New to rockwool

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phantom grower

Member
First rockwool run here. My first question is about drybacks. For the first couple days of being in the rockwool I have been taking the fully saturated weight and allowing it to dryback to 10-20% of that total weight but it looks like I'm still getting signs of over watering. Please correct me if u see something wrong. 600ppm 2 weeks old. I feed once a day and allow it to dryback for around 24 hours and sometimes I have to force the dry w a towel
 
TCH

TCH

Well-Known Member
phantom grower said:
First rockwool run here. My first question is about drybacks. For the first couple days of being in the rockwool I have been taking the fully saturated weight and allowing it to dryback to 10-20% of that total weight but it looks like I'm still getting signs of over watering. Please correct me if u see something wrong. 600ppm 2 weeks old. I feed once a day and allow it to dryback for around 24 hours and sometimes I have to force the dry w a towel
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I dont see any pics if you posted them. Also, can you not wait another day to water them? I haven't grown in Rockwool, so I'm not sure if that's an option
 
P

phantom grower

Member
TCH said:
I dont see any pics if you posted them. Also, can you not wait another day to water them? I haven't grown in Rockwool, so I'm not sure if that's an option
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I definitely can but from wat I have learned about rockwool, the only way the roots get oxygen is from feeds. So if I go another 24hrs then I'm afraid my plants will look even worse. Also wen rockwool drys back too much the ppm spikes because the same nutes are left in the block w less water
 
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J. Rocket

J. Rocket

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"first couple days" doesnt give much info. a timeline would help...
rockwool what? slab, loose, block...
 
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phantom grower

Member
J. Rocket said:
also 80-90% is excessive dryback.
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I may have typed it wrong. Since being in the 3inch rockwool cubes I have fully saturated all 3 days, watering once a day. Fully saturated weight is about 460g and I re saturate wen it gets anywhere from 414g to 370g. Is that considered 80% or 20 % dryback
 
J. Rocket

J. Rocket

Well-Known Member
3" cube is very small for cannabis. I use 6".
the dryback amount isnt fixed, it changes from seedling (less) to maturing plant (more).

plant age/timeline and pics help.
hard to give specifics without.
 
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phantom grower

Member
J. Rocket said:
3" cube is very small for cannabis. I use 6".
the dryback amount isnt fixed, it changes from seedling (less) to maturing plant (more).

plant age/timeline and pics help.
hard to give specifics without.
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I was kind of weighing my options because I figured if I started a seedling in the 6inch it would stay too saturated so I would have to feed less, therefore giving my roots less oxygen. So I decided to start w the smaller cube and put it on top of or in the 6s I have. They are just 2 weeks old so really still in seedling stage. For the first week or so they were in root riots cubes then I put those plugs into the 3in rockwool I had. I can get some pics for u. But does a 20ish% dryback sound accurate?
 
J. Rocket

J. Rocket

Well-Known Member
phantom grower said:
I was kind of weighing my options because I figured if I started a seedling in the 6inch it would stay too saturated so I would have to feed less, therefore giving my roots less oxygen. So I decided to start w the smaller cube and put it on top of or in the 6s I have. They are just 2 weeks old so really still in seedling stage. For the first week or so they were in root riots cubes then I put those plugs into the 3in rockwool I had. I can get some pics for u. But does a 20ish% dryback sound accurate?
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6" just holds more ...8x the volume.
when you water to run-off it draws air/o2 in.
blocks have a moisture gradient, drier at the top than the bottom, even when fully saturated(after run-off).

didnt your blocks have a plastic wrap on them?
 
J. Rocket

J. Rocket

Well-Known Member
Its not helpful, I'll say that.
keeps the roots contained and the light off of them. also helps keep feedings contained.
more block surface area exposed means evaporation which will leave dried nutes behind.
I asume they are gone with the trash?
 
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phantom grower

Member
I haven't tossed em, no. I'm going to keep them regardless, for the experience. But these also aren't my final blocks. I plan on cutting a hole in the 6
 
Tolerance Break

Tolerance Break

Well-Known Member
600 ppm is waaaay to high for plants that small and the rockwool is way too saturated.

You can either re wrap the cubes in panda film or cover them in coco pellets.

You dont need excessive dryback and you don't need to force anything. At that size I would only be feeding every 3 days, but without the wrapper, I'm sure they're having trouble holding water, which is causing additional salt build up.

Rockwool is very easy until you make it complicated. I had a wonderful teacher and i still made it overly complicated my first cpuple grows. You have to play with it and take notes to find what works with your system, but the result is a very forgiving set and forget system (don't actually forget to check on them once every couple days at least, been there, done that, killed a plant lol)
 
P

phantom grower

Member
Tolerance Break said:
600 ppm is waaaay to high for plants that small and the rockwool is way too saturated.

You can either re wrap the cubes in panda film or cover them in coco pellets.

You dont need excessive dryback and you don't need to force anything. At that size I would only be feeding every 3 days, but without the wrapper, I'm sure they're having trouble holding water, which is causing additional salt build up.

Rockwool is very easy until you make it complicated. I had a wonderful teacher and i still made it overly complicated my first cpuple grows. You have to play with it and take notes to find what works with your system, but the result is a very forgiving set and forget system (don't actually forget to check on them once every couple days at least, been there, done that, killed a plant lol)
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Thank u!!
 
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