April 12, 2003

Question: We read your column on March 22 with regards to Boron application to Boron deficient pygmy date palms. Would this treatment also benefit queen palms? They appear to be doing well. What other types of plants would benefit from Borax and in what amounts would you recommend?

- RP Smith, e-mail

Answer: Your e-mail will help me clarify some important points relevant to plant Boron (B) requirements and B fertilizer application. Boron is known as a micronutrient, meaning, it is required by plants in very small amounts. As an example, when growing commercial tomatoes in southwest Florida, farmers apply to the crop the equivalent of 8.6, 3.4, and 8.4 pounds of nitrogen, phosphorus, and potassium, per 1000 square feet, respectively, but only one ounce of B for that same area. On a 10'X10' garden site, that’s only about 0.1 ounces of B. Boron applied in excess amounts can damage or even kill plants. Thus, for pygmy date or queen palms having B deficiency, no more than 1 to 2 ounces of 20 Mule Team Borax (soap detergent), or Solubor mixed in 4 to 5 gallons of water and applied to the soil is recommended. This treatment should not be used as a routine B application. A separate B application to plants is usually totally unnecessary and potentially harmful. The best was to prevent B deficiency is to purchase fertilizer with B in it.