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Tips for Growing Healthy Citrus This Fall

Autumn in California is a great time of the year to check your citrus tree to make sure it has the right nutrients necessary to grow healthy before you (quite literally) reap the fruits of your labor. While the seasonality of citrus trees can variate depending on a range of factors like temperature, location, soil type and more, many types of citrus do require maintenance and care throughout the year.

Here are some tips to help your citrus tree grow healthy, starting as early as this fall:

1. FERTILIZING

Apply the recommended amount of fertilizer, including nitrogen, phosphorus and potassium, and cover with compost, then water. Make sure to water heavily if it’s a newly planted tree so the water sinks into the roots. Fertilize throughout the year, but especially during February, May, August and October. If you have a new tree, it’s especially important to fertilize regularly during the first four years.

2. MANAGING PESTS

Pest management is crucial to protect not just your own tree, but also your neighbors’ trees and the state’s citrus. Inspect for a pest called the Asian citrus psyllid (ACP) monthly or whenever watering, spraying or pruning trees and when harvesting fruit. The psyllid can spread the deadly plant disease called Huanglongbing (HLB), and has been found in Orange, Los Angeles and Riverside counties thus far. Once a citrus tree is infected with HLB, there is no cure and the tree will die. HLB affects all citrus plants, including orange, lemon, lime, mandarin, pomello, kumquat, grapefruit and tangerine trees. It also affects some relatives of citrus, like orange jasmine and curry leaf trees. If you have any of these plants in your yard, inspect them for symptoms of ACP when trees have new leaf flush or when tending to trees. You can call a licensed pesticide applicator or treat your citrus trees yourself with insecticides to keep the ACP numbers low. It’s also important to control ants on your citrus tree, as ants may protect harmful pests like the ACP.

If you think you’ve found the ACP or HLB, call the statewide hotline at 800-491-1899. If you are unsure how close you are to an HLB detection or quarantine area, visit the UC Agriculture and Natural Resources’ app where you can enter your address into the search bar and see your proximity to HLB.

3. WATERING

During the first year, apply water at the tree’s trunk. As the tree grows, water a larger area around the tree. Newly planted trees should be watered every three to seven days. Older trees can be watered every week or two.
Citrus trees do not adjust well to colder temperatures, such as 45 degrees Fahrenheit or below. If temperatures do get this low in your area, consider growing a potted citrus tree indoors to keep it from low temperatures. Consult a gardening expert for tips on the best varieties of citrus to grow indoors.

4. HARVESTING

Harvesting time depends on the citrus variety and its seasonality. Take time reviewing the harvest because not all fruits on the same tree may ripen at the same time. In general, you know when they are ready to harvest when they have reached the desired size and ripeness/color. Some citrus can drop from the tree when fully ripe, so check the citrus tree regularly when tending to it to see if it is ready to harvest.

5. PRUNING

Most citrus varieties do not require significant pruning. Lemons are the exception to this rule. Heavy pruning should not take place in winter as it will make trees susceptible to frost damage. Pruning should be done after fruit is harvested so you do not interfere with the fruit’s growth. Remove all dead branches, stems that are weak and small, and shape your tree like a canopy. When pruning, make sure sunlight is evenly distributed on your tree. If you are located where the disease has been found, it is important to double bag leaves/stems and check all pruning materials/equipment for trimmings/debris before moving any plant material from your property.

More info and photos of the Asian citrus psyllid and HLB symptoms are available at www.californiacitrusthreat.org