Can macadamia trees grow in the United States?
Written by
Olivia Mitchell
Reviewed by
Prof. Martin Thorne, Ph.D.Growing macadamia trees in the U.S. depends on duplicating subtropical conditions. The trees grow best in Hawaii, Southern California, and Florida, as long as they are not going to experience winter temperatures below 25°F (-4°C). Frost will damage the flowers and nuts, so it is crucial to comply with the zone. Greenhouses can help in regions of the country that are experiencing cooler conditions.
Optimal Growing Regions
- Hawaii: Volcanic soils, 120+ inches annual rain
- Southern California: Coastal fog buffers heat
- Florida: High humidity, spaced plantings
- Greenhouses: Extend range to zone 8 with heating
Climate Requirements
- Temperature: 50-85°F (10-29°C) year-round
- Rainfall: 50+ inches or drip irrigation
- Humidity: 60-80% prevents husk cracking
Soil and spacing determine survival. You should plant into well-drained soil with pH 5.5-6.5. For heavy clay soils in Florida, you will want to mix in 30 percent perlite. Space trees 30-50 feet apart, a cramp Florida farm had, over 40 percent root competition loss until they spaced trees out to 45 feet.
Greenhouse cultivation requires exacting precision. Maintaining 70-85°F (21-29°C) with 60% humidity is achieved by using misters. Full-spectrum LED lights should be used for a 12-hour light cycle. A nursery in San Diego is successfully growing 50 lbs/tree indoors, comparable to what Hawaiian orchards produce. Hand pollination with a brush is a reliable procedure to help set nuts.
Cross-pollination increases production even in a glass house! Use Beaumont with James cultivars to yield results. A location in Michigan doubled production utilizing these two cultivars. Like droopy flowers, without partners, flowers drop early. Bees do not perform effectively in an indoor environment, so every morning at bloom time, you must hand-pollinate your crop.
Read the full article: How to Grow Macadamia Trees: A Complete Care Guide
