Almond Dormancy & Bloom

An Interview with our Senior Agronomist

Olam Farming, Inc. has almond orchards spanning California's Central Valley and our teams are working hard in the leadup to this year's almond bloom, which is rapidly approaching.  We took a moment to sit with our Senior Agronomist, Zac Ellis, to learn a bit more about dormancy, bloom, and all the work that goes on during this busy time of year.

How has winter weather been, leading up to bloom?

We had some good storms come in November and December, giving a fair bit of snowfall in the Sierras. Not much has materialized since, but those storms alone have put us at 75% of the 16-year historical average.

What activity is there on the farms in the leadup to bloom?

Right now, we are busy finishing up our winter dormant sprays for scab and scale, mummy sanitation, pre-emergent herbicide applications and intermittent replanting for trees blown over or dead from last season. We are also replanting about 600 acres of orchards under our redevelopment program.  

How reliable is bloom weather forecasting?

Bloom weather forecasting is mediocre at best, we can only predict a week out with any real accuracy. We are currently collaborating with a company that our counterparts in Australia have trialed to get better microclimate yield prediction capabilities. We are hoping for better accuracy as a result.

How do you determine when the trees will be in full bloom each year?

Bloom timing is a result of both chill accumulations followed by warmth accumulations.  We track the weather and chill hours throughout dormancy and compare it to historical records to create a tentative timeline for an expected bloom.  As for this year's bloom, the weather was relatively like the historical average.  We had met our chill portion requirements in all regions and continued to track throughout the rest of January.  With the weather being a little warmer towards the end of the month, we projected bloom to start during the second week of February on early varieties and the third week for nonpareils.

What is ideal bloom weather for high yield and quality?

Ideal bloom comes when there is consistent weather and a slow ramp up in temperature going into February. If we experience any extreme highs or lows, bloom overlap will be poor. During bloom, we like mild, sunny days with low wind and no precipitation. This will ensure adequate bee flight hours for pollination during the effective pollination period when bloom overlap is at it’s best.

Is there anything we will be doing in case weather is not conducive to bloom?

Not a whole lot, Mother Nature must do the work. All we can really do is ensure that we have high quality bees with a minimum of 8 frames per hive. From a pre-plant perspective, we want to make sure we are planting varieties that have good overlap. We are running some trials on our poorer overlapping early blooming varieties where we graft different early blooming varieties on main scaffolds near our bee drop sites. We are hoping we can help with overlap on the early bloomers by providing a compatible pollen source that will help with cross-pollination.

Where are the Olam orchards? Has bloom weather been different across our orchards in the past?

Olam has farms from North to South in California, spanning ~240 miles from the furthest north to the furthest south. Bloom usually begins in the south and makes its way north, but there have been years where that pattern is flip-flopped because of weather variability within different regions.

What indicators are there post-bloom that the bloom has been successful?

We track bee flight hours, which are a combination of temperature, windspeed and precipitation. We also track bloom overlap and overlay with bee flight hours to see if the bees were active during the effective pollination overlap period. The best indicator is after May when all the fruit is shed that did not get pollinated and fertilized.

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.