Laurel thinks that Miracle-Gro stresses plants and insists on organic.

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Bacterial Speck

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Early Blight

Tomato Problem Solver or use the resources here at GardenWeb.

There are many things that can stress a plant Feldon, but none of them have any real meaning unless a specific pathogen is in an area and has an opportunity to infect. YOur larger question has to do with disease tolerance and those ambient parameters that might actually induce disease.

And Laurel knows stress without a pathogen present is meaningless when it comes to disease b/c I know she knows. If she wants to garden organically, as do many, that's fine with me.

But if you're inferrring that gardening non-organically is stressful and allows for disease development, then I hace problems with that b'c you've left out of the equation the presence or absence of that possible pathogen.

But this isn't answering the question posted in this thread.

However, we've got a situation here where there are yellow spots on the leaves with seedlings still in the house under lights.

If it were me I think I'd ignore it. You've mentioned only yellow spots and that can sometimes come from watering, your Brandywine has PL foliage that's normally dark green, so that gets accentuated when talking about foliage becoming pale.

How long have you left the lights on each day?

How far away from hardening off are you?

So ALL the spots are yellow and you see no darker grey or brown centers, right?

How big are the spots and what is their shape?

Carolyn

I've got the same issue. My tomato seedlings are one month old and looking stocky and spry, but the color is an insipid green, with some showing shades of yellow (no spots), very different from the dark green you see with nursery seedlings. They are under conventional fluorescent bulbs which are continuously on. I thought chlorosis at first, but I'm not sure what it might be.

Please help!

Hi
Let the seedlings sleep at least 6 hours per night and the new leafs will be green.
Bye Ingo