It's probably shock... needed to be acclimated, they are outdoor plants here, so can take a lot of heat and sun.

I too am having a croton problem. I have three crotons in the same area of my apartment. They receive moderate indirect sunlight and approximately 12 to 14 hours of fluorescent light per day. I purchased them about 7 weeks ago and repotted them about 3 weeks after that in a well-known potting soil containing fertilizer. They seemed to endure that very well, but in the last few days one of them has lost 3 or 4 leaves.

The fallen leaves are very yellow where they should be green. I think that they are newer leaves, but I could be wrong. They arenÂt curled up at all, and donÂt have any brown edges. I think that they all came from the lower part of the stem  the newer leaves at the top of the plant seem fine and are very green.

IÂve watered all three plants at the same time, but I canÂt say for certain that they received the same amount. Several days ago, the plant that lost leaves seemed dryer than the other two so I gave it an extra bit of water. Any suggestions would be greatly appreciated.