The almond fruit is the seed of the Prunus dulcis tree, botanically classified as a drupe rather than a true nut. Like peaches and cherries, the almond develops inside a fleshy outer covering that is discarded. Understanding the fruit’s developmental stages is important for maximizing harvest quality. Harvest timing is dictated by natural maturation, which signals when the kernel inside has dried and cured on the tree.
Identifying Harvest Readiness
The single most reliable indicator that an almond is ready for picking is “hull split.” This occurs when the leathery, gray-green outer hull begins to crack open along its suture line, often appearing as a deep “V” shape at the tip. This split marks the beginning of the nut’s final drying phase.
As the kernel matures, it swells and pushes against the hull, causing it to split completely and curl away. The hull’s color changes from green to pale yellow or light brown as it dries. This opening exposes the hard, woody shell beneath, which should also appear dry and light brown.
Ripening is not uniform; nuts in the upper canopy, especially on the southwest side, typically split first due to greater sunlight exposure. For a quality harvest, wait until 95 to 100 percent of the hulls have visibly split. Harvesting too early results in immature nuts that are difficult to process. Delaying too long increases the risk of pest damage from insects like the navel orangeworm, which are attracted to the split hull.
The Physical Harvesting Process
Once the hulls have fully split and the shells are exposed, the physical process of removing the almonds begins. This requires gently dislodging the nuts so they fall to the ground. Before starting, prepare the area by spreading clean tarps or nets directly beneath the tree canopy to catch the falling nuts.
For home gardeners or smaller orchards, a common method is to use a long pole or stick to tap or gently knock the main branches. This mechanical action breaks the abscission layer between the stem and the fruit, causing the ready almonds to drop onto the ground cloth. This technique mimics the large, mechanical shakers used commercially.
Using a tarp prevents the nuts from falling directly onto the soil, which introduces contamination, debris, and moisture. The goal is to collect the almonds quickly and cleanly, minimizing exposure to spoilage factors. After shaking, the collected nuts, still encased in their split hulls, are gathered from the tarp edges.
Post-Harvest Processing and Drying
After collection, the immediate next step is hulling: removing the dry, leathery outer casing. Even though the hull has split, it often remains loosely attached and must be physically separated. This process is necessary because leaving the hull attached after harvest negatively affects the kernel’s quality.
Following hulling, the nuts must undergo thorough drying, or curing, to reduce their moisture content significantly. The goal is to lower the kernel’s moisture level to 6 to 8 percent. This prevents mold growth, rancidity, and the development of aflatoxins during storage. Improperly dried nuts will quickly spoil.
To cure the almonds, spread them in a single, thin layer on a clean surface or screen in a warm, dry area with ample air circulation. This location must be shaded or covered to protect the nuts from rain, dew, and direct sunlight. Drying can take several days to a week, depending on temperature and humidity. A simple test for dryness is shaking a handful of nuts; a fully cured nut will rattle inside its shell. The kernel should also be brittle and snap cleanly when bent, rather than feeling chewy or rubbery.