Expert gardener’s tips:
- Cashew trees also grow their own edible — and very juicy — “apples.” They’re actually the nuts’ swollen stalks.
- Cashew shells contain poisonous oil that severely blisters skin. Always handle them with gloves.
Climate
Cashews grow where:
- Temperatures stay above freezing, and preferably above 50°F (10°C). In the U.S., they’re suitable only for USDA plant hardiness zones 10b through 12.
- Annual rainfall measures at least 39.4 Inches (1000 mm). For the heaviest harvests, 60 to 78 inches (1500 to 2000 mm) is much better.
- The dry season lasts from harvest through the following year’s bloom.
Expert gardener’s tip: Dry, sunny weather during harvest prevents the fallen nuts from decaying or sprouting. During flowering, it prevents fungal outbreaks.
Growing Cashews
Cashews need a planting site with at least six hours of daily sun. They handle most well-draining soils but really flourish in rapidly draining, sandy loam. Too much water kills their roots. Allow from 23 to 29 feet (7 to 9 meters) between trees and 15 to 20 feet between the trees and structures or power lines.
Watering
Water a newly planted cashew tree every two days for the first week and then once or twice weekly for the next two months. Over the next three years, water it weekly only when you’ve gone five days or longer without rain.
Watering fruit-bearing cashews only during very long dry spells in spring or summer. To prevent waterlogging, water them slowly and deeply with a soaker hose or drip system.
Expert gardener’s tip: Retain soil moisture around the trees with a 2- to 4-inch layer of organic material such as shredded bark. Keep it at least 8 inches away from the trunks.
Fertilizing
Fertilize cashews organically with well-aged, pasture-raised chicken or cow manure. Once a year when the soil is wet, dig a circular trench 10 inches wide and 6 inches deep, 5 feet from the base of the trunks. Spread the manure evenly in the trench, but don’t water it in.
Pruning
After its first few harvests, prune some of a cashew’s upper branches back to their crotches to let more sunlight reach the lower canopy. Pruning also reduces the labor involved in harvesting and limits the risk of storm damage. Time the job for right after harvest.
