The best palm tree fertilizer typically involves choosing a fertilizer with a 2-1-2 or 2-1-3 nitrogen, phosphorous, potassium (N-P-K) ratio. While other fertilizers may work fairly well for palm trees, fertilizers with these ratios give the tree the best chance at being healthy longer. If a tree is showing signs of nutrient deficiency, then switching to a fertilizer specific for palm trees is important. Failing to use a palm tree fertilizer in such a case could lead to big problems.

Nitrogen is especially useful for palms, especially potted palms that have a great deal of green in proportion to the rest of the plant. Nitrogen aids in the transfer of energy and is a part of chlorophyll, which is vital to the photosynthesis process. Like most fertilizers, a fertilizer for palms will include nitrogen. Signs of a nitrogen deficiency in palm trees include slower growth, as well as lighter green leaves than the palm normally would have.

While nitrogen is necessary, palms that suffer from lack of potassium are often more at risk for long-term problems. That is why choosing a palm tree fertilizer that has more potassium is recommended. For palm tree owners using a general-use fertilizer, the potassium content may not be enough to truly help the tree. Yellowed to brown older fronds could represent a potassium deficiency, which could take two years or more to completely correct, or could be fatal to the tree if not corrected. Choosing the right palm tree fertilizer will help avoid this situation.

Phosphorous, while also a vital component in photosynthesis, is typically not a big problem for palm trees. That is why most palm tree fertilizers do not have as much phosphorous as they do nitrogen and potassium. It is not good to totally deprive the tree of phosphorous, but the best palm tree fertilizer will focus on those other nutrients.

One of the other important ingredients in a good palm tree fertilizer is magnesium. In fact, if a grower is trying to correct a potassium deficiency, then magnesium becomes even more important. As potassium is added, the tree can become deficient in magnesium. A good fertilizer for palm trees will have 1 to 3 percent magnesium. While this condition is rarely fatal, it will make the palm look unhealthy.

Growers may also prefer choosing an organic palm tree fertilizer rather than a chemical palm tree fertilizer. This is a personal preference and typically makes no difference to the palm tree. No matter which fertilizer is used, choosing one that has a 2-1-2 or 2-1-3 ratio is the most important criterion.