Hey guys new here. This is my first grow ever. Going to be growing in RDWC. Started germinating these autoflowers in 4" rockwool. Think that may be my first problem. Had light on them 24/7 since they sprouted. I had about 300 umols on them at first. Trimmed that down to 150 thinking they may have been getting burnt. But the 3 larger seedlings seem to still slowly be getting worse. It's about day 10 on these seedlings. They seem to be turning yellowish and the very tips turning pale / brown. Ill post pictures. Ive been really unsure of how wet I should have the rockwool and how often I should re add water. I am using distilled water currently with a small amount of ORCA. No nutrients yet. Have the 3 part GH flora series ill be using for nutes. I have these growing in a propagation dome with temps around 78. The humidity has fluctuated between 70-90 remaining usually around 75-80. Let me know for any further information. Any feedback is much appreciated!
Seedling Help
- Thread starter Uffda_Pal
- Start date
Dboybudz
Well-Known Member
Humidity is a bit high aim for low 60s. Also seedlings don't need much light at first just a fluorescent or t8 for a couple weeks. Others will chime in to help ya better with watering I use soil.
MissinThe90’sStrains
Well-Known Member
Generally, plants need to start getting food once they sprout their first set of true leaves. Rockwool is inert, so there’s no food in there. If you’re using distilled water in a medium with no food, and haven’t fed yet and it’s day 10, they’re probably starving.
coreywebster
Well-Known Member
300umol at 24/7.. that's not good, add In the lack of nutrients, the RO water with no buffering ..I'm surprised they ain't dead.
Get your water and add your calmag at suggested rate for ro water, add your nutrients and ph it.
Get your water and add your calmag at suggested rate for ro water, add your nutrients and ph it.
I appreciate that. RO without buffering? Is that the cal mag? I do have cal mag. Premix in gallon then drip feed into rockwool with syringe? Should I add real low nutrients as well? Thought from what I understood ro water was fine in seedling. To start nutrients at roughly week 2 (autoflower).
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Seedlings cannot take up nutrients until they sprout their first true leaves. The cotyledons provide nutrients because the root system is not mature enough to take up nutrients. By the time the first true leaves have sprouted, the root system has matured to the point where it can take up fertilizer.
Per the data at the bottom of the posting, I feed my plants ~100µmol for the first few days and then get to 300µmol. I've done 12± grows and haven't even given my seedlings less than 300µmol.
Out of interest, how are you measuring light?
Back to your issue—welcome to "the carnage club". That's a club that I founded when I started growing (again) in 2021. I used rock wool and, as a result of giving them too much water,they died I killed them.
and since once wasn't enough, I slaughtered another set:
Rather than destroy another $40/50/60 of seeds while trying to learn how to not give them too much water, I chose different method of germination and went with Rapid Rooters. I'd hard to f•ck things up with Rapid Rooters. They're about $20 for a bag of 50 and, as best I can tell, they're idiot proof.
For a few grows, I kid you not, I was giving them water using an eye dropper. I even went to far as to weigh RR before and after so I could do it "just right". After a few grows using RR's, I hypothesized that they were designed so that you couldn't overwater them, so I tried and I couldn't.
If you remove the excess water from the rockwool, they might make it. If not, grab a bag of Rapid Rooters (there's another product called Root Riot) and you will dramatically increase your chances of success.
Below are the average PPFD values for my most recent grow. These values are typical of my grows since 2022 when I switched from legacy light values which are from the CMH and HPS era, to using PPFD values from the LED era.
Duplicated PPFD values are most likely because I didn't measure light that day but am using the value from the previous day. Light was sample at the plant center as a seedling and then multiple samples, in a grid fashion, through veg and early flower. When the colas were maturing, I sample each cola. The values below are averages but PPFD rarely exceeded 1100µmol.
I grow in ambient CO2 and the PPFD values were measured using a calibrated Apogee.
Per the data at the bottom of the posting, I feed my plants ~100µmol for the first few days and then get to 300µmol. I've done 12± grows and haven't even given my seedlings less than 300µmol.
Out of interest, how are you measuring light?
Back to your issue—welcome to "the carnage club". That's a club that I founded when I started growing (again) in 2021. I used rock wool and, as a result of giving them too much water,
and since once wasn't enough, I slaughtered another set:
Rather than destroy another $40/50/60 of seeds while trying to learn how to not give them too much water, I chose different method of germination and went with Rapid Rooters. I'd hard to f•ck things up with Rapid Rooters. They're about $20 for a bag of 50 and, as best I can tell, they're idiot proof.
For a few grows, I kid you not, I was giving them water using an eye dropper. I even went to far as to weigh RR before and after so I could do it "just right". After a few grows using RR's, I hypothesized that they were designed so that you couldn't overwater them, so I tried and I couldn't.
If you remove the excess water from the rockwool, they might make it. If not, grab a bag of Rapid Rooters (there's another product called Root Riot) and you will dramatically increase your chances of success.
Below are the average PPFD values for my most recent grow. These values are typical of my grows since 2022 when I switched from legacy light values which are from the CMH and HPS era, to using PPFD values from the LED era.
Duplicated PPFD values are most likely because I didn't measure light that day but am using the value from the previous day. Light was sample at the plant center as a seedling and then multiple samples, in a grid fashion, through veg and early flower. When the colas were maturing, I sample each cola. The values below are averages but PPFD rarely exceeded 1100µmol.
I grow in ambient CO2 and the PPFD values were measured using a calibrated Apogee.
MickFoster
Well-Known Member
I hate rockwool........the only time I used it my seedlings died from damping off. I prefer rapid rooters.
