Whip and tongue burned leaves

I’m trying to grow some grafted (whip and tongue) rose plants. They are small (not even the size of a pencil). I have them in a huge white styro cooler with plastic sealed over the top. The light is 3" from the top of the cooler. The leaves are burning, but new (grafted) sprouts are growing. I am putting ice packs in there and it seems to help. Is the light too close or is this pretty common? The hybridizing family is filled with wonderful, brilliant people, I wondered if you (the green thumbed masses) could help this green grafter. Thank you, Tina