Early Season Almond Fertilization Strategies 

S. Kaan Kurtural, PhD Senior Agronomy Information Technology Manager

As the new year starts, we are getting ready to break dormancy in almond orchards to commence the 2025 growing season.  Prior to flush of root growth, immediately following bloom, leaf out beings in almond orchards.  This is important to remember to correctly apply fertilizers. 

Growers need to be cognizant of the fact nitrogen fertilizers applied prior to bloom has NO effect on bloom, early leaf growth and shoot expansion.  Remobilization of nitrogenous compounds is entirely driven by nutrients stored over winter from last year’s fertility program.  Soil nutrient uptake will not occur until trees are active and leaves are transpiring.  Without a transpiration stream pulling in soil moisture and the soluble nutrients contained in the root zone, there is no nutrient uptake.  As depicted in Figure 1 below, there must be enough leaf expansive growth for root growth to happen. 

The needs of the almond trees, especially Nitrogen cannot be met by foliar applications alone.  However, to ensure sustained leaf expansion (source of photosynthates) and mitigate untoward weather conditions such as early season heat waves such as the ones we have witnessed during the 2024 season. 

In independent studies conducted in California, foliar applications of FOLI-GRO POLISH, or FOLI-GRO TIDALWAVE or FOLI-GRO CA-ZN results indicated an average nut meat yield increase of 125 lbs/A to 364 lbs/A.  FOLI-GRO POLISH, in addition to Calcium (Ca) and Zinc (Zn) needed to drive leaf expansion early in the season utilizes 5% nitrate nitrate-nitrogen that can be delivered at 20% bloom, full bloom and petal fall (Figure 2). Likewise, adding a biostimulant to a grower standard program such as FOLI-GRO TIDALWAVE may also result in increased yields ameliorating the plant-water-atmosphere continuum.

Figure 2.  Effect of foliar fertilizer or biostimulant on nut meat yield of almond in central California. (PDF216031CA05)

Although adding the FOLI-GRO CA-ZN provided a greater nut meat yield compared to grower standard, FOLI-GRO POLISH pushed yields even higher.  These are good solutions that can ensure a more resilient orchard with higher yields.