Yellow spots on seedling.

Hello, I am still rather new at all of this. I started 4 babies from seeds. All 4 are GDP. They are all very healthy and growing very well. They are about 3 weeks old at this point. They are all in FFOF soil. I am using a 400w MH atm for vegging and the temps run about 86*F highs and about 70*F at the low point. Average is about 76*F.

Onto my issue: the one seedling I have pictures of has been displaying small yellow spots on all of the leaves. Two other seedlings have a little bit of the same and the last one shows no signs of it. It started about a week and a half ago. Some of the dots have tiny little black spots around it, which makes it look like possibly moths have been munching on my ladies. The other two that have little spots have the little black dots on every yellow spot, but the one with the most of them has some spots that have no little black spots, it just looks like a discoloration. I have checked all over them with and without a 100x scope and have seen no pests, but I have seen a moth or two get away from me inside the grow tent.

So here are the questions: does this look more like pest damage or more like fungus? If this is pest damage, how do I stop the moths or flies from attacking them? If this is fungus, what do I do? If it is, it has not stunted the growth (compared to the other ones), but should I get rid of it, even though it has not spread to any of my larger plants in the same room?

Any help is greatly appreciated and I would be happy to answer any questions to supply more information. Thank you.

Could be a pH issue, what is your pH?

I water them with 6.5 water. They all get the same thing which is weird. I have heard that ocean Forrest is a hot soil, so maybe this one was just affected more.

Bump. Anyone ever have this before and care to chime in?

What does the underside of the foliage look like? Could possibly be mites they attack from underneath your foliage any pest oil will cure that as long as you cover them from underneath wouldn't use a systemic pesticide on your babies especially ones you will be smoking...dose not look like a fungal or nutrient problem

Mites are difficult to see but you will notice little dots under the leaf you will notice grey dots starting to form all over the tops of your foliage as they suck the sap from below hard to tell from your pictures but does look like its a def possibly check under foliage and let me know

cann.i.bliss said:

What does the underside of the foliage look like? Could possibly be mites they attack from underneath your foliage any pest oil will cure that as long as you cover them from underneath wouldn't use a systemic pesticide on your babies especially ones you will be smoking...dose not look like a fungal or nutrient problem

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Thanks for your reply. I have not seen any mites, and my more experienced friend came over and that was the first thing he looked for and determined I didn't have any. I use a 100x microscope on them and haven't seen any mites either. Could they be hiding somewhere else? Like in the soil or something? I would absolutely hate if I had mites so I might do a light spray regardless of visible pests just to make sure. Thanks again.

cann.i.bliss said:

Mites are difficult to see but you will notice little dots under the leaf you will notice grey dots starting to form all over the tops of your foliage as they suck the sap from below hard to tell from your pictures but does look like its a def possibly check under foliage and let me know

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I'll do an extremely thorough search right now and check back in, thank you.

-Dodge- said:

I'll do an extremely thorough search right now and check back in, thank you.

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if you can't see any signs of mites only other thing it could be is early signs of powdery mildew, what is your air circulation like? And how do you water your plant? Hard to tell from the pic but its either got to be mites or powdery mildew by the grey/white dots on the top of the foliage to treat powdery mildew you need a fungicide preferably a powder one you mix with water but you need to look at your air circulation and watering habits as that is how it forms

Low Ca makes spots like that too.

Powdery mildew damage




Mite damage

cann.i.bliss said:

if you can't see any signs of mites only other thing it could be is early signs of powdery mildew, what is your air circulation like? And how do you water your plant? Hard to tell from the pic but its either got to be mites or powdery mildew by the grey/white dots on the top of the foliage to treat powdery mildew you need a fungicide preferably a powder one you mix with water but you need to look at your air circulation and watering habits as that is how it forms

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My air circulation is very good I believe. I have one intake coming straight from the window and an exhaust fan. Also on oscillating fan always running on the plants and one dedicated fan pointed on the light. I leave the tent open during sunlight and partially close it at night.
As for watering, I give them water about every 4 days. I do not touch any leaves with water, but I have been doing it while the light is on, I have yet to start watering in the early morning before the light is on even though I should be. At one point when it was pretty hot about 2 weeks ago I had a humidifier that was pointed way too close to the seedlings so I'm sure they got damp/ too moist. I only had that working that way for a few days before I realized that was a bad idea. I would think it was that although the new growth is still exhibiting the same problem. Thanks for the help and any further ideas.

hexthat said:

Low Ca makes spots like that too.

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Thanks, I'll look into that. I haven't started feeding them yet, so maybe that could have something to do with it.

hexthat said:

Low Ca makes spots like that too.

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Could be a little bit of calcium deficiency if you used a poor quality soil or nutrients can't imagine seeing it that early tho, but haven't seen calcium deficiency cause that grey powder like substance on foliage but is a most definate possibility with the yellow splocthing

cann.i.bliss said:

View attachment 3168609
Powdery mildew damage



View attachment 3168610
Mite damage

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I'm sure that picture of mite damage is in a late stage of damage, but it doesn't quite look the same to me. Idk though, I'm going to search for more pictures and see if they look the same. Thanks.

-Dodge- said:

I'm sure that picture of mite damage is in a late stage of damage, but it doesn't quite look the same to me. Idk though, I'm going to search for more pictures and see if they look the same. Thanks.

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yeah is a very late stage if it dosent rub off the plant then it won't be mildew

Have you noticed any whitefly on them at all?

cann.i.bliss said:

Have you noticed any whitefly on them at all?

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There are a few flies that I have seen in the tent and have been unable to catch them. I'm not sure if they are white flies, they just look like small gnats. I also haven't seen them on the seedlings, but if it is them I'm sure they would feast when I'm not there. I do see very small black dots right near some of the discoloration making me think something was nibbling on them. Could they be wreaking all this havoc? And if so should I just get some sticky paper to catch them? Thanks for the help.

-Dodge- said:

There are a few flies that I have seen in the tent and have been unable to catch them. I'm not sure if they are white flies, they just look like small gnats. I also haven't seen them on the seedlings, but if it is them I'm sure they would feast when I'm not there. I do see very small black dots right near some of the discoloration making me think something was nibbling on them. Could they be wreaking all this havoc? And if so should I just get some sticky paper to catch them? Thanks for the help.

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They are like a small white moth usually there will be a fair few of them they suck sap from the underside of the foliage again they also lay eggs on the foliage which would be quite visible I have never seen a deficiency exhibiting that damage before and I can't imagine young seedlings being deficient in anything as most water contain a lot of. Your trace elements, calcium etc, look up some whitefly damage and see what u think also keep an eye out for insects

Now that you say you have seen gnats in your tent I would be pretty confident to say it would be fungus gnat damage

They are nasty lil shots yellow sticky traps will work but be aware they lay There eggs in the soil/potting mix and when they hatch the larvae will feed on your roots so you will be in trouble if its a big infestation as every gnat
can lay upto 300eggs...
You can get a pesticide you can water through your soil that will kill them they are very common on young seedlings especially in green/hot houses