Fertilizing Satsuma

Fertilizer Requirements

• At a minimum, satsumas require nitrogen fertilizer to grow and fruit well, though other important nutrients may be sufficient in good garden soils. Many garden centers sell fertilizers formulated specifically for citrus, making it easy to provide the right blend of nutrients for satsumas. Otherwise, a balanced tree and shrub fertilizer is best, especially if it contains micronutrients in addition to nitrogen, potassium and phosphorus -- the primary plant nutrients that are represented on the label of all fertilizers with three numbers indicating their percentages in the product. An 8-8-8 or 10-10-10 fertilizer is best for satsumas. Satsumas should only be fertilized between Feb. 15 and Aug. 1 so that all tender growth can harden before there is any chance of freezing weather.

Application Rates

• For new plantings, apply 1/6 of a pound of fertilizer about four to six weeks after planting. This can be repeated every six to eight weeks during the growing season, adding an additional 1/6 pound of fertilizer at each application to keep up with the demands of the growing tree, up to 1/2 pound at the end of the season. In year two, begin with a 1/2 pound and again increase the rate by 1/6 pound with each application to a maximum of 1 pound. In year three, continue with the same pattern until topping out at 1-1/2 pounds per application. Continue at this rate for the mature trees, applying the fertilizer three or four times a year.

Container Growing

• When grown in containers, satsumas will need virtually all of their nutrient requirements to be met by the fertilizer. The potting soil provides some nutrients at first, but these are mostly leached away after the first growing season. Use a complete and balanced fertilizer labeled for citrus, though products labeled for acid-loving plants will also work well. For container plants, use half the recommended application rate listed for the product. With limited root space, satsumas will grow more slowly and stay smaller and excessive fertilizer will harm the plant.

Supplemental Nutrients

• Iron and zinc are the two most common nutrient deficiencies in satsumas. Iron deficiency is evident by yellow leaves with contrasting green veins. Zinc deficiency shows a similar characteristic in the leaf, but the green area is in a variable shape all around the veins of the leaf, with the remaining leaf areas having a whitish or yellow color. Commonly available fertilizer supplements can correct these deficiencies; apply iron sulfate or zinc sulfate to the soil, as necessary, until the symptoms disappear.