^^^ all very good advice. You're going to need a total of 4 23w bulbs to sustain one plant.1 23w bulb for 2 plants? That's nowhere near enough light, not even for one plant..
buy some Y adaptors and get at least 2 42watters in there and move the light to within 2" of the plants. As the plant grows you'll need to add more light - really you'd want at least 4 42w per plant and you'll need to make sure you have the 2700k ones for when you switch to a 12/12 lighting cycle to flower.
lastly, get a PC fan in there blowing on the plants to help strengthen up their stems, otherwise they may get top heavy and fall over.