Good Fertilizer for Lemon Trees

Lemon trees are thought to have originated in India and spread to the Mediterranean. Columbus and other early Spanish explorers probably introduced lemons to the Americas. Until recently, lemon trees were only grown in warm, southern climates, such as Florida, California and Arizona. The least cold resistant of all citrus, they are nipped or even killed when temperatures dip below 28 degrees Fahrenheit. Since the introduction of an improved, disease-free Meyer lemon tree, northern growers can grow lemons indoors in containers. A regular watering and fertilizing program will keep them healthy.

Varieties

True lemons, such as Eureka and Lisbon grow commercially and in home gardens throughout the southern United States. These are the lemon varieties most often available at grocery stores. Ponderosa lemons produce large, seedy fruit with thick skins. Meyer lemons are thin-skinned and round, with sweet juice. The trees are often grafted to dwarf rootstock, making them a good choice for container growing. Meyer lemons are more cold-resistant than other varieties.

Fertilizer Types

Fertilizers for lemons are typically granular, slow-release formulas. They are sometimes labeled as citrus fertilizers, although growers may use any formula with the appropriate nutrient content. Ammonia sulfate (21-0-0) is a good formula for most home growers, according to Texas A&M University Extension. Container-grown Meyer lemons may benefit from the application of an acidic fertilizer or one specifically labeled for citrus, advises Oregon State University Extension.

Methods

Fertilize lemons when they are most actively producing fruit--usually late fall to early spring. Apply fertilizer in equal amounts in February, May and September. Wait to fertilize newly planted lemon trees, says Texas A&M University Extension, until new growth emerges. Then apply, 1 cup ammonium sulfate divided into three separate feedings. As the tree matures, increase the amount of fertilizer applied annually by 1 cup per year of the tree, for a maximum of 10 lbs.

Considerations

The amount and type of fertilizer to use depends, in part, on the grower's goals. Commercial growers in Florida typically apply equal amounts of nitrogen and potash to lemon trees. Increased nitrogen results in higher yields and more peel oil content, according to Purdue University, but also contributes to scab infections. High amounts of potash increase the acidity of the fruit.

Growing Conditions

Lemons need a sunny location, protected from chilly temperatures. A south-facing location near a building or other trees is ideal. All lemons need a well-draining, loamy soil, according to Texas A&M University. Container-grown lemons in the north spend summers outdoors, but are brought inside before the first frost. These lemons need a bright, sunny window to thrive.