Clone??? your kidding right? dude you must be using flourescent light...need more of it or switch to Metal Halide. if you are using flouro, you can get as close as 2-4". MH/HPS 10" and more. Whatever you decide with the light, it would help you to put up a white or shiny reflective backround so any of the light you do have is at least being reflected back to the plants as much as possible, but that alone will not solve the problem. you need to hurry up and add more light otherwise you will have supertall plants with long, weak branches and low yields.