Staghorn ferns are a tropical plant that need to have diffuse light and even moisture. In the St Louis area that means bringing the ferns indoors when temperatures fall below 50F and placing outdoors in a partially sunny space during warmer weather. The frond structure of the ferns will funnel water towards the roots when rain fall happens however the ferns will need to be hand watered about once a week when actively growing. Adding a water soluble fertilizer once a month during warm weather will keep the fronds healthy. No need to add fertilizer during the winter months or when the ferns are growing slowly. If you notice brown patches on the undersides of the fronds, this is a sign of a healthy plant. These are spores being formed by the ferns.