Short answer: water citrus deeply (about 2 feet down) and out past the edge of the canopy, let the top 6 inches of soil dry between waterings, feed three times a year, prune very little, keep the low "skirt" of branches, and cover lemons and limes on frosty nights.
How to water citrus
- Water deep and wide. Wet the soil from the trunk to just past the drip line, at least 2 feet deep.
- Let it dry a little. Let the top 6 inches dry before watering again. Frequent shallow watering misses roots and builds up salt.
- Use enough emitters. A mature tree needs about 2 to 6 drip emitters, moved outward as the tree grows. A basin (a 4 to 8 inch berm) should reach about a foot past the canopy. Don't pile soil against the trunk.
- Keep it even. Steady, deep watering helps prevent split fruit.
Citrus watering schedule for the low desert
| Season | Young tree (4 months to 1 year) | Tree 1 to 2 years | Mature tree, 3+ years (basin) |
|---|---|---|---|
| Dec to Feb | every 14 days | every 14 to 21 days | every 21 to 30 days |
| Mar to Apr | every 7 to 10 days | every 10 to 14 days | every 14 to 21 days |
| May to Jun | every 5 to 7 days | every 7 to 10 days | every 14 days |
| Jul to Sep | every 2 to 5 days | every 7 to 10 days | every 10 to 14 days |
| Oct to Nov | every 5 to 10 days | every 10 to 14 days | every 14 to 21 days |
From University of Arizona Extension AZ1151. Mature trees on drip or microsprinklers need the shorter "young tree" intervals. Water more often in sandy soil or extreme heat, less in clay or cool, rainy weather.
When to fertilize citrus in Arizona
- Oranges, tangerines and grapefruit: split the year's fertilizer into three equal feedings in January to February, March to April, and May to June.
- Lemons and limes: January to February, March to April, and August to September.
- How much: the Extension chart ranges from about 0.25 to 0.5 lb of actual nitrogen a year for a small tree to 1.25 to 1.5 lb for a large one. Grapefruit get about half the chart amount; lemons and limes about 10% more. Don't fertilize a newly planted tree until it puts out new growth.
- Water it in. Work fertilizer into the soil and water right after.
Pruning: less is more
- Best time: February through April.
- Avoid: heavy pruning May to mid-October (sunburn risk) and November to January (it pushes tender growth before frost).
- Keep the skirt. Low branches shade the trunk, and the best fruit is often down low.
- Remove sprouts from below the graft and dead or crossing branches.
- Protect exposed bark with white latex paint diluted 50% with water. Never use oil-based paint.
Frost and citrus
Citrus are not very cold hardy, and lemons and limes are the most frost-tender. Cover young and tender trees on frosty nights with frost cloth draped to the ground, wrap young trunks, and keep trees watered. Don't prune frost damage until spring. See how to protect plants from frost in Arizona.
Common citrus problems
- Sunburned fruit or bark on the south and west sides: keep the skirt and paint exposed bark.
- Yellow leaves that drop: often too little nitrogen or too much water.
- Leaves curling inward: usually too little water.
- Split fruit: uneven watering or feeding.
- Fruit dropping early: often hot, dry, windy weather or not enough water.
- Aphids: hose them off, or spray 1 tablespoon of dish soap per gallon of water.
Harvest tip
Many citrus ripen in the cool months, and fruit color isn't always a reliable sign. Taste one fruit before you pick the whole tree.
Need a hand with your trees?
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Find tree servicesFAQ
How often should I water citrus trees in Arizona?
Mature citrus on a basin: about every 21 to 30 days in winter and every 10 to 14 days in summer. Young trees and trees on drip need water more often.
When should I fertilize citrus in Arizona?
Oranges, tangerines and grapefruit in Jan to Feb, Mar to Apr and May to Jun. Lemons and limes in Jan to Feb, Mar to Apr and Aug to Sep.
When is the best time to prune citrus in Arizona?
February through April. Avoid heavy pruning in summer and in late fall and winter.
Are lemon trees frost tender?
Yes. Lemons and limes are among the most frost-tender citrus. Cover them on nights near freezing.
Keep planning
Sources
- University of Arizona Extension: Irrigating Citrus Trees (AZ1151)
- University of Arizona Extension: Citrus Fertilization Chart for Arizona
- University of Arizona Extension: Pruning Citrus
- University of Arizona Extension: Diagnosing Home Citrus Problems
- University of Arizona Extension: Protecting Citrus Trees from Cold
General guidance for the low desert. Your soil, tree age and variety change the details.