Do macadamia trees need a lot of water?
Written by
Olivia Mitchell
Reviewed by
Prof. Martin Thorne, Ph.D.To successfully cultivate macadamia trees, you'll need to become adept at managing water. While young trees will need water each week to establish roots - about 20 gallons - mature trees will survive in the short run without water in near drought conditions. Imbalances in moisture available to the trees can lead to the trees dying from watering too much or too little. Mostly the orchards along the coasts of Hawaii do well with what rains during the year, but producers in mainland areas will often irrigate.
Young Trees (1-3 years)
- Water frequency: 3x weekly in dry seasons
- Volume: 5-7 gallons per session
- Signs of overwatering: Yellow leaves, mold on trunk
Mature Trees (4+ years)
- Drought tolerance: 3-4 weeks without rain
- Dry spell irrigation: 30 gallons biweekly
- Soil check: Probe 6 inches deep before watering
Install drip irrigation for accurate watering. Soaker hoses lose about 40% more water from evaporation compared to drip lines. One farm in Central California reduced its water use by 30% with drip lines. Water early in the morning to reduce fungal disease, and avoid watering in the evening as moisture at night increases the chance of pathogens.
Soil drainage determines what can live in the soil. Improve drainage in clay soils by incorporating 30% coarse sand and 20% perlite. In places with heavy rain, raised beds help prevent root rot plants experience. A grower in Florida reported that he saved 15 trees by making berms after seeing that seine of his trees was stunted due to soggy soil moisture.
Mulch helps conserve moisture without causing the soil to get saturated. Use wood chips and apply 3 to 4 inches of the wood chips around the base of the tree, taking care not to pile it up to, or over, the trunk. Make sure to remove and refresh the mulch at least once a year, as compacted mulch layers can easily trap moisture. Having an old, decomposed layer of mulch is the reason 12 trees developed the disease Phytophthora in Georgia.
Adapt to climate extremes. In zone 9, Arizona, scale up water use for double summer watering, and discontinue once monsoons begin. Floridians usually cease irrigation in the summer due to the rainy season. It's always a great idea to test soil moisture before applying water and even a simple moisture meter takes the guesswork out of it. Trees that are over-watered will take a long time to recover - or may not recover at all - and generally lose a year's production.
Read the full article: How to Grow Macadamia Trees: A Complete Care Guide
