"My main ambition as a gardener is to water my orange trees with gin, then all I have to do is squeeze the juice into a glass"

Here in the very hot and dry Inland Empire grapefruits, blood oranges and Washington navel oranges perform better than limes, lemons, and kumquats which do better along the coast.   

Location & Planting:  Citrus trees love sunlight and nutrients!  Therefore they need to be planted in a well-drained, full sun location.  As with all trees when planting  dig a hole twice as wide and six inches deeper than your tree’s root ball, then backfill under and around the root ball with a mixture of compost, perlite and native soil.  You want to make sure the root ball ends up sitting level with the soil line. It’s very important that the mixture drains well, so if your native soil contains heavy clay, be sure to blend the compost in well to break up large clumps, I even put some sand to help break up the clay.  Then make a basin around the tree that diverts water toward the roots and away from the trunk.

Watering:   Water your newly-planted citrus tree deeply and thoroughly by filling the basin, allowing it to drain, and filling it again until no bubbles are arising from the soil.. After this initial watering, you’ll want to allow the soil to dry out slightly before watering again. Proper watering frequency is one of the trickiest parts of learning how to care for citrus trees; in the Inland Empire heat, it can be difficult to know how dry is too dry. In general, deep watering once or twice per week should be enough.  Its best to avoid using spray heads that can wet the trunk, which might invite disease. To help retain the moisture and block weeds cover the soil with a couple inches of hardwood mulch. 

Feeding:  Citrus trees are big eaters and should be fertilized monthly from February to September.  The best fertilize for citrus trees are organic fertilizer blend that contains trace  micronutrients like iron, zinc, and magnesium.  Follow the instructions on the packaging for appropriate application instructions.  

Pest and Diseases 

• Leaf Miner. This is the larval stage of a flying insect which lays its eggs inside the leaf of new growth on citrus trees. When the egg hatches, the leaf miner feeds on the leaf as it mines between the layers of the leaf before going into its next stage of development.   Treatment: This insect is NOT very detrimental to the health or production of fruit for this plant. If you are concerned about the appearance, spray with an organic spray or use Neem oil mix on a weekly basis starting at the first sign of new growth. You can also use sticky traps that attract and contain the moths that produce the leaf miner. 
• Whitefly, Scale, Mealybug, Aphids, Psyllids. If you see any of these pests on your citrus, it is most likely due the plant having been stressed for some reason. Most common reasons for stress: ▪ The plant has not been watered as thoroughly as needed. ▪ The plant is in the wrong place with too little sun or poor drainage. ▪ The soil has been depleted of organic matter and nutrients.  Treatment: Spray with Neem, Safer Soap, or other safe spray, if necessary. Strengthen the tree with this “sick tree treatment”: Scratch greensand into the soil, apply a liquid seaweed product  and top-dress with compost. 
• Black Sooty Mold. This fungus occurs in concert with the pests listed directly above, as these pests release a sticky honey-dew that attracts the mold.  Treatment: Treat for insects as above.