Phalaenopsis grow continuously throughout the year without a rest period so they will always need water and fertilizer. But in the winter months the days are much shorter, the sun light is less intense and the temperatures are lower. For all those reasons phals require less water and less fertilizer. I just read an article about a study done with commercial phal growers. It said that after phal spikes reach 10" in legth fertilizing or not fertilizing made no difference in flower count or size. It did say that phals that were given nitrogen while in bloom held their blooms longer than those that didn't receive nitrogen. I don't use Superthrive but I do know many growers who love it.