Storage, Handling & Preservation
Mildew
Mildew is a type of fungal growth that develops in damp, humid environments and can affect cannabis plants during cultivation or storage. If left untreated, mildew can damage plant tissue, reduce yields, and compromise the quality and safety of harvested cannabis.
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What Mildew Is
Mildew is a common fungal organism that grows on living plants and organic materials when environmental conditions favor its development. In cannabis cultivation, mildew typically appears as a white, gray, or slightly fuzzy coating on leaves, stems, or flowers. It thrives in environments with elevated humidity, poor air circulation, and prolonged moisture, making environmental management a critical part of prevention.
Common Causes of Mildew in Cannabis Cultivation
Several factors contribute to mildew outbreaks in cannabis grow spaces. High relative humidity, overcrowded plants, inadequate ventilation, and excess moisture on foliage create favorable conditions for fungal growth. Temperature fluctuations and stagnant air can further increase the likelihood of mildew developing, particularly in dense plant canopies where moisture remains trapped for extended periods.
Effects on Plant Health and Crop Quality
Mildew interferes with normal plant function by covering leaf surfaces and reducing the plant’s ability to efficiently exchange gases and absorb light. As the infection spreads, affected leaves may discolor, curl, or die prematurely, weakening overall plant vigor. If mildew reaches developing flowers, it can significantly reduce the appearance, aroma, potency, and marketability of the harvested cannabis.
Prevention Through Environmental Management
Preventing mildew is generally more effective than attempting to eliminate an established infection. Growers reduce risk by maintaining proper humidity levels, providing consistent airflow, spacing plants appropriately, and removing excess foliage when necessary. Regular inspection of leaves and flowers allows early detection, making it easier to isolate affected plants before the fungus spreads throughout the cultivation area.
Treatment and Control Strategies
When mildew is discovered, prompt action is necessary to limit its spread. Infected plant material is often removed and discarded, while environmental conditions are adjusted to discourage further fungal growth. Growers may also sanitize tools and workspaces after handling infected plants to prevent cross-contamination. Severe infestations can require the disposal of heavily affected plants to protect the remainder of the crop.
Importance in Post-Harvest Storage
Although mildew is most commonly associated with growing plants, improper drying and storage conditions can also encourage fungal growth after harvest. Cannabis stored with excessive moisture or in environments with high humidity remains vulnerable to mildew and other fungi. Proper drying, curing, airtight storage, and humidity control help protect harvested flower and preserve its quality over time.
Related terms:
Powdery Mildew, Mold, Relative Humidity, Air Circulation, Defoliation, Plant Disease, Contamination, Environmental Control
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