Seedlings in rockwool are not growing, but turn yellow and die

Sam&Max

Sam&Max

Active Member
I planted around 230 seedlings in rockwool.

They are not growing but the leaves are turning yellow and more and more of the seedlings are dying. I already lost more than 30 because of that.

I really don't know what it is.

I have HID lightning 400W in 120cm distance. I have running a big dehumidifier set at 65 percent. Seedlings are in small rockwool cubes in a heated plastic basin set at 26 degree celcius. I started fertilizing after a week. I use tap water and regulate the ph to 5.5 before feeding.

Problems started before fertilizing. In beginning I had t5 lights, but all of the plants stretched, so I hanged the lights lower but then the leaves hang down and wilted. That is when the shit started. I put the lights higher and then plants in the periphery started stretching because the tubes were too short. So I had to put the plants under HID lightning. 400 W distance 120cm. Since then the plants don't do anything anymore, the weaker plants slowly crumble... :-/

I am watering the plants once a day since the rockwool dries out really quick. I am not sure if I maybe overwater them. Because sometimes there still stands a bit water in the basin after I gave them water. The cubes soak themself full. If I dont do that they dry out too quickly. I don't cover the rockwool cubes as it is too many of the cubes. I mean how wet is too wet? Will my small roots be able to drown in rockwool? I heard there is so much air in rockwool that the plants can't drown. If there is residue water it is not so high.

It is a bit of a pity, as it is around 500 bucks worth of seeds. I am not sure what is the reason the plants are fucked up and if I need to start over. Maybe you can give me advice. Tomorrow I try to send pictures. I didn't want to post pictures because of security reasons. But in that case I will do.

(I was not able yet to install the air exchange fan of the room. The room doesn't get hot and is dehumidified. Also when I am working in there, the small plants should get enough CO2).

Are the plants maybe light burned and then overly sensitized to all other influences???
 
Esrgood4u

Esrgood4u

Well-Known Member
Sam&Max said:
I planted around 230 seedlings in rockwool.

They are not growing but the leaves are turning yellow and more and more of the seedlings are dying. I already lost more than 30 because of that.

I really don't know what it is.

I have HID lightning 400W in 120cm distance. I have running a big dehumidifier set at 65 percent. Seedlings are in small rockwool cubes in a heated plastic basin set at 26 degree celcius. I started fertilizing after a week. I use tap water and regulate the ph to 5.5 before feeding.

Problems started before fertilizing. In beginning I had t5 lights, but all of the plants stretched, so I hanged the lights lower but then the leaves hang down and wilted. That is when the shit started. I put the lights higher and then plants in the periphery started stretching because the tubes were too short. So I had to put the plants under HID lightning. 400 W distance 120cm. Since then the plants don't do anything anymore, the weaker plants slowly crumble... :-/

I am watering the plants once a day since the rockwool dries out really quick. I am not sure if I maybe overwater them. Because sometimes there still stands a bit water in the basin after I gave them water. The cubes soak themself full. If I dont do that they dry out too quickly. I don't cover the rockwool cubes as it is too many of the cubes. I mean how wet is too wet? Will my small roots be able to drown in rockwool? I heard there is so much air in rockwool that the plants can't drown. If there is residue water it is not so high.

It is a bit of a pity, as it is around 500 bucks worth of seeds. I am not sure what is the reason the plants are fucked up and if I need to start over. Maybe you can give me advice. Tomorrow I try to send pictures. I didn't want to post pictures because of security reasons. But in that case I will do.

(I was not able yet to install the air exchange fan of the room. The room doesn't get hot and is dehumidified. Also when I am working in there, the small plants should get enough CO2).

Are the plants maybe light burned and then overly sensitized to all other influences???
Click to expand...
I hate rock wool cubes. Even the ones that say are ph stable still drift. I'd do several soaks in PhD water squeeze slightly and ph test the water that comes out the cubes. I can guarantee the ph will have drifted.
 
Sam&Max

Sam&Max

Active Member
some pictures. But somehow I doubt that these are benficial.

I flushed each single cube with ph adjusted water several times and squeezed them a bit.

I lowered the HID light a little bit but reduced the wattage to 250W.

