The Proper pH for Palm Trees
In addition to regular fertilizing and occasional watering, queen palms need soil with the correct pH to ensure healthy growth and prevent nutritional deficiencies.
Importance of pH
Soils are acidic, alkaline or neutral. These conditions are determined by the pH level of the soil. Neutral soils have a pH of 7, while acidic soils are below 7 and alkaline soils are above 7. The basic pH of soil comes from its composition, such as sand-based or loam-based, and is affected by fertilizers and rainfall. Incorrect pH levels can cause nutritional deficiencies in queen palms by preventing nutrient uptake. Low pH levels can cause calcium, phosphorus and magnesium deficiencies. High pH level can cause nitrogen, iron and manganese deficiencies.
Symptoms of Nutritional Deficiencies
Queen palms show most nutritional deficiencies in their leaves. These deficiencies may be the result of either lack of fertilizer or incorrect soil pH levels limiting the uptake of available nutrients. Nitrogen deficiency shows first with a yellowing of older leaves. If the deficiency is not corrected, the entire canopy of the queen palm will yellow and the palm’s growth will slow. Symptoms of potassium deficiency include yellow spots on the leaves and dead leaf tips, or frizzle. Queen palms with a magnesium deficiency have yellow leaves with green spines. New leaves that are yellow with necrotic streaks point to a manganese deficiency.
Queen palms need a soil pH level between 6.2 and 7.6. The soil should drain well but be able to hold sufficient moisture between waterings. It is important to remember that the pH of the soil cannot be determined by the condition of the tree; the only reliable way to determine the soil’s pH level is to test the soil. Hand-held soil pH testers are available at many garden stores. Alternatively, many county extension offices offer soil testing. You will need to collect soil samples around the queen palm, or at the planned planting site, and take them in to have them tested.
Amending the Soil
Highly acidic or alkaline soils will need amending if you want your palm tree to thrive. Agricultural lime increases pH levels, although it can take up to a month for it to neutralize the soil. Wood ashes also increase pH levels. The ashes are used only on the soil surface, as they can damage roots if they are worked into the soil. To lower pH levels instantly, work aluminum sulfate into the soil. Working compost into the soil corrects both high and low pH levels. You can work compost into the soil before planting palm trees, or you can work it into the topsoil of established plantings.