Most gardeners will encounter browning fronds on their palm trees at one point or another. Older leaves have a natural tendency to turn brown and shed away — this is completely normal. An overabundance of fertilizer can cause the tips of fronds to turn brown. This is prevented by only applying fertilizer during active periods of growth. Fronds may also turn brown during periods of extreme temperatures, so they may require some form of protection at these times. Under-watering will cause the entire plant to turn brown. Always water thoroughly and check the soil moisture frequently.