Seedlings keep dying after transplant from rockwool

[Lucic1991]

I'm having problems with my seedlings dying after they sprout in rockwool cubes.

I have had a few successful grows in my basement grow room (it's finished, clean, and dry), but I've been having some problems my last three attempts. I start my seeds in rockwool cubes dipped in pH 5.5 bottled spring water, on the lid of a tupperware container with the top just gently sitting on top to trap moisture. I open it 2x/day to let air in and I have never had problems with the seeds sprouting. However, once they've sprouted, I transplant them and they have died the past three times. I use coco coir mixed with organic pearlite as a medium, with a 2" perlite bottom and a hole drilled into the 3-gallon bucket for drainage. I put my seedlings under a T-5 4-bulb light with 4 fluorescent 6400k bulbs that puts out 20k lumens for vegging, which I put them under once they've sprouted. (I have a 600W HPS that i switch to for flowering, but haven't gotten that far with my last few grows). I have a of small, indirect blowing fan, it's about 70 degrees F, 30%RH, I have a carbon filter, and no pests so I'm not sure what is going wrong with my plants but if anybody has any ideas I would appreciate the help! Should I be letting the seedlings sit under the lights in the cubes for awhile before transplanting? Am I transplanting them too early? Please help!

 

[MickFoster]

I have used rockwool before but I don't use it anymore. I'm sure it's your method and not the rockwool. When you say die - could you explain what happens? Does it just fall over? Sounds like damping off if that's what happens. Why are you starting in such a large container? What size rockwool cube are you using? Is the root coming out the bottom of the cube? If you have failed three times and have not changed your method, obviously you're doing something wrong. Have you considered using Rapid Rooter - I get nearly 100% success.

 

[Cold$moke]

I would say let the roots grow out of the cube before you transplant it

and lose the humidity dome unless its very dry

If you are transplanting before you get any true leaves. Then yea its probably to wet in the cubes to be in coco.

 

[ANC]

I would say let the roots grow out of the cube before you transplant it

Put half an inch of moist perlite under your cubes to aid with drainage and to protect long roots coming out the bottom.

 

[Mztoker]

I bet u got or you damaged the cubes. This same thing sorta happened to me. But i saved the 2 sprouts but pulling them up and doing some surgery to the cubes. When i transplanted after they sprouted i didnt wait till roots came out of bottom like i should have because of moister issues. Then i planted into solo cups with soiless mix. Well i remember that 2 of them i sorta wiggled and pushed down in the dirt to get it to the level i wanted. Thats where i think i fucked up cause what do you know 2 out of 12 started to die on me a few days later. I have it another day then said fuck it and ripped the cubes open gently. And what do you know i see the weirdest root tangle knot thing ever. I just planteded it back in the dirt out of the rockwool and bam they snapped back.

 

[Mztoker]

Long story short if those cubes get smashed up at all i think they sorta like trap the roots and shit

 

[Cold$moke]

It closes off the micro pores of the wool
Do not sqeeze lol

If you need to you can flick the water out but dont sqeeze

 

[MickFoster]

Foolproof.

 

[Cold$moke]

Not so, ive used RR. For many years

and after trying rockwool i love it for seeds.

I have my reasons

Not saying RR suck cause they dont.

But they have quirks as well i wont use the brown sponges again lol

 

[MickFoster]

Not so ive used RR. For many years and after trying rockwool i love it for seeds.

I have my reasons

Not saying RR suck cause they dont.

But they have quirks as well

Different strokes my friend. I didn't suggest that you use RR - you didn't ask for the help. Considering the OP was killing his seedlings using rockwool - I offered an alternative.

