Q. Why are the leaves on my orange tree turning yellow?
Lack of fertilizer or using the wrong type of fertilizer could be causing your tree's leaves to turn yellow. At a garden center, look for a fertilizer formulated specifically for the needs of citrus plants. The nutrient ratio might be something like 19-6-12 or 12-2-6.
Basically the nitrogen (N), which is the first number, should be higher than the other two, phosphorous (P) and potassium (K). If you can't find a citrus-specific fertilizer, try to find one where the N is twice as much as the P and the K, for example 10-5-5 or 20-10-10. The exact number is not as important as the ratio between the nutrients.
Also make sure that the fertilizer you choose contains micronutrients such as iron, copper, calcium and sulfur. And of course, follow the directions on the package when applying the fertilizer.
See SFGate's How to Fertilize Citrus Container Plants for further information.
For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service