Not really, interupting the light/dark schedule is stressful to the plants. A few min. here and there shouldn't make much difference, but prolonged exposure to light during the dark schedule is not good for them. If you must work on them during thier night cycle, get a green light. Make sure there is no other ambient light and use the green light only. It won't effect the plants photosynthesis (atleast not noticeably) and will allow you to do what you need to. A green cfl from Homedepot will work fine. Happy Growing.