 

[Cold$moke]

Understood,

i simply made sure he knows they are not in fact perfect.. though i very much could be a fool
But after using Rr for over 8 years i made the switch and im happy

 

[chiqifella]

sounds like your rockwool is waterlogged. after a dip in water gently squeezing out the excess moisture like the package directions say is key.
first used rockwool, bummed out, they didnt compost
then addicted to RR, loved them, expensive, but pennies in the long run, they never seem to "biodegrade" either
but look less conspicuous in the outdoor veggie garden than rock wool.
Now....I dip the scraped cut in clonex and right to a draining cup of promix and another clear cup on top for a couple days for the final win!

 

[Cold$moke]

Ok if you gota sqeeze stuff go get RR as they are a sponge.

I like to sqeeze tities lol. But DO NOT SQEEZE WOOL AT ALL destroys the micro pores between the fibers

Rockwools doesnt biodegrade because its rock
Its already degraded lol. Just mash it up into your compost think of it as rock cotton

 

[Kingrow1]

I'm having problems with my seedlings dying after they sprout in rockwool cubes.

I have had a few successful grows in my basement grow room (it's finished, clean, and dry), but I've been having some problems my last three attempts. I start my seeds in rockwool cubes dipped in pH 5.5 bottled spring water, on the lid of a tupperware container with the top just gently sitting on top to trap moisture. I open it 2x/day to let air in and I have never had problems with the seeds sprouting. However, once they've sprouted, I transplant them and they have died the past three times. I use coco coir mixed with organic pearlite as a medium, with a 2" perlite bottom and a hole drilled into the 3-gallon bucket for drainage. I put my seedlings under a T-5 4-bulb light with 4 fluorescent 6400k bulbs that puts out 20k lumens for vegging, which I put them under once they've sprouted. (I have a 600W HPS that i switch to for flowering, but haven't gotten that far with my last few grows). I have a of small, indirect blowing fan, it's about 70 degrees F, 30%RH, I have a carbon filter, and no pests so I'm not sure what is going wrong with my plants but if anybody has any ideas I would appreciate the help! Should I be letting the seedlings sit under the lights in the cubes for awhile before transplanting? Am I transplanting them too early? Please help!

If your not adding some kind of nutrition or ferts to the rockwool they will die, even 0.1ec is better than nothing. Water is devoid of nutrients and as soon as you have roots you need an osmotic gradient, spring water wont cut it.

 

[MickFoster]

I soak mine in a 1/4 strength bloom solution.

 

[Kingrow1]

I soak mine in a 1/4 strength bloom solution.

Ive taken a pack of those fleximix root riots and squeezed all the liquid out, tested at 1200ppm, possibly they are pre fertilized but i found all root cubes and rockwool to be too much work so i stick with good old soil thesedays. Have you tested yours? im sure the fleximix has somthing in already but getying info from these companies is a pita

 

[Cold$moke]

I soak mine in a 1/4 strength bloom solution.

Same

The rockwool for me but i have soaked footer as well.

But i never thought to check the rooters.

Kingrow1 does do some nice seed work

 

[Lucic1991]

Thank you for all your help!

Yes each time the roots were showing out of the bottom before I transplanted them and I never squeezed the cubes, I dipped them for 3-5s and let them drip a few seconds before putting the seeds in. I live in a very dry climate it's 0% humidity if I don't have a humidifier on so the plastic is somewhat critical I think. I use 1.5" cubes.

My most current 2 are alive, I took them out of the tupperware as soon as they sprouted and put them about 5" under the lights (just in the cube, without anything else) and they're still alive today. When they die they just get brown and weak gradually and the stem can't support them (and I had a small fan indirectly blowing in the room).

 

[Cold$moke]

You need to shake that excess water out if the cube is dripping its too wet for seeds imo

Which is what sounds like is happening when they die...... dampening off

 

[Lucic1991]

Here is what they look like now. It is 90* F and 0% RH under the light. They both are pretty dry but with some slight moisture at the bottom of the cube. One has a root sticking out the bottom and one doesn't. I'm afraid to give them water because it seemed like they were too moist before, but they're pretty dry and I'm afraid to transplant them yet. Should I just mist them and maybe put them on a bed of pearlite so they can drain?