Empty cart
Oh no! It appears your cart is empty. Add some almonds to your daily regime with the Treehouse products.
All Blog PostsNews
Quick Answer
Hull split is the stage in late summer when the outer green hull of the almond cracks open, exposing the shell to air so the nut can dry and mature. It typically begins mid-July to mid-August and is a critical, vulnerable period for farmers, since the exposed shell is susceptible to pests like the navel orangeworm and fungal hull rot. Almonds are ready for harvest once 95-100% of the hulls have split.
From Bloom to Fruit Formation
After a period of dormancy and nutrient restoration during the winter, almond trees erupt in stunning light pink and white blooms sometime between late February and early March. Soon after, those blossoms fall and the almonds begin to form on the branches of the tree.
Throughout the spring and early summer months, almonds on the tree look very little like the nuts we purchase at the grocery store. The lightly fuzzy, oval green pods consist of the outer hull with the almond shell surrounding the nut hidden deep inside. The shell and nut inside the hull must be exposed to the environment to become the familiar brown skinned almond that is eaten and used in food processing.
What Happens During Hull Split
The changes that occur to the hull, called hull split, don’t begin until mid-July to mid-August. The first signs of hull split appear as a crease and slight separation in the side of the green almond hull. As the weeks go by, that crease will become deeper until there is a visible split in the hull, usually about a half-inch wide, exposing the brown almond shell inside.
The hull split allows air to dry the almond. Eventually the hull opens completely. During the split process, the green hull turns to brown, peels away from the nut shell and shrivels as it dries.
Why Hull Split Matters for Pest and Disease Management
Hull split is a critical time for almond farmers. When the shell of the delicate nut inside the hull is put into contact with its environment, this means that it is vulnerable to common pests like the navel orangeworm and to fungi that can cause hull rot. Estimating the timing of hull split is an important part of the growing process.
When Are Almonds Ready for Harvest
Fruit does not always ripen at the same rate which means hulls can split at different times. Once 95 to 100 percent of the hulls have split the almonds are ready for harvest.
References
University of California Ag and Natural Resources: https://ipm.ucanr.edu/PMG/C003/m003fchullsplit.html
California Almond Board: https://www.almonds.org/why-almonds/growing-good/almond-lifecycle
FAQ
WHAT IS HULL SPLIT IN ALMONDS?
Hull split is when the outer green hull surrounding the almond shell cracks open, allowing air to reach and dry the shell and nut inside. The hull gradually turns brown, peels away, and shrivels as it dries.
WHEN DOES HULL SPLIT TYPICALLY OCCUR?
Hull split usually begins between mid-July and mid-August, after the almond forms in spring and develops through the early summer months.
WHY IS HULL SPLIT A CRITICAL TIME FOR ALMOND FARMERS?
Once the shell is exposed through hull split, it becomes vulnerable to pests like the navel orangeworm and to fungi that cause hull rot, making this a critical period for pest and disease management.
HOW DO FARMERS KNOW WHEN ALMONDS ARE READY FOR HARVEST?
Farmers monitor the percentage of hulls that have split; almonds are considered ready for harvest once 95 to 100 percent of the hulls have split, since fruit doesn't always ripen at the same rate.
WHAT HAPPENS TO THE ALMOND HULL BEFORE IT SPLITS?
Throughout spring and early summer, the almond looks like a lightly fuzzy, oval green pod, with the shell and nut hidden deep inside the hull, invisible until hull split begins.
WHERE CAN I LEARN MORE ABOUT THE ALMOND HULL SPLIT PROCESS?
Additional detail is available from University of California Ag and Natural Resources and the California Almond Board's Almond Lifecycle resource.