I can't offer personal experience with MH, but I have peppers growing under LEDs. I hope the plant makes it, though -- it had a nasty root infestation a while back and lost a lot of leaves, and despite me killing off the little buggers and transplanting the plant to a new pot, some of the leaves are still dying off. I think that the rate of leaf loss has slowed down, though, and either way, the peppers have continued to grow the whole time. Honestly, I wish the plant would prioritize its leaves and roots over its fruit, but I can't control that.

Perhaps I'll give it another dose of pyrethrin in a day or two to make sure the buggers aren't coming back.

I also rooted a number of tomato suckers recently, but since they were just rooted, they're not to the flowering stage yet. I also have an eggplant whose flowers just opened up a few days ago. All of my non-pepper plants are doing great, health-wise.

I guess i should be more specific,for the first time I started all my plants indoors under a MH. They all grew great, Actually got bigger than i wanted before i put them outside. Some of the peppers got close to 20 inches tall and had lots of flowers on and a few small peppers. I should mention that they did not stretch and get leggy they were thick. So it got me wondering if i kept them under the MH, could I have a constant supply of peppers grown indoors? Or would i have to switch to HPS to get proper light levels, I know thats what you are supose to do, but my question is would a mh work to produce good peppers and tomatoes?

If I am not mistaken you can successfully grow either peppers or tomatoes under a MH bulb, but, a hps light would increase your yield 25%-30%. Remember MH bulbs mimic high noon sun rich in blues which are great for vegging. They produce less overall lumens per watt. If you are truly interested in trying to get the most out of your plants I would definitely consider a hps bulb. These bulbs have a greater red-orange spectrum and greater overall lumen output per watt. Since your dealing with 400 watts total you really are only working with about a solid 4x4 grow area. This means you could most likely get good output from a very well trimmed tomato plant and a very well manicured pepper plant. I wouldn't try to do to much unless you want to invest in a stronger setup though. 400 HPS would be better for yields.