Matching Plant Nutrition with Almond Tree Physiology

Producing a high-yielding almond crop begins long before harvest. Throughout the growing season, almond trees progress through a series of closely coordinated developmental stages, from floral bud development and bloom to nut establishment, kernel filling and maturation. Each stage places different physiological and nutritional demands on the tree, making the timing of nutrition just as important as the nutrients supplied.

These developmental changes are regulated by plant hormones, including auxins, cytokinins, gibberellins and abscisic acid, which coordinate processes such as flowering, fruit retention, cell division, carbohydrate allocation and kernel development. At the same time, amino acids play a fundamental role in protein synthesis, enzyme production and the metabolic activity required to sustain growth during periods of high energy demand.

The GrowGreen almond program combines Fish Emulsion, which supplies biologically derived amino acids and organic nutrients from microbially digested fish, with Microbe Plus Kelp, a source of phytohormones and bioactive compounds derived from microbially digested kelp. Applied together with Xtend®, the program complements the tree’s natural physiological processes by providing biological and mineral nutrition during the key stages of reproductive development.

The following program has been developed around the major physiological stages of almond production, aligning foliar nutrition with the periods when the tree’s nutritional demand and metabolic activity are greatest.

Two GrowGreen program options are available to suit different orchard management preferences. Growers can choose the convenience of AminoKelp Citrus Doctor, which combines biological and mineral nutrition in a single product, or the flexibility of applying Fish Emulsion and Microbe Plus Kelp together. Both programs have been developed to complement almond tree physiology throughout the growing season.

Recommended GrowGreen Growing Program for Almond trees

1. Pre-Bloom

What’s happening inside the tree?

As temperatures increase and dormancy ends, almond trees become physiologically active. Flower buds complete their development before opening, root growth resumes and stored carbohydrate reserves are mobilised to support the rapid transition into flowering. This stage establishes the foundation for successful bloom, pollination and subsequent nut production.

Natural hormonal activity

The transition from dormancy to flowering is regulated by naturally occurring plant hormones. Gibberellins and cytokinins contribute to bud development and renewed shoot growth, while auxins help coordinate the growth of developing tissues. Together, these hormones regulate the physiological changes required for the tree to enter its reproductive phase.

Why are amino acids important?

As metabolic activity increases, the demand for amino acids also rises. Amino acids are essential for the synthesis of proteins and enzymes involved in cell division, respiration and energy metabolism. They also contribute to the production of new tissues as the tree prepares for flowering and early reproductive growth.

Which key nutrients are important during this stage?

Nitrogen supports the production of new shoots and leaves while contributing to the proteins and enzymes required for active growth.

Phosphorus plays an important role in energy transfer and root activity, supporting the mobilisation of reserves needed for flowering.

Boron is involved in flower development and helps prepare reproductive tissues for successful pollination and fertilisation.

Why apply the GrowGreen program?

Applying the GrowGreen program during pre-bloom complements the tree’s transition from dormancy to active growth. Whether using AminoKelp Citrus Doctor + Xtend® or Fish Emulsion + Microbe Plus Kelp + Xtend®, the program provides biologically derived amino acids, phytohormones, bioactive compounds and mineral nutrition to complement the physiological processes associated with flowering and early reproductive development.

2. Bloom & Nut Set

What’s happening inside the tree?

During bloom, flowers open and pollination is followed by fertilisation, initiating nut development. The tree simultaneously begins shedding flowers and young fruit that cannot be supported, while directing carbohydrates and nutrients towards successfully developing nuts. This is one of the most critical stages in determining final yield, as the number of nuts retained establishes the crop’s production potential.

Natural hormonal activity

Following fertilisation, auxins and gibberellins produced by developing embryos contribute to fruit retention and early nut growth. Cytokinins promote active cell division within the young nut, while the balance between these hormones influences whether developing fruit is retained or naturally shed.

Why are amino acids important?

Rapid cell division and the formation of new tissues increase the demand for amino acids. They are required for protein synthesis, enzyme activity and the metabolic processes that support the establishment of developing nuts during this highly active stage of growth.

