaves , are you putting into pebbles ? if not use these pots . cant go wrong , no transplant shock , they just break down

Hi, rockwool PH is topping at 8 so I tried to balance it out to 5.5 in 4.5 water, not really ph the cube to 4.5ph, haha. Sorry for the misunderstanding. I'm growing soilless with a root spraying system so I can't get any small particle in the nutrient tank. That's why I want to try rockwool. My first grow was fine but it clogged like crazy as I used a mixture of coir and soil as rooting substrate.

Hiya buddy im a rockwooler. It takes a bit of getting used to and to be honest, root riots are better if you can get those.
What you need to do though is this.

Rinse them individually under water for a few minuits. Dont blast them so the cubes fall apart, just a nice solid stream. Once theyre rinsed get a bucket and fill it with enough water to cover them. Check the ph of the water then put the cubes in and leave them for an hour. If the ph stays the same then theyre clean. If not then repeat. Theyre riddled with some sort of alkaline that raises the ph like buggery if you dont get it out.
Once theyre clean give them another soak in ph5.5 nutes. Just like 50ppm root boost, 100ppm veg nutes. Any more than that and they can fry.
Give them a gentle squeeze to get the excess out then put the seeds in pointy side up at 10-15mm deep.
Any more and they tend to get stuck, any less and theyll come out with the shell still on. Same problems arise if its not pointy side up too.
Keep the cubes moist but not wet by using a spray bottle. Its a pain in the ass but the easiest way do get them just right.
Takes about 2 weeks for them to properly root up. Using a humidity box helps a lot, mine was only 99p from local garden shop and the difference is night and day.

Thanks for the very detailed and useful instruction. Will it help if I germinate the seeds first in wet towels and transfer them to rockwool cubes later?
I think the problem with my case is too much water . I'll try again with moist instead of wet cubes.

 

[Barney86]

yeah your right there mate .... , few weeks in soil or light fed coco .... ive never been into rockwool , hate it lol

Yeah it took me a while to master using them. Had a few faliers along the way.
Im an NFT grower though so don't really have much of a choice. Just the way it is for us. Rockwools or nothing so had to figure them out.

 

[Barney86]

Hi, rockwool PH is topping at 8 so I tried to balance it out to 5.5 in 4.5 water, not really ph the cube to 4.5ph, haha. Sorry for the misunderstanding. I'm growing soilless with a root spraying system so I can't get any small particle in the nutrient tank. That's why I want to try rockwool. My first grow was fine but it clogged like crazy as I used a mixture of coir and soil as rooting substrate.


Thanks for the very detailed and useful instruction. Is it help if I germinate the seed first in wet towel and transfer seeds to rockwool cubes later?
I think the problem with my case is too much water . I'll try again with moist instead of wet cubes.

Nah you don't need to germ them first mate, just one more thing that can go wrong.
Here's my current lot ive been getting ready for NFT under a 130w CFL.
untill the roots look something like that you need to keep them moist but don't let them go dry or they'll knacker straight away.
Once the roots do look like something that you need to start feeding much more often or the salts build up and boil the cube. Im running 2l a day through each of those now at 300ppm. Last crop was a nightmare so they've been stuck there too long. Should've been transplanted 2 weeks ago but hey ho. Get it done today hopefully

 

[NamTran]

Thanks. Nice set-up btw. Are those clones or grown from seeds?

 

[Barney86]

All from seed mate. These are gonna be the first i clone though. Gonna try and run them all year with some candy dawg kush that im just about to pop.

 

[LiberalThinker]

Planting in a root sponge like Root Riot seems more reliable. You can cut a space for the sponge in the rockwool later if it needs that. Presoaking in a weak seaweed extract solution in a glass for 12 hours first then into the sponge has given me 100% germination so far.

 

[NamTran]

All from seed mate. These are gonna be the first i clone though. Gonna try and run them all year with some candy dawg kush that im just about to pop.

Nice. I want to create a perpetual vertical system using a mother and its clone but my current housing situation doesn't allow me to.

Planting in a root sponge like Root Riot seems more reliable. You can cut a space for the sponge in the rockwool later if it needs that. Presoaking in a weak seaweed extract solution in a glass for 12 hours first then into the sponge has given me 100% germination so far.

I'll try germinating again and if it doesn't work I'll try Root Riot.