O is it only peat and perlite? Could be a PH problem. It looks like a water issue to me though. Like the little guy is getting dry and shriveling at the base. I wish I had a picture of how close I use to get my CFL lamps. They were very close like a few inches away but they were 26W bulbs. I made sure I had good air flow across the bulbs to cool them and the surface of the bulb base usually was in the mid 70* range. I tried not blowing a fan on my bulbs and turned them off when the temps got to 148* and started to smell like hot electronics. Keeping a light breeze blowing on your bulbs is important. Your bulbs are larger so they will be hotter but even my 250W CFL I can touch the base of the bulb when it is on. Its pretty worm but I can touch the base with out burning my fingers. I put my 250 about 8" away. I would try different soil. Were are you getting your water from?