Water mounted ferns or ferns grown in wire baskets by immersing the root ball in lukewarm water for 15 minutes biweekly. Outdoor ferns attached to trees should be watered with a can or hose biweekly as well. The roots should be allowed to dry slightly but never completely before you water them again.
Protect your elkhorn fern from direct sunlight. Elkhorn ferns grow on tree trunks in their native environment, where they receive only dappled sunlight. Indoors, filter sunlight with a sheer curtain.