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Seedling problems last 72h – looking for feedback
CannaArchivestarted grow question 1d ago
Looking for feedback. Seeds germinated in water + H₂O₂, then placed in new coco tabs under a humidity dome (70–85% RH, ~23 °C). 1x seedling developed weak stems,1x yellow cotyledons and stalled growth. I suspect coco tabs + high RH or low temp . Thoughts and restart advice?
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Chucky324answered grow question 1d ago
Hello. I've seen this with the coco pellets before.
I've switched back to peat pellets and haven't had the same problem.
I suspect that the coco pellets are not ph correct... thus your problems.
Take the domes off and lower the light a bit... this will help to give your plants some needed solar energy.
Good Luck.
Green_clawsanswered grow question 1d ago
Yeah the dome will help the seed be in optimal conditions also help drop the case easier then this needs removing or it with damp off to mold. Can see the 1 on the right opened up brown so the seed might be at fault either way looks like mold has took hold. Good luck
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Ultravioletanswered grow question 1d ago
One of the main reasons to keep high rh during a seedlings life is nothing to do with growth but "playing it safe". To prevent the loss of water faster than the tiny seedling can uptake.
Heat and light from the growlight will dry out the topsoil in a couple hours or more depending on metrics you set. When the seedling is tiny it has no stem or leaves , it cannot store nutrients or water until she gets bigger. If she dries out even a bit at such a young age its insta kill.
Water 6-8" around the seedling then add a simple inorganic mulch around the seedling to prevent and slow the evaporation from surrounding soil.
I like to use burner liners from the dollar store as they are also highly reflective. Prevents drying out of root zone. All the air she needs. After a week or two once roots are bigger than a thumbnail. Then grow as normal.
Gluck pal.
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Ultravioletanswered grow question 1d ago
Dome is to maintain the even moisture to assist in breaking out the shell, once its soft. Once that shell is off as soon as you see green cotys she needs oxygen, airflow, ever so slightly. Don't use a dome, if you want to add a little humidity to help add a plastic bottle with open top so air can still get in. The lack of oxygen will stunt growth, outwieghing any benefit from the high rh.
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greenAFanswered grow question 1d ago
And if your airtemps are that low your rootzones for sure lower. It's like boxing with atleast one hand behind your back, getting temps up would be my first path forward
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greenAFanswered grow question 1d ago
70-80 RH is fine, 85 a lil high but even that fine early, but your temps are the main issue, way too low, I like being in the 80-82F range. If you can't get temps up its less than ideal and will probably struggle regardless, but can try and get that max rh down by 10% to raise that vpd some.
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