Oyster mushrooms, scientifically known as Pleurotus species, are known for their rapid growth cycle. The entire process, from adding mushroom spawn to the substrate until the first mature cluster is ready to pick, typically spans three to six weeks. This timeline is split into two distinct phases: the internal growth of the fungal network and the rapid development of the visible mushroom body.
The Colonization Phase: Mycelium Development
The cultivation journey begins with the colonization phase, which is the longest period in the cycle. This phase starts when mushroom spawn is introduced to a prepared substrate like straw or sawdust, allowing the mycelium (the vegetative body of the fungus) to spread internally. The goal, often called the “spawn run,” is for the mycelium to fully permeate the material, forming a dense, white network. This phase generally takes between 10 to 21 days. During this internal growth period, the fungal block does not require light, as energy is focused on establishing the network.
The Fruiting Phase: Pinning to Harvest
Once the substrate is fully colonized, the transition to the fruiting phase begins with “pinning.” Pinning is the appearance of tiny mushroom primordia, often resembling small knots or bumps on the surface of the block. The subsequent growth of the fruiting body is remarkably fast, usually taking only four to seven days from the initial pin appearance to harvest. The precise moment to harvest is determined by the cap shape; they should be picked when the edges begin to uncurl and flatten out. Prompt harvesting is necessary, as delaying can result in the release of spores, reducing the mushroom’s shelf life and flavor.
Key Environmental Factors Affecting Growth Speed
The speed of the oyster mushroom life cycle depends on environmental controls, which can accelerate or slow the timeline. Temperature is a significant variable: mycelial colonization prefers warmer temperatures (optimal between 28°C and 30°C), while fruiting requires a slight drop (18°C to 24°C).
Humidity also impacts the fruiting timeline, as low moisture can cause developing pins to dry out. A high relative humidity, ideally between 85% and 95%, is necessary during the fruiting stage to support the rapid expansion of the mushroom bodies.
Managing carbon dioxide (CO2) concentration is important for a fast transition to fruiting. High CO2 levels are tolerated during colonization but must be lowered significantly (below 600 parts per million) to trigger pinning and proper stem formation. Consistent fresh air exchange (FAE) is used to lower CO2, ensuring primordia develop into large, healthy mushrooms.
Understanding Subsequent Flushes
After the first harvest, the substrate block will often produce multiple flushes of growth. The mycelium requires a period of rest and recovery before it can initiate the next set of mushrooms, which typically takes seven to fourteen days between flushes. To encourage the next flush, growers often re-soak the substrate block in water to replenish lost moisture. While multiple flushes are common, each subsequent flush is typically smaller and may take slightly longer to develop as nutrients are depleted.