All your seedlings are best grown in full sun, not usually in short supply in July. If you are using florescent grow lights, it is not possible to approach the intensity of sun light, so you should not expect the same growth. As soon as you can, I would put them in the sunshine. Al

They are actually out in the sun whenever it's not raining or too windy. I was asking about the time under lamps only because i'd need to know when i bring them inside. So if they cannot be outside due to rain/whatever, how long should the lights be on?

Once you've hardened them off and exposed them to outside conditions, there is no reason to bring them back in. They should be in a suitable growing medium in their pots, and pots should have adequate, functioning drainage holes. They will be fine in rain and still getting more light on a rainy overcast day outdoors than you can give them inside.

i highly doubt they would be fine outdoors in the storm we just had. 70mph winds that took out most of the trees in our neighborhood. most people are without power at the moment. i think that storm was more then enough to toss them around. even without the wind just the amount of water coming down would have uprooted them.

I know I wouldn't leave any of my seedlings out in any storms! You should keep them under the lights at least 18 hours a day, and as close to the light as possible when indoors. Hope this helps :)

I have to agree with the outdoors voters. Apples are totally hardy and would be much healthier and happier outdoors. Once hardened off - and that is important - there is no reason to waste energy on growlights. You could put them under cover if a storm was threatening. They also need to go dormant come winter to remain healthy and they won't do that under lights indoors.

Outside definitely...Even in a hurricane the seedling is likely to be unaffected unless a tree drops right on it and crushes it. The wind just plain isn't going that fast that close to the ground and the seedling is tiny and has no wind loading....big tall trees are in danger of high winds, young trees are not.