Palm Tree Fertilization
Palm trees can be found across a wide, arcing swath of the U.S. from Virginia to Florida, west to California and north to Washington, and across the border in British Columbia. Palms mostly grow in hardiness Zone 8 and above, and will also successfully grow in microclimates, even in Zone 7.
Palm trees Thrive in Nutrient-rich Soil
Palm trees require a wide variety of essential nutrients for them to remain healthy, particularly: nitrogen (N); phosphorus (P); potassium (K); and, magnesium (Mg). Palm trees also require a number of micronutrients, including: boron (B); calcium (Ca); copper (Cu); iron (Fe); manganese (Mn); and, zinc (Zn).
The wide variety of nutrients palm trees require and the poor, nutrient-deficient sandy soil in which they often grow, make a routine fertilization program very important. Nutrient deficiencies can cause a wide range of diseases in palm trees, but with proper fertilization and care, these diseases can be avoided. Check with your local university extension to learn more about the common nutrient deficiencies in your area and to have your soil tested for specific nutrient deficiencies in your soil.
In addition to not providing the correct nutrients, it’s also important that the correct amount of nutrients is applied—too much or the incorrect proportions of nutrients can be more detrimental to palm trees than not fertilizing at all. Turf fertilizers, for example, should never be applied to palms or used near them. Soil conditions and pH level are also considerations.
Slow-release Fertilizers are Best for Palm Trees
Milorganite is a slow-release fertilizer that works for up to ten weeks and its organic matter helps condition the soil to better hold moisture. Quick-release, artificially coated fertilizers release nutrients too quickly for palms to fully benefit from them and can easily wash away after only a few rains.
Fertilizing Palm Trees with Milorganite
Milorganite, with the addition of potassium and micronutrients, can be the basis of a complete palm tree fertilization program. Palm trees should be fertilized four times, evenly scheduled throughout the growing season in your area of the country, which may be as early as March and as late as October. Apply 5–10 lbs. of Milorganite by broadcasting it evenly under the entire canopy of the palm. Stay two feet from the tender trunk of the palm tree.
Signs of potassium deficiencies—the most common nutritional deficiency seen in palm trees—vary among species, but always first appears on older leaves and may include yellow spotting, yellow tips, and withered or frizzled leaves. Potassium should be applied in addition to Milorganite for a more complete palm tree fertilization program.
Light-green, older palm tree leaves, and eventually the younger leaves, are a tell-tale sign of nitrogen deficiency. Regular applications of slow-release, nitrogen-rich Milorganite during the growing season can help prevent the problem, or quickly and easily correct this deficiency if you’re already seeing signs.
If young palm tree leaves show uniform “chlorosis”—an absence of normal green color—it’s showing signs of iron deficiency, and the lack of color will eventually spread to the older leaves. This is a sign of iron deficiency and may also indicate poor soil aeration. Milorganite contains 2.5 percent organically complex, non-staining iron and can help prevent and alleviate iron deficiencies.
Palm Trees are Sensitive and Should to Treated with Care
Palm trees, in addition to being voracious eaters, are sensitive. If a palm is punctured or damaged using a string weed trimmer, for example, the wounds never heal. Palm trees are also susceptible to chemical burns from quick-release fertilizers. Both make palm trees more susceptible to diseases. Milorganite is non-burning and much safer to use to fertilize palm trees.