health Black/dark spots on seedling's first leaves

johnnyfive

johnnyfive

Hi.
 
I just germinated a Jamaican Yellow a few weeks ago. The third set of leaves is starting to appear but the first set of leaves have some dark-black spots on them. Any clue what it might be?
I'm growing them in an indoor grow tent with temperatures above 70F/21ºC during the night and 75-80F/24-27ºC during the day (250W HPS).
 
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Cheers
 
Looks to me like the cotyledons falling off which is natural, unless those are actually the true leaves in which case I'd check for pests with a magnifying glass.
 
I thought that too, but wouldn't the leaves be pointing upwards and more narrow if that were the case?  It still very well could be, I would check for mites as well, could be honeydew; also how close is the light source to the little guy?
 
do you have air flow ? , whats your water schedule ? and how much ?  could be genetic , light to close , bad soil , lots of things !      
 
I'm using a 50-50  mixture of perlite and vermuculite but started the seed in jiffy.
'm not overwatering the seedling but try to keep the mixture moist.
I suspected of excess light and moved the seedling far from a 250W HPS (before it was ~30cm far from the lamp).
 
50-50 mix of perlite and vermiculite??
that's going to have zero nutrients in it...not a good growing media I would think...
 
unless I misunderstood what you meant...then you should get them into some normal potting mix asap.
 
I'm using this 50-50 mix with additional nutes in order to move the seedling to a DWC system as soon as the roots are long enough. Not a good idea?
 
 
nzchili said:
50-50 mix of perlite and vermiculite??
that's going to have zero nutrients in it...not a good growing media I would think...
 
unless I misunderstood what you meant...then you should get them into some normal potting mix asap.
Click to expand...
 
 
I would go ahead and throw it in the dwc,  in my experience once you hit a true set of leaves and set it in, the roots find the water :p (mind you I have only used dwc for 5-6 harvests) see what others here have to say as well; plenty of knowledge.
 
Jeshwa said:
I would go ahead and throw it in the dwc,  in my experience once you hit a true set of leaves and set it in, the roots find the water :P (mind you I have only used dwc for 5-6 harvests) see what others here have to say as well; plenty of knowledge.
Click to expand...
 
Jeshwa, if I fill the DWC net pot with clay balls (to prevent light from reaching the reservoir too), the seedling's roots stay far from the water. How are you doing it? My net pot is quite big.
 
I have only ever used 5 gallon buckets, I am not sure how yours look underneath but around the time the cotyledons start falling off the roots are usually long enough to dangle out of the pot jjuuussstt touching the water, like I said, not quite sure the set up but if you feel the roots won't be close enough to the source then wait a while until comfortable, it is your grow afterall.
 
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