California in Full Bloom

2/26/20 – an update by Agronomist Zac Ellis

When did full bloom occur?

The Northern/Central Valley full bloom was on February 22nd and the Southern Valley bloom was on February 23rd   - earlier than anticipated.

How is progression of the pollinator varieties vs Nonpareil?

Depends on the pollinator, but Sonoras, Ne Plus and Avalons are way ahead of Nonpareils, whereas Montereys, Buttes and other hard-shell varieties were a couple days behind.

How is the weather looking for the next 2 weeks?

The weather looks favorable, while some rain is in the forecast, but not enough to be worried about state wide.

How is the general yield expectation as compared to last year?

The yield potential is good, which is slightly better in the north than the south compared to last year.  The productions levels are high in the south and subsequently low production levels in the north. The bloom weather and effective pollination overlap has been great, with bee flight hours optimal.  Now that bloom has started, it is moving rapidly, but bee flight is good and this flash bloom isn’t expected to have much of a negative effect.

What do you think is the science behind yield?

As per UC Davis Carbohydrate Observatory’s findings, the non-structural carbohydrate (NSC) production is most correlated to yield in October twig and bark samples of the prior year. 2019 NSC production and storage is overall similar to the last season; with a slight shift in more NSC storage in the wood and less in the bark. Wood NSC storage is also most strongly correlated to yield potential. In other words, our carbohydrate levels have what it takes to make a good crop overall, even with the larger production we experienced in 2019.

What is a flash bloom?

A flash bloom is when almond bloom starts and ends rapidly, much like this season. If weather is not favorable during a flash bloom, the effects could be negative. However, if there is consistent warm and dry weather during bloom, bees usually manage to get the job done despite a quick bloom period.

Did weather in early February slow the bloom?

Bloom weather started to warm up in late January, which caused the early almond varieties to start to open up. However, the weather took a dip in night-time lows in early February. Although daytime highs were still above average, night-time lows kept bloom at bay until the third week of February.  A spike in night-time lows February 22nd was the catalyst for bloom across much of the valley and rapidly developed into full flowering.


Zac Ellis is the Senior Agronomist for Olam's California treenut operations.  He has spent the last 3+ years managing all agronomic and technical services for 13,000+ acres of almonds, walnuts, and pistachios in our California orchards.  A graduate of Cal Poly San Luis Obispo and California State University, Fresno, he has bachelor's degrees in agribusiness, PCA / Plant Science, and a master's degree in Plant Sciences.