Also I lowered the temperature to 21 degrees.

I disinfected the basin and made sure that there is no residual water after flushing.

Also I added 1ml of H2O2 12% per Liter of Water for the flushing.

Tomorrow I will give fertilizer.

But I guess I need to buy some new seeds too.

Question: If I can rescue and stabilize the plants, will they show deficient qualities the rest of their lives, e.g. reduced yield, or will they behave normal? My plan was to select mother plants. If the plants show unusual traits because of the severe stress as seedlings, the choice might be flawed?

Oh and I contacted Cultilene and Grodan about the necessary pretreatment.
 

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Esrgood4u

Esrgood4u

Well-Known Member
Sam&Max said:
some pictures. But somehow I doubt that these are benficial.

I flushed each single cube with ph adjusted water several times and squeezed them a bit.

I lowered the HID light a little bit but reduced the wattage to 250W.

Also I lowered the temperature to 21 degrees.

I disinfected the basin and made sure that there is no residual water after flushing.

Also I added 1ml of H2O2 12% per Liter of Water for the flushing.

Tomorrow I will give fertilizer.

But I guess I need to buy some new seeds too.

Question: If I can rescue and stabilize the plants, will they show deficient qualities the rest of their lives, e.g. reduced yield, or will they behave normal? My plan was to select mother plants. If the plants show unusual traits because of the severe stress as seedlings, the choice might be flawed?

Oh and I contacted Cultilene and Grodan about the necessary pretreatment.
Click to expand...
They may bounce back. I'd give them a couple of days before I culled any. They are really stretching so you did right moving the light closer.
Nutrient wise I still wouldn't feed anything other than a root stimulant until the got there first set of true leaves first.
 
Cold$moke

Cold$moke

Well-Known Member
Your not feeding at 5.5 ph all the time are you?

Also the small blocks will only sustain a seedling for a few days before the roots come out of the bottom

After that the roots will airprune themselves and will yellow the plant from the bottom.
 
Jimdamick

Jimdamick

Well-Known Member
Sam&Max said:
some pictures. But somehow I doubt that these are benficial.

I flushed each single cube with ph adjusted water several times and squeezed them a bit.

I lowered the HID light a little bit but reduced the wattage to 250W.

Also I lowered the temperature to 21 degrees.

I disinfected the basin and made sure that there is no residual water after flushing.

Also I added 1ml of H2O2 12% per Liter of Water for the flushing.

Tomorrow I will give fertilizer.

But I guess I need to buy some new seeds too.

Question: If I can rescue and stabilize the plants, will they show deficient qualities the rest of their lives, e.g. reduced yield, or will they behave normal? My plan was to select mother plants. If the plants show unusual traits because of the severe stress as seedlings, the choice might be flawed?

Oh and I contacted Cultilene and Grodan about the necessary pretreatment.
Click to expand...
Why so many seeds? What are you going to do with them all?
I don't grow that many in a year, and I grow a lot.
Anyway, you have to repot now and feed, as rockwool holds no nutes and you need food right from the beginning.
You have to keep rockwool moist, not wet, or they will drown your roots.
I soak my cubes in 5.8 and 650 PPM with no issues, but I repot immediately after they sprout, like within 3 day's max.
You've got you work cut out for you, and I wish you luck
 
Sam&Max

Sam&Max

Active Member
I did read that I can let the roots air prune without problems.

Also I read that at least in the early phase of the seedling before they show their first pair of true leaves, no fertilization is needed. The plant lives from the nutrients in the seed leaves.

I did an indoor grow with 50 seeds SOG without problems. So now I was planning a SOG with 230 seeds and select some motherplants.
 
G

greenbookworm

Member
I've been growing in RW cubes for a few years. It root cuts just fine. But the seed germination is a little tough. Grodan says to put straight in cube with no pre-germination. I personally soak in ph'd water, then use a salad spinner to get all water out. Then water in fresh RO with no nutes. I dont squeeze the blocks ever. Lastly insert seed pointy side down into cube and immediately transplant into Hugo block. I use a shop light for the seedlings, about 6in above the Hugo block. As soon as the first set of leaves poke out I lightly water in a 200ppm nute solution. It doesnt work 100 percent of the time, but gives me enough starters to pick from. Now RW isnt my preferred method of growing, my wife made me give up soil due to me making messes all over the house. But it's super clean and will grow some serious dank.
 
