Yes, macadamia trees need water in large amounts to stay healthy and produce good nuts. Mature trees can use up to 92 gallons (350 liters) per week in hot weather. This high demand makes them thirsty trees that need steady moisture through the whole growing season each year.
The macadamia water requirements change based on tree age and weather patterns. Young trees need the equal of 50 inches of rain spread through the year per NC State research. That works out to about an inch per week if rain doesn't fall in your area often.
I learned to read my trees for signs of water stress over the years of growing them in my yard. Leaves that droop or curl in the afternoon tell you the tree needs more water soon. Yellow leaves at the base can mean too much water and root rot starting below ground.
Watering macadamia trees works best with deep soaking less often rather than light daily sprinkles on the surface. Deep water reaches the root zone where trees can use it for growth. Light surface watering keeps roots near the top where they dry out fast and can't support the tree well.
Water needs jump during fruit set and nut filling stages in the summer and fall months. Queensland research shows this is when trees can hit that 350 liters per week mark for mature specimens. Cutting back water during these key times will hurt your harvest size and nut quality badly.
UC Agriculture suggests drip lines or micro sprinklers work best for getting water to tree roots well. These methods put water right where trees need it without waste. I set up a drip system on timers that runs twice per week during the dry season in my backyard orchard.
Mulch helps cut your macadamia irrigation needs by keeping soil moist longer between waterings. Spread 3 to 4 inches of wood chips or bark mulch around the tree but keep it away from the trunk base. This layer also keeps roots cool and adds nutrients as it breaks down over time.
Check soil moisture before you water by poking a finger a few inches deep near the drip line. Dry soil means time to water your tree soon. Moist soil means you can wait another day or two before watering again. This simple finger test helps you avoid both under and over watering problems.
Read the full article: Growing Macadamia Trees: A Complete Care Plan
