Tree ferns do not need to be fed as they derive their nutrients from the decaying matter of plants and insects that collect in their tops. I personally believe in the advice of doing nothing when it comes to caring for tree ferns. The most important things for tree ferns are protection from strong winds and regular watering. While they do not require a large amount of water, frequent watering is essential. The brown water from decomposed leaves can be beneficial, but not necessary. Overall, watering is the key factor in maintaining healthy tree ferns.