Potassium Sources

• Any array of well-balanced liquid fertilizer products may be used on staghorn ferns, especially if the formulations have elevated potassium levels. In the three-number fertilizer formula, potassium (K) is the third number in the string. For example, 5-20-15 reveals 15 percent potassium by fertilizer volume. Fish emulsion also contains sufficient levels of potassium for use on staghorn ferns. Granular, slow-release fertilizers aren't recommended, even if they have good potassium formulations. The granules, rich in salts, will not stick to the staghorn ferns and can cause burns on leaves when wetted.
  
  

Problems With Bananas

• While bananas do contain potassium, the fruit or peel does not translate well to fertilization of the staghorn fern. Rotting banana fruit or peel smells, attracts insects and can potentially cause some fungal rot on the shieldlike infertile leaves in the staghorn fern base. Bananas also do not supply a balanced amount of nitrogen and phosphorus, thereby requiring you to again fertilize with another product. Whether the staghorn fern is a large ball-shaped mass or a small plant, placement of a banana is problematic. Questions arise as to how to reach the fern to insert or lay a banana or how to hide the banana so that it's not seen as a major visual component of the fern.
  
  

Using Liquid Fertilizer

• Well-balanced liquid fertilizers allow you to evenly coat all foliage of the staghorn fern, resulting in a better overall feeding. Products with a basic 1:1:1 ratio are adequate, such as 10-10-10 or 20-20-20. Follow product label directions for proper dosages; dilute the fertilizer dosage in half if you are worried about burning the fern leaves or think the fertilizer formulation overly rich in nutrients. Spraying or dousing the staghorn fern with fertilizer solution once a month suffices, as part of a typical watering. Allow liquids to fully drip away from the staghorn fern, just as would happen if in a tropical deluge in the rain forest.
  
  

Growth Insight

• Staghorn ferns are not fast-growing, so there's no need to overfertilize or think adding numerous banana peels really benefits the plants. The main concern for good health is lots of warmth -- no temperatures below 50 F -- and high ambient humidity. Douse plants with room-temperature water twice a week during summer but only once every 10 to 14 days in winter. If well-maintained and occasionally fertilized, staghorn ferns sprout new leaves that persist for some time, creating larger and more impressive specimens.