Nutrient Roles in the Wild Blueberry Crop Year Production

 

Hello everyone,

We are hearing increasing concerns about differences in fruit bud size and development across wild blueberry fields this spring. In many crop fields, bud break and separation have begun across the province, giving us clearer insight into how last year’s drought is influencing this season’s crop potential.

Variation in bud size can directly affect development rate, flowering timing, and ultimately yield potential. These differences largely reflect variability in nutrient reserves stored in the plants. Adequate nutrient availability and proper developmental timing are critical for achieving a strong average yield.

Last fall, blueberry wood nutrient analysis conducted by Dr. Harrison Wright (AAFC) indicated that several nutrient levels were lower than those observed in 2024, particularly some key micronutrients. Reduced nutrient reserves following drought stress are likely contributing to the uneven bud development we are now observing.

In this short blog post, we would like to review the fundamentals of nutrient needs during the wild blueberry crop year. Over the coming weeks, we will continue discussing this topic through additional updates and grower resources.

During our next Virtual Wild Blueberry Grower Meeting on May 20, we will welcome guest speaker Jessica D’Entremont (NutriAg), who will provide a brief presentation on nutrient functions and practical approaches to managing nutrient inputs in crop fields, with particular attention to liquid fertilizer products. A second guest speaker will also present on mulching practices in wild blueberry production at the same meeting.

To register for the meeting, please visit:
Wild Blueberries Virtual Grower Meetings 2026 Registration

We hope this short communication helps growers better understand the key roles of nutrients during the crop year, supports decision-making regarding liquid fertilizer use, and contributes to improved berry quality and yield potential.

 

Nutrient Importance in Wild Blueberry Production

Wild blueberries grow naturally in acidic, low-fertility soils; however, adequate nutrient availability remains essential for maintaining plant vigor, optimizing fruit yield, and sustaining long-term field productivity. Nutrients influence every stage of crop development, including vegetative growth, flower bud formation, pollination success, fruit set, berry size, and winter survival.

Plant nutrients are grouped into macronutrients, required in relatively large quantities, and micronutrients, needed in smaller amounts but equally vital for normal plant function. Deficiencies or imbalances in either group can limit plant growth, reduce flowering potential, and negatively affect fruit quality.

Wild blueberry production operates within a two-year cycle. The sprout year focuses on vegetative growth and the establishment of future yield potential, while the crop year relies heavily on stored nutrients and carbohydrates accumulated during the previous season to support flowering and fruit development.

 

Nutrient Function During the Crop Year

Following vegetative growth achieved during the sprout year, plants enter the crop year with pre-formed flower buds and stored nutrient reserves. These reserves largely determine early-season performance, influencing bud break, flowering progression, pollination success, fruit set, and early berry growth.

Recent blueberry wood analysis indicates reductions in several key nutrients — particularly Calcium (Ca), Magnesium (Mg), Zinc (Zn), and Boron (B) — ranging from approximately 13% to 36% below the previous years’ levels. Combined with seasonal stresses, including last year’s drought effects, these reductions highlight the importance of targeted nutrient supplementation during the crop year.

Because crop-year nutrient uptake opportunities are limited, careful selection of nutrients and application timing is critical for supporting reproductive development and maximizing yield potential.

 

Secondary Macronutrient: Calcium (Ca) — Cell Strength & Fruit Firmness

Calcium plays a central role in maintaining plant structure and fruit quality during the crop year. It is essential for cell wall formation, resulting in stronger plant tissues, improved berry firmness, and enhanced post-harvest shelf life.

Adequate calcium availability supports:

• Active root growth
• Shoot tip development
• Reduced fruit breakdown and soft berries

Calcium is relatively immobile within the plant, meaning deficiencies cannot be corrected by redistribution from older tissues. A consistent external supply is therefore required during periods of rapid growth, flowering, and berry formation.

 

Micronutrients Essential for Flowering and Fruit Set

Several micronutrients become especially important during the crop phase of wild blueberry production.

Boron (B) — Flowering & Pollination Success

Boron is one of the most critical micronutrients during the crop year. It supports pollen viability and pollen tube growth, enabling successful fertilization and seed development. Adequate boron directly improves fruit set and berry size, while deficiencies often lead to poor berry formation and reduced yields.

Zinc (Zn) — Growth Regulation

Zinc contributes to plant growth regulation through its role in hormone production. It supports healthy shoot and leaf development and helps synchronize plant growth stages, ensuring uniform flowering and fruit development across fields.

Manganese (Mn) — Metabolic Activity

Manganese functions primarily as an enzyme activator involved in photosynthesis and key metabolic processes. Adequate manganese supports overall plant metabolism and helps maintain energy production required during flowering and fruit growth.

 

Management and Liquid Fertilizer Product Selection in 2026 Crop Fields

The crop year provides only limited opportunities to supplement nutrients. Integrating liquid fertilizers into scheduled fungicide applications allows producers to efficiently support crop nutrition without additional field passes.

Producers should focus on two key application windows.

1. Bud Break / Bud Separation

(Monilinia Blight Spray Timing)

Nutrients to consider

• Boron (B)
• Zinc (Zn)

Locally available products

• BoronMax — 0.3 L/acre
• ZincMax — 0.5 L/acre
• Zinc DL — 1.0 L/acre

 

2. Flowering Period

(Botrytis Bloom Blight Spray Timing)

The objective is to support successful flowering, fertilization, and early berry development.

Nutrients to consider

• Calcium (Ca)
• Boron (B)
• Magnesium (Mg)
• Zinc (Zn)

Locally available products

• SillCalMax — 1.0 L/acre
• BoronMax — 0.3 L/acre
• ZincMax — 0.5 L/acre
• TruPhos Magnesium — 1.0 L/acre
• Cal-Bor-Moly — 3.0 L/acre
• Zinc DL — 1.0 L/acre