Michael Huntherz

Michael Huntherz

Well-Known Member
Sam&Max said:
I planted around 230 seedlings in rockwool.

They are not growing but the leaves are turning yellow and more and more of the seedlings are dying. I already lost more than 30 because of that.

I really don't know what it is.

I have HID lightning 400W in 120cm distance. I have running a big dehumidifier set at 65 percent. Seedlings are in small rockwool cubes in a heated plastic basin set at 26 degree celcius. I started fertilizing after a week. I use tap water and regulate the ph to 5.5 before feeding.

Problems started before fertilizing. In beginning I had t5 lights, but all of the plants stretched, so I hanged the lights lower but then the leaves hang down and wilted. That is when the shit started. I put the lights higher and then plants in the periphery started stretching because the tubes were too short. So I had to put the plants under HID lightning. 400 W distance 120cm. Since then the plants don't do anything anymore, the weaker plants slowly crumble... :-/

I am watering the plants once a day since the rockwool dries out really quick. I am not sure if I maybe overwater them. Because sometimes there still stands a bit water in the basin after I gave them water. The cubes soak themself full. If I dont do that they dry out too quickly. I don't cover the rockwool cubes as it is too many of the cubes. I mean how wet is too wet? Will my small roots be able to drown in rockwool? I heard there is so much air in rockwool that the plants can't drown. If there is residue water it is not so high.

It is a bit of a pity, as it is around 500 bucks worth of seeds. I am not sure what is the reason the plants are fucked up and if I need to start over. Maybe you can give me advice. Tomorrow I try to send pictures. I didn't want to post pictures because of security reasons. But in that case I will do.

(I was not able yet to install the air exchange fan of the room. The room doesn't get hot and is dehumidified. Also when I am working in there, the small plants should get enough CO2).

Are the plants maybe light burned and then overly sensitized to all other influences???
Click to expand...
If you don't know what the hell you're doing...why so many plants? The feds can really get bent out of shape with anything over 100, watch your ass. I'm with Jim on this, except I'm not sure I wish you luck. You seem a bit foolish to me, and I want the cannabis community to look less stupid, whenever possible.
Airwalker16 said:
Use root riot cubes or rapid rioters next time. Rock wool sucks.
Click to expand...
You are talking out your ass. Stop.

Some of the most advanced indoor agricultural operations in the world use Rockwool. I strongly suggest you cease offering opinions with no basis in fact as if they are fact.
https://www.actahort.org/books/190/190_57.htm

Look, I don't think I'm someone special; I'm a meatbag with shoes, just like the rest of you pukes. But I'm begging you, can we all take a deep breath and use our goddamn brains for a minute before doing things like planting 230 seeds in a medium we aren't experienced with, or saying "Rock wool sucks" with absolutely no supporting facts?

rollitupmemberseverywhere said:
I just jumped out of an airplane, how do I use this parachute?
Click to expand...
rollitupmemberseverywhere said:
Oxygen sucks.
Click to expand...
Please, please, please stop with the stupidity and think before you act.
 
Jimdamick

Jimdamick

Well-Known Member
Michael Huntherz said:
If you don't know what the hell you're doing...why so many plants? The feds can really get bent out of shape with anything over 100, watch your ass. I'm with Jim on this, except I'm not sure I wish you luck. You seem a bit foolish to me, and I want the cannabis community to look less stupid, whenever possible.

You are talking out your ass. Stop.

Some of the most advanced indoor agricultural operations in the world use Rockwool. I strongly suggest you cease offering opinions with no basis in fact as if they are fact.
https://www.actahort.org/books/190/190_57.htm

Look, I don't think I'm someone special; I'm a meatbag with shoes, just like the rest of you pukes. But I'm begging you, can we all take a deep breath and use our goddamn brains for a minute before doing things like planting 230 seeds in a medium we aren't experienced with, or saying "Rock wool sucks" with absolutely no supporting facts?



Please, please, please stop with the stupidity and think before you act.
Click to expand...
A little harsh, but true.
 
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