Growing Strawberries crop nutrition advice

What soil type, pH, and climate do strawberries prefer?

• Strawberries thrive in well-drained, loamy soils rich in organic matter, favoring sandy loam types.
• They perform best in temperate climates with mild winters and moderate summers, benefiting from a chilling period to induce flowering.
• Coastal regions with maritime climates, like parts of California and the Pacific Northwest, are ideal.
• Strawberries prefer slightly acidic to neutral soil pH levels of 5.5 to 6.5, with adjustments using lime or elemental sulfur as needed for optimal nutrient availability.
• In soils with a high pH (above 7.5), a deficiency of phosphorus, but also of other micronutrients, may appear.
• In soils with a low pH (below 5.5), a deficiency of phosphorus, Mo, and Ca may appear.
• Irrigation is essential for high-yielding strawberry production. The plant’s root system is shallow, with 80–90% in the top 6 inches of clay and 50% in the top 6 inches of well-drained sandy loam soils. Therefore, frequent and short irrigation pulses are necessary to maximize production.

Growing Strawberries in the US

Commercial strawberry growers across the US encounter several unique soil and climate challenges that affect nutrient management:

Soil Variability: Soil types vary widely across different strawberry-growing regions, ranging from sandy soils in coastal areas to heavier soils in inland regions.  Many parts of Florida, for example, have sandy soils with poor water and nutrient retention capabilities. Likewise, many strawberry-growing regions, like across the PNW, Florida, and coastal California, have naturally acidic soils, which can affect nutrient availability, particularly for micronutrients like boron and zinc. Adjusting soil pH can be necessary to optimize nutrient uptake and prevent deficiencies. Addressing soil fertility and moisture management is essential for sustaining healthy strawberry plants and maximizing yield.

Water Management: Balancing water availability with the risk of over-irrigation and nutrient leaching is critical for optimal crop growth. Florida’s sandy soils are prone to rapid water drainage, necessitating efficient irrigation practices to maintain adequate soil moisture levels. While in California, growers face ongoing water scarcity issues exacerbated by drought conditions and competing agricultural demands, or years with extended periods of excessive rain. Regions with heavy rainfall or excessive irrigation are prone to nutrient leaching, leading to deficiencies and environmental pollution. Implementing efficient irrigation practices and using controlled-release fertilizers, like Agriform Strawberry Mix, can help mitigate nutrient loss through leaching. Including soil surfactants, like H2Flo can also improve water usage.

Seasonal Demands: Strawberry plants have varying nutrient requirements at different growth stages, with peak demand occurring during flowering and fruiting. Adjusting fertilization practices to meet seasonal demands while avoiding excesses is crucial for maximizing yield and fruit quality. Using controlled-release fertilizers, or naturally gradual-release fertilizers, like Polysulphate, can help provide crops with the nutrients they need, when they need them. Likewise, addressing deficiencies or nutrient needs with foliar or fertigation strategies can help efficiently meet plant demand.

Regulatory Compliance: California, for example, has stringent regulations regarding pesticide use, water quality, and food safety, imposing compliance burdens on growers. Likewise, organic strawberry growers face additional challenges in nutrient management. Utilizing organic amendments (like OMRI-approved Polysulphate), cover cropping, and crop rotation strategies to maintain soil fertility and balance nutrient availability is essential for organic certification compliance.

Nutrient Requirements of Strawberries

Balancing nutrients according to the specific needs of the strawberry plants and the soil conditions is essential for maximizing yield, fruit quality, and overall profitability, but several nutrients are particularly important for optimal plant growth, fruit development, and overall yield.

Macronutrients

Nitrogen: Promotes high yields and ensures vegetative growth of the crop. Plays a key role in the synthesis of proteins, which are directly involved in growth and yield.

Phosphorus: Promotes the development of a good root system. A prerequisite for flowering and the number of and maintenance of fruits. Essential for appropriate energy management in the plant. Enhances cell division.

Potassium: Enhances transport of sugars to the fruits. A cofactor of tens of enzymes. Regulates water management, mainly through stomata aperture. Enhances the sugar content of the fruit. Reduces susceptibility to many kinds of abiotic-, and biotic- stresses. Improves deep fruit color, firm flesh, shape, and overall yields.

Calcium: Promotes cell-wall stability, hence providing the plant a strong structure, and resistance to diseases. Adequate calcium prevents blossom-end rot (BER). It also provides improved shelf life.

Magnesium: Is the central part of the chlorophyll molecule, playing a key role in photosynthesis. Increases Fe utilization. Carrier of phosphorus in the plant. It is both an enzyme activator and a constituent of many enzymes. Helps obtain a deep green fruit color.

Sulphur: A structural component of proteins and peptides. Active in the conversion of inorganic N into protein. A structural component of various enzymes. A catalyst in chlorophyll production.

Micronutrients

Iron: Essential for proteins and chlorophyll synthesis. Important factor in many enzymes, associated with energy transfer and respiratory systems.

