Water citrus trees deeply and regularly, adjusting by tree size, age, climate, and soil drainage. A practical summary follows, with typical ranges you can use as a starting point. Direct answer

• Young citrus trees (under about 5 years): water more frequently, aiming for thorough soil wetting to encourage deep roots. In hot, dry summers, this often means about 2 times per week; in milder seasons, once a week can suffice. Each watering should penetrate several inches into the root zone, roughly delivering a total of several gallons per watering depending on tree size and irrigation method. Maintain even moisture without keeping the soil soggy.

• Established citrus trees: water less often but more deeply. During summer, aim for roughly every 1–2 weeks, depending on soil texture and drainage, ensuring the root zone (not the trunk) is wetted well. In cooler months, reduce frequency to once or twice a month, adjusting for rainfall. The emphasis is deep, infrequent irrigation that maintains evenly moist soil.

• Container citrus trees: water when the top of the soil dries out, or is just slightly damp, and ensure excellent drainage. Do not allow the surface to stay dry for extended periods, but avoid keeping the soil constantly soggy.

• General approach: water deeply rather than frequently, and adjust for rainfall, temperature, and soil drainage. Irregular drying and re-wetting can stress the tree, causing leaf drop or other symptoms. If the soil drains slowly or stays wet, adjust downward; if it drains quickly, adjust upward or increase watering depth/duration.

Notes for better accuracy

• Always tailor watering to your specific situation: soil type (sandy, loamy, clay), drainage, pot size (if container-grown), tree size, and local climate. A watering schedule is a starting point, not a universal rule.
• Use slow, deep irrigation (drip systems or soaker hoses are ideal) so water penetrates deeply and doesn’t run off or evaporate quickly. For young trees, routines often specify longer run times to reach deeper roots.

• For mature trees in drought-prone areas, consider irrigation based on actual soil moisture and tree response, rather than a fixed calendar schedule. Signs of under-watering include leaf curling or leaf drop; over-watering signs include yellowing leaves and poor drainage.

If you’d like, share your location, whether the trees are in ground or in pots, and how your soil drains (easy to tell by a simple rain test or shovel test). Then a more precise plan can be outlined, including exact gallons per watering and a week-by-week calendar for your situation.