Yellow in the center of seedlings

Greetings,

What a pleasure and relief to find this forum!

I've just started growing. I'm using a Phototron 9. Unfortunately, I was completely unaware (as recently as a couple of days ago) that one can find seeds online; as a result, I'm using some collected seeds from unknown sources. So I don't really know what I'm going to end up with. Next time, I'll know better.

Anyway, I don't have that many seedlings to choose from -- and several of them are exhibiting the characteristic shown in the photo: yellow inside the leaf (not along the edges or tips). From what I see on the FAQs, this might be an iron deficiency -- disappointing since I'm using the formulas that came with the Phototron and being very careful to follow the directions exactly. But before I assume anything, I thought it prudent to check here to see if anyone can confirm iron deficiency from the photo, or suggest that it might be something else.

Also, if anyone has any suggestions on ways to improve upon the standard Phototron nutrients and procedures, I'd be grateful to hear them.

Thank you,
Mitch

I have a bonzeyed female. I found her growing on the edge a parking lot at a fast food restaurant, A&W. I have never fed this plant any nutrients for the five months I've had her. She is on a diet of a couple drops of tap water every couple days. Despite the fact that she is deliberately being kept small she hasn't any obvious deficiencies at all. She lost her baby leaves. It's the correct colour, the leaves are nice and green and have the proper shape. So this isn't a deficiency problem with your seedling.

Have you been PHing the water you are giving the plant? I've been a stupid cheap lazy ass and skipped out on buying a meter and testing my water and my plant was showing those signs, you can see the aftermath on my YouTube channel in my Sig, the ph could be locking out iron intake.

Mine were the same. The sprout came up yellow when I was gone. Turned on the lights 8 hours later I had green leaves at 4 days old.

Thank you for all the swift (and reassuring) replies. I'm using distilled water (distilled at home) so I don't think pH should be an issue, but I'll test it anyway just to make sure. They're getting 24-hour light, so that's not it, but I'll just keep going and see what happens.

Many thanks again!

Mitch