the problem you run into using pineapple juice and orange juice is that they are WAY acidic, and you coukd screw your stuff up. the food coloring idea does work. if you have plants going, pick yourself an insignificant lower branch. put some water in a vase, and die the shit out of the water with food coloring. put the branch in the food colored water, and within a few moments, the leaves will start to take on whatever color your water is. i myself didnt believe it until i tried it. i mixed red and blue to make purple, stuck a younge branch in the water and winin a couple of mnutes the leaves tips started turning purple.....pretty neat.
