Wow, the best I can grow is five at a time. I always do a mixed grow. Usually three varieties. This may help prevent total loss of a crop do to a single problem, spreading the risk. Besides I like comparing the plants as they grow, observing their different growth patterns and requirements as well as having a variety of bud. I have grown photos and autos together with no problems. It's all fun and variety is one of the joys of life.