Which key nutrients are important during this stage?

Boron supports pollen tube growth and successful fertilisation while contributing to early reproductive development.

Calcium is required for the formation and stability of new cells as the young nut begins to develop.

Zinc contributes to enzyme activity and the synthesis of growth compounds involved in early reproductive growth.

Why apply the GrowGreen program?

Applying the GrowGreen program during bloom and nut set complements the high metabolic activity associated with fertilisation, early cell division and nut establishment. By supplying biological and mineral nutrition during this critical stage, the program complements the physiological processes that influence early crop development.

3. Early Nut Development

What’s happening inside the tree?

Following successful nut set, the developing nuts enter a period of rapid growth. Cell division continues while the shell expands and hardens, and the kernel begins to form. At the same time, the tree increases the movement of water, carbohydrates and nutrients to support the growth of developing nuts while maintaining a healthy canopy capable of sustaining photosynthesis.

Natural hormonal activity

Cytokinins continue to regulate active cell division within the developing nut, while auxins and gibberellins contribute to tissue expansion and normal fruit growth. These naturally occurring hormones coordinate the development of the shell and the early formation of the kernel.

Why are amino acids important?

As the developing nut increases in size, amino acids are required for the continued synthesis of proteins, structural compounds and metabolic enzymes. They contribute to the biochemical processes associated with tissue development and the increasing metabolic activity of the growing nut.

Which key nutrients are important during this stage?

Calcium contributes to the development of new cell walls as the shell and nut tissues continue to expand.

Potassium supports carbohydrate transport and helps regulate water movement within the tree during periods of active growth.

Magnesium is essential for chlorophyll production and photosynthesis, supporting the production of carbohydrates required by the developing crop.

Why apply the GrowGreen program?

Applying the GrowGreen program during early nut development complements the tree’s increased demand for biological and mineral nutrition as the shell develops and the kernel begins to form. Providing nutrition during this period supports the physiological processes associated with sustained nut growth and canopy function.

4. Kernel Fill

What’s happening inside the tree?

As the kernel enters its final stage of development, the tree directs increasing amounts of carbohydrates, nutrients and water towards the developing kernels. Dry matter, oils and other storage compounds accumulate, determining final kernel weight and quality. Maintaining an active canopy during this period is essential to sustain photosynthesis and provide the energy required for kernel filling.

Natural hormonal activity

Hormonal activity gradually shifts from promoting rapid cell division to coordinating the accumulation of storage reserves and the progression towards maturity. Abscisic acid plays an increasingly important role as the kernel develops and approaches the final stages of ripening.

Why are amino acids important?

Amino acids continue to contribute to protein synthesis and the metabolic processes involved in kernel development. They also support the production of enzymes required for the accumulation of storage compounds during the final stages of nut growth.

Which key nutrients are important during this stage?

Potassium supports the transport of carbohydrates from the leaves to the developing kernels, contributing to kernel filling.

Magnesium maintains chlorophyll production and photosynthetic activity, helping sustain the supply of carbohydrates during this high-demand period.

Nitrogen contributes to the synthesis of proteins required for continued kernel development and final kernel composition.

Why apply the GrowGreen program?

Applying the GrowGreen program during kernel fill complements the tree’s increased demand for biological and mineral nutrition as carbohydrates and nutrients are directed towards the developing kernels. Providing nutrition during this stage complements the physiological processes associated with kernel filling, maturation and the production of high-quality almonds.

5. Conclusion

Successful almond production relies on providing appropriate nutrition throughout the growing season as the tree’s physiological and nutritional requirements change. By aligning biological and mineral nutrition with key stages of development, growers can implement a consistent and practical approach to complement normal tree function and support productive orchards.

GrowGreen offers two program options to suit different management preferences. Whether using the convenience of AminoKelp Citrus Doctor or the flexibility of Fish Emulsion and Microbe Plus Kelp, both programs have been developed around the same physiological principles to provide nutrition throughout the almond production cycle.