From my experience, plants do know what season it is even under lights and relatively constant temps - assuming there is some connection maintained to the outside world. I grow mine in the winter under MH lights - winter and summer growers. Granted, my grow room will be cooler in the winter months than in the fall and spring...but something else is going on, too. They definitely sense when the season is becoming more conducive to their growth (but the room also has windows and skylights) even under the constant 11 hours of HID lighting.

Depending upon how much ambient light they are getting from your window, your plants might benefit from a longer artificial light length in the summer, shorter in the winter.

Why do you keep them indoors year round and what kind of lights do you grow them under?

Tom

Thank you, Tom...I'll try adjusting my timer. My bigger plants are outside, but I don't put the little ones out because the space on my screened porch is limited, and the patio is too shady, has squirrels, and we've had a very wet Spring/Summer. I figure they might not grow as much, but are safer left inside. I have two stands like this, and the lights are T8s.

The light from the window does affect seasonal growth, especially flowering.

Do your plants bloom regularly? Healthy plants should flower every year. If they are, then there's no reason to change what you are doing. But if not...

The extra light in the summer probably is of no benefit, however reducing the winter day-length to 10-11 hours instead of 12 might be more natural.

The big downside to growing plants indoors year-round is the lack of day-night temperature variation.

Thank you for the suggestions, I'll try cutting back the light a little in the winter. Most of my plants do bloom at some point during the year, I guess I'm just impatient for them to grow!