Spraying the plants with water isn't bad for them at all. If you are spraying them too much you could raise the humidity level, but you are also cleaning dust and particles off the leaves so the stoma can breathe better also. It's best to do it in the morning, when it's not too hot, light can reflect through the water droplets and actually burn the plant if it is outdoors. You can also add small amounts of organic fertilizer to the water you mist them with once a week to foliar feed them. This is once again best done in the morning hours when the stoma are more open and can absorb the nutrients that the plant needs a lot better. What type of fertilizer are you going to use???