Peggy,

I usually try to keep my lights a two or three inches above my seedlings. If the leaves turned yellow, the problem may not be with your lights. Tomato seedlings are usually pretty trouble-free if there isn't a problem with their growing conditions.

Perhaps you could provide some details about the growing medium, how it is watered, etc. I usually keep my seedlings under a humidity dome until they emerge, at which time I remove the humidity dome. I don't provide them any nutrition until they get their first "true" leaves.

Then I use a weak (¼ teaspoon per gallon) nutrient solution, complete with trace elements like iron, magnesium, manganese, boron, molybdenum, zinc, etc. After the plants get really big I add some calcium in the form of dilute calcium nitrate. But never get your indoor nutrient solution stronger than one teaspoon per gallon.

MM

I had not moved the lights up high enough after they emerged. Too close to the lights. The new leaves, since moving the lights up, are a rich green, the way I expected them to look.

Thanks for the advice. Learn something new every day.

"normal office light type of tubes"? That tells me nothing. Do you mean, incandescent? These are the worse possible type of light to use. The next step up would be fluorescent. With a 4' fluorescent, I recommend between 1/4" and 3" from the leaves.

lermer,

I suspect that by, "normal office light type of tubes", Peggy meant fluorescent tubes, for which your recommendation would be appropriate, although ¼" is cutting it rather close. Many of my plants grow more than that overnight.

MM