The cultivation of “Golden Teachers,” a popular and hardy strain of Psilocybe cubensis, typically spans four to eight weeks from inoculation to the first harvest. The timeline depends significantly on the chosen cultivation method and consistency of growing conditions. Understanding the distinct phases of growth—colonization, pinning, and subsequent flushes—is essential for managing expectations and ensuring a successful harvest.
Phase One: Substrate Colonization
The colonization phase is the first and longest period, where the fungal network (mycelium) spreads through its food source. This phase begins with inoculation, introducing spores or liquid culture into a sterilized grain spawn. Mycelial growth is kept in a dark environment with optimal temperatures, often between 75°F and 81°F, to encourage rapid growth while inhibiting contaminants.
The mycelium generally takes 10 to 20 days to fully colonize the initial grain spawn. Once covered, the grain is mixed into a larger, less nutrient-dense bulk substrate, such as coconut coir and vermiculite. This step, known as spawning to bulk, requires an additional 14 to 21 days until the block is fully consolidated. Maintaining consistent temperatures is important, as colder conditions substantially slow down the mycelium’s metabolic activity.
Phase Two: Pinning and First Harvest
Once the bulk substrate is fully colonized, conditions must change to signal the mycelium to begin fruiting, a transition known as “pinning.” This involves introducing fresh air exchange, dropping the temperature to 70–75°F, and exposing the substrate to a light cycle. The drop in carbon dioxide and introduction of light act as environmental triggers, stimulating the formation of tiny mushroom primordia, or “pins.”
Pins typically appear within 3 to 7 days after fruiting conditions are introduced. They then enter a rapid growth phase, developing into mature, harvest-ready mushrooms. The time from the first visible pin to a mature mushroom, identifiable by the stretching cap and tearing veil, is usually 5 to 10 days. The first harvest, or “flush,” is often ready around 4 to 6 weeks from the initial inoculation date.
Subsequent Growth Cycles: Flushes
After the first harvest, the substrate can produce multiple subsequent waves of mushrooms, known as “flushes.” Since the substrate expends significant water and nutrients, it must be rehydrated. Growers typically soak the substrate block in water for several hours to replenish its moisture content.
Following rehydration and draining, the substrate is returned to the fruiting environment, where the cycle of pinning and maturation begins again. The time between harvesting one flush and the appearance of the next flush’s pins is generally 5 to 10 days. Subsequent flushes often produce fewer individual mushrooms, but the fruits can be larger. This cyclical process continues for several weeks until the substrate’s reserves are depleted.
Environmental Variables Affecting Speed
The speed of the entire growth cycle is highly dependent on the stability and optimization of the surrounding environment. Temperature is the most significant variable, as the mycelium operates best within a narrow range, typically 75–81°F during colonization and 70–75°F during fruiting. Temperatures outside of this optimal window can substantially slow down the growth rate at all stages.
Humidity is another powerful regulator of growth, particularly during the fruiting stage, where a high relative humidity (often maintained above 90%) is necessary to prevent the mushrooms from drying out. Insufficient moisture in the air or the substrate can cause the mycelium to stall or the pins to abort, halting the timeline.
Fresh air exchange (FAE) also plays a critical role. The reduction of carbon dioxide levels through regular air exchange is one of the primary signals that triggers the transition from colonization to the rapid growth of the pins. Consistent control over these variables allows a grower to keep the timeline on track for a predictable harvest.