High Humidity in Crops Effects on Plant Health and Nutrition The Challenge Humidity plays an important role in regulating water movement within plants. While adequate moisture is essential for crop growth, prolonged periods of high humidity can create challenges for nutrient transport, plant development and crop quality. High humidity is particularly common in protected cropping environments, dense crop canopies and periods of prolonged warm, wet weather where air movement is limited. The impact depends on crop type, growth stage and the duration of humid conditions. Sensitive crops may experience nutritional imbalances, reduced quality and increased susceptibility to disease. How High Humidity Affects the Plant Plants rely on transpiration to move water and nutrients from the roots to actively growing tissues. Under highly humid conditions, the difference between moisture levels inside the leaf and the surrounding air becomes smaller, slowing transpiration. High humidity can: Reduce the movement of water through the plant Restrict the transport of nutrients such as calcium Increase the risk of soft, weak growth Affect tissue development and crop quality Create favourable conditions for certain diseases Reduce overall crop resilience The effects are often most noticeable in young leaves, developing fruit and other rapidly growing tissues. How High Humidity Affects Nutrient Movement Some nutrients depend heavily on water movement within the plant. Calcium is particularly vulnerable because it is transported through the transpiration stream. When transpiration slows, calcium delivery to developing tissues may become restricted, even when soil calcium levels are adequate. High humidity can contribute to: Reduced calcium movement within the plant Localised calcium deficiencies Nutritional imbalances in rapidly growing tissues Reduced fruit quality and storage potential Increased risk of physiological disorders Boron movement can also be affected, particularly in crops with high demand during flowering and fruit development. What to Look For Symptoms associated with prolonged high humidity may include: Growth and Development Symptoms Soft or weak growth Poor tissue development Reduced crop uniformity Slower canopy drying Quality Symptoms Poor fruit firmness Reduced storage and shelf life Increased incidence of quality disorders Reduced marketable yield Nutritional Symptoms Tip burn Calcium deficiency symptoms Distorted young leaves Nutrient imbalance symptoms Nutritional Support During High Humidity Maintaining balanced nutrition can help support healthy growth and crop quality when environmental conditions limit nutrient movement. Calcium Calcium is essential for cell wall development, tissue strength and crop quality. Maintaining an adequate supply is particularly important during periods of restricted transpiration. Boron Boron supports cell development, flowering and reproductive growth. It also works closely with calcium in supporting healthy plant development. Potassium Potassium plays an important role in water regulation, carbohydrate movement and overall crop quality. Biostimulants Biostimulants can support natural plant processes associated with stress management, resilience and recovery under challenging environmental conditions. When Foliar Nutrition Can Help High humidity can reduce the movement of nutrients within the plant, particularly calcium. Foliar nutrition provides a direct route for supplying nutrients to actively growing tissues, helping maintain nutritional balance and supporting crop quality when environmental conditions limit normal nutrient movement. Targeted foliar applications can be particularly valuable during periods of rapid growth, flowering and fruit development, when nutrient demand is high. OMEX Foliar Solutions for High Humidity CalMax, CalMax B and CalMax Gold Best suited for: Supporting calcium nutrition during periods of restricted transpiration High humidity can limit calcium movement within the plant, increasing the risk of deficiency symptoms in developing tissues. Benefits Provides readily available calcium Supports cell wall development and tissue strength Helps maintain fruit quality and firmness Supports healthy new growth Additional Benefits of CalMax B Provides both calcium and boron Supports flowering and reproductive development Helps maintain nutrient balance during periods of rapid growth K41 / K50 Best suited for: Supporting crop quality and plant function Potassium plays a central role in water regulation and carbohydrate transport within the plant. Benefits Supports water balance within the plant Supports carbohydrate production and translocation Helps maintain crop quality Supports healthy growth and developmen BIO 20 Best suited for: General environmental stress support BIO 20 combines mineral nutrition with seaweed-derived biostimulant properties to support crops during periods of challenging environmental conditions. Benefits Supports plant resilience during periods of environmental stress Combines nutrition with biostimulant activity Encourages root development and plant vigour Supports nutrient uptake during challenging growing conditions Helps maintain overall crop performance during stress periods High Humidity at a Glance High humidity can reduce transpiration and slow nutrient movement within the plant. Calcium transport is particularly affected, increasing the risk of quality-related disorders. Soft growth, tip burn and reduced fruit quality are common symptoms. Calcium, boron and potassium play important roles in supporting crop performance under humid conditions. Foliar nutrition can help maintain nutrient supply when environmental conditions restrict nutrient movement within the plant.