Manganese: Important roles in photosynthesis: Hill reaction (H2O splitting), electron transport, CO2 assimilation. Formation of riboflavin, ascorbic acid, and carotene.

Boron: Translocation of sugars and carbohydrates. Pollination and seed production. Cell division and cell-wall formation, related to calcium (Ca) uptake and usage.

Nutrient Deficiencies in Strawberries

Phosphorus deficiencies                       

Magnesium  deficiencies                              

Iron        

Chloride Sensitivity and Strawberries

Strawberry plants are sensitive to chloride due to its interference with nutrient uptake, disruption of osmotic balance, and potential toxicity.  In general, strawberry is considered to be one of the most sensitive crops to salinity, and specifically to chloride.

What can high chloride levels do to strawberries?

High chloride levels can outcompete essential nutrients, cause water stress, and lead to leaf burn and reduced fruit yield.  Cl-affected leaves show dry and brown leaf margins, brittle leaves, stunted plant growth, and dead roots, and plants.   The maximum permissible chloride level in the soil solution in most cases is 5–7 meq/L, which varies by variety. The maximum permissible chloride in irrigation water is 3–5 meq/L.   Chloride higher than 0.5% in the dry matter of the plant indicates chloride toxicity. 

What can growers do to manage chloride sensitivity?

Given strawberries’ sensitivity, careful irrigation management and avoiding chloride-containing water sources are crucial to mitigate its negative effects and ensure optimal plant health and productivity. Ensuring adequate soil drainage to prevent the accumulation of chloride salts in the root zone can help. Additionally, soil testing and water analysis can help identify potential chloride issues and guide appropriate management strategies to minimize its impact on strawberry crops.

Fertilization methods

In the US, the most common method of strawberry fertilization is through a combination of soil-applied fertilizers, fertigation, and foliar fertilization as a supplemental nutrient management strategy, especially during critical growth stages or to address specific nutrient deficiencies.

Soil-Applied Fertilizers

Important soil-applied fertilizers include complete fertilizers for balanced nutrition, nitrogen sources for growth, phosphorus sources for root development, potassium sources for fruit quality, and secondary nutrients like calcium and magnesium. Polysulphate is a good example of a multi-nutrient, granular, gradual-release product. Micronutrients are also crucial for various plant functions. Utilizing these fertilizers based on soil tests ensures optimal plant health and fruit production.

Controlled-release fertilizers (CRFs) for strawberry fields 

The use of CRFs for strawberry crops has continued to expand as a result of the need to save on workload, increase field productivity and reduce environmental impacts from nutrient loss. Across the US, the usage of N-P-K CRFs has caught quickly and is now practiced over 55% of the 26,000 country-wide hectares, concentrated mainly in California. 

Normally, one pre-plant application of well-designed CRF granules, like Agroblen or Agriform Strawberry Mix, can supply the majority share of the crop’s mineral requirements, achieving high yields of high-quality produce for fresh consumption. Application of additional water-soluble fertilizers (WSFs) by fertigation is also common. Additionally, combining granular Polysulphate with CRFs shows positive yield, quality, and plant health benefits.

These fertilizers are typically applied before planting or during early growth stages, based on soil tests, to ensure optimal plant health and fruit production.

Fertigation

As drip irrigation is so common with this crop, fertilization is generally done by fertigation, using fully-soluble fertilizers, adapting the N-P-K-Ca-Mg ratios according to the crop’s needs at every growth stage. Once the strawberry plants are established, fertigation becomes a primary method of nutrient application. Fertigation involves applying water-soluble fertilizers through the irrigation system, delivering nutrients directly to the root zone. This method allows for precise nutrient management and efficient plant uptake, contributing to optimal growth and fruit production.

In soil the needs of the Strawberry must be covered by  : 

1. Elements naturally present in irrigation water
2. Elements already present in the soil
3. Additional fertilizer inputs to the soil
4. Additional fertilizer intake by drip

Strawberry needs = Soil input (stock or mineralization, for example) + Water elements + Fertilizers put on the soil + Supplements during cultivation (soluble fertilizers)

Foliar feeding  

Some growers may also utilize foliar fertilization as a supplemental nutrient management approach. Foliar feeding boosts plant development, strengthening the plants against abiotic factors (e.g., drought, heat, cold soils) and biotic factors (e.g., nematodes, pests, and diseases) and correcting mineral deficiencies. Tank-mixing fertilizers with crop-protection products is a common foliar practice in fertilizing strawberries. Foliar application involves spraying liquid fertilizers directly onto the leaves, providing a quick nutrient boost during critical growth stages or addressing specific nutrient needs.

The Bottom Line

Effective fertilization practices are essential for maximizing yield and quality in commercial strawberry farming. By combining soil-applied fertilizers, fertigation, and supplemental strategies like foliar fertilization, growers can ensure that their strawberry crops receive the nutrients they need for healthy growth and abundant harvests. Ultimately, the choice of fertilization method and specific fertilizers used vary depending on factors such as soil conditions, climate, crop stage, and grower preferences.