Citrus is a variety of shrub that produces acidic fruit in the cooler winter months in warm climates. Citrus trees prefer a sandy soil that drains well and require great care with watering and feeding. Citrus trees are heavy feeders and require nutrients consistently throughout the year to produce the best and greatest amount of fruit.
Fertilize annually with an equal amount of nitrogen, phosphorus and potassium. You can find these nutrients in a standard balanced, or 10-10-10 fertilizer. Slow-releasing standard fertilizer is more beneficial for citrus because it ensures the nitrogen does not wash below the root line. Apply and water standard fertilizer in annually.
Supplement annually with additional nutrients including magnesium, boron, copper and zinc. These trace elements are found in turf fertilizers. Just as with the balanced fertilizer, apply and water these nutrients in annually.
Incorporate mycorrhizal fungu into the soil. Mycorrhizal Fungus attaches to a plant's root system and enables the roots to absorb more nutrients from the soil. This fungus tends to be absent from most urban soils.
Test the soil annually. Add iron supplement tablets if the soil is above a pH of 7.
Incorporate mycorrhizal fungus into the soil annually beginning two planting seasons before planting the citrus tree.
Incorporate fish emulsion fertilizer into the soil biannually beginning one planting season before planting the citrus tree. For best results, fertilize initially in the spring as the tree is budding, and again after you have harvested its fruit.
Mix 5 cups of hot water with 1 pound of coffee grounds and let the mixture sit overnight. Pour the coffee water onto the tree's root system annually at the start of spring for added soil acidity. For best results, apply at night and water in well.