Hull Split Timing Crucial for Harvesting Almonds Successfully

After months of watching their orchards go from bud to bloom to nut, the big moment has arrived for almond growers.

It’s hull split time. That means growers will start shaking the nuts off the trees soon.

Field scout Jenna Mayfield reports about 15 percent of hulls are split open in trees. Harvest starts when 95 to 100 of the hulls have split.

Unsplit almond stage. (UC IPM photos)

As we all know, of course, fruit – whether it’s a peach or an almond – doesn’t ripen uniformly. Oh, that would be too easy.

For almonds, hull split usually starts in the upper and outer sections of a tree in the southwest area – where it gets the most sun during the day. The nuts on the top of the tree are the least mature.

Initial separation of hull.

As a result, it’s important for growers to continue monitoring the progress of hull split to protect against pests. Jenna notes growers have been applying hull split sprays to combat bugs such as navel orangeworm (NOW). University of California Integrated Pest Management says NOW applications should be done during the start of hull split and the beginning of egg laying.

Hull at the deep "V" stage.

Peach twig borer and hull rot fungi are other concerns at hull split. Remember, the hulls provide a protective shell and after they split open the nuts are exposed to these bugs. It’s important to harvest the crop as soon as possible to limit pest exposure.

Split of ess than 3/8-inch.

Initial drying stage.

The first thing growers need to do is find out if hull split has started. Sometimes, it’s tricky to see through the foliage and branches. A handy trick is using a pole pruner to cut small branches from the top southwest section of five or six trees to see if hulls are starting to split.

Here are some other tips from UC IPM:

• Continue monitoring trees until 95 to 100 percent of the fruit at eye level are visibly split.

        To determine when to start harvest, growers can hit a tree limb to see how easily the nuts come  off. Then test shake a few more trees. When 99 percent of the nuts are shaken from the test trees then the time is right to start shaking the entire orchard.

Complete drying stage of almond.

• Harvest blocks with poorest sanitation first.

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Historically, shaking starts in early to mid-August. But Jenna has seen in the past growers starting tree shaking as soon as July 25 in the Northern San Joaquin Valley.