How often you water depends almost entirely on the tree's age. A newly planted mango drinks every other day at first, while a mature one might go weeks without a drop. Watering a mango tree less as it grows older is the whole game, so the frequency drops sharply over the first few years.
I planted a grafted Carrie mango here in coastal Zone 10A South Florida, and one rainy summer it pushed soft, yellow leaves. I had it on a fixed every-three-days schedule, and the storms kept dumping rain on top of that. The soil under it never got a chance to dry. I dug down with my hand and the dirt was wet and heavy three inches deep. So I backed off to deep soakings spaced a week or more apart, and I skipped watering after storms. Within a month the new growth came back firm and green. The roots wanted to dry out between drinks.
Here is the reason behind that. Mango roots need oxygen to work, and soil that stays soaked all the time pushes the air out. The roots start to suffocate. That wet, airless soil is exactly where root rot takes hold. So deep but infrequent watering beats frequent shallow watering. A deep soak wets the full root zone. Then the soil dries and lets the roots breathe before the next round, which is what keeps them alive and growing.
Your mango watering schedule should track the tree's stage, not the calendar. UF/IFAS guide MG216 and Texas A&M AgriLife lay it out by age. Newly planted trees get water every other day the first week, then 1 to 2 times weekly. From years one through three, plan on about once weekly during dry spells. A mature tree needs water only during prolonged dry periods, with deep weekly soakings through a hot, rainless summer.
Before you turn on the hose, check the soil a few inches down with your finger. If it feels damp at that depth, wait and check again the next day. This one habit saves more of your trees than any schedule, because it tells you what your tree actually has instead of what you assume. Your goal is moist soil, not wet soil. Skip a planned watering after heavy rain too, since the ground around your tree is already full. When you do water, give the root zone a long, slow drink so the moisture reaches deep where your tree feeds.
Water at the base of the tree, not the leaves, using a drip line or soaker hose so the water sinks straight to the roots. Then lay down a ring of mulch to hold that moisture in the soil between waterings. Keep the mulch pulled back a few inches from the trunk, since piling it against the bark traps damp air and invites rot at the worst spot.
The biggest mistake I see is an overwatering mango tree habit. People water on a fixed day no matter what the sky did that week. Mango decline from soggy roots is far more common than damage from drought. So lean dry. Let the soil dry between drinks. Water deep when you do, and watch the tree instead of the calendar. A healthy mango will need you far less than you think, and it will tell you when it is thirsty long before it suffers.
Read the full article: Mango Tree Care: A Complete Grower Guide
