leaves cupped?

I have my small 5x5 grow with 5 plants. 1 of which has the top leaves cupping. Im not sure if it is from being to close to the light. It does not feel to warm to the hand and others near it are not affected? I am using bag mix soil with food in it. Again none of the other plants are affected? My thought is a hot spot of nutes not mixed well enuf. Im not sure if it is too much or not enuf of something. Any advice? Gonna try to post sum pics.

1.Looks like heat stress, is the affected plant directly under the light?<<remedy, rotate your plant out further from the light with a shorter plant. 2.If its not heat stress then it's more than likely moisture stress<<too much moisture, remedy let your soil dry out almost completely before watering again. 3.Last but not least it could be a calcium deficiency<<remedy, get some Epsom salts mix about a 1/2tbsp with a gallon water and foliar feed it, repeat until deficiency is corrected. I would check the possible problems in the order I posted to ensure you don't over feed or under water causing more problems. Good luck and PLEASE POST YOUR RESULTS, a lot of RIU members get the needed advice and never actually post what the problem and remedy was making the SEARCH function almost useless in most cases.