Restarting a mushroom grow kit to produce a "second crop," often referred to as a second flush, is a common practice that primarily involves rehydrating the spent substrate block. This process replenishes the moisture essential for the mycelium to generate new mushrooms.
Preparing for Your Second Flush
Before attempting to restart your kit, ensuring a complete harvest from the first flush is crucial. This sets the stage for optimal conditions for subsequent growth.
Complete Harvest is Key
- Carefully harvest all mature mushrooms from your first flush. This includes picking any small "pins" (tiny mushroom primordia) that did not fully develop. Leaving old or undeveloped mushrooms can encourage rot or contamination, which can hinder future flushes.
- Twist and pull the mushrooms gently at the base to remove them without damaging the substrate.
The Rehydration Process: Your Kit's Second Wind
The most critical step in restarting a mushroom grow kit is rehydration. Mushrooms are over 90% water, and the substrate rapidly dries out during the first flush as the mushrooms grow. Soaking the block replenishes this lost moisture, signaling the mycelium to prepare for a new growth cycle.
Soaking the Substrate Block
- Submerge in Cold Water: Place your harvested mushroom block into a bowl or container of clean, cold tap water. Cold water can sometimes help "shock" the mycelium into producing new growth.
- Ensure Full Submersion: The block will likely float. Use a clean, heavy object (like a smaller plate or a sealed bag of water) to weigh it down, ensuring it is fully submerged.
- Soaking Duration: The soaking time can vary depending on the kit type and mushroom species, but a general guideline is 6 to 24 hours. For most standard kits, 8-12 hours is often sufficient. The goal is to allow the substrate to fully reabsorb water without becoming waterlogged.
- Observation: You might notice tiny air bubbles rising from the block during soaking, indicating it's absorbing water.
Draining Excess Water
- Remove from Water: After the recommended soaking time, remove the block from the water.
- Gentle Drain: Allow any excess water to drain off the block for 15-30 minutes. You can gently press the block to help release some water, but avoid squeezing too hard, which could damage the mycelial structure.
Returning to Ideal Growing Conditions
Once rehydrated and drained, the block is ready to be placed back into its fruiting environment.
Placement and Environment
- Return to Grow Bag/Tent: Place the rehydrated block back into its original grow bag, humidity tent, or designated fruiting chamber.
- Maintain Humidity and Temperature: Continue to provide the same optimal humidity and temperature conditions that led to a successful first flush. This typically involves regular misting inside the bag or chamber and ensuring proper air exchange.
- Patience: Now, the waiting game begins. The mycelium needs time to recover and initiate new pin formation.
What to Expect: Your Second Crop
After rehydration and returning to ideal conditions, the mycelium will begin to colonize the rehydrated substrate and produce new pins. Just like the first time, with proper rehydration and care, you'll find that before you know it, you'll have your second crop of mushrooms emerging, ready for harvest.
Differences Between Flushes
| Feature | First Flush | Second Flush (and Subsequent) |
|---|---|---|
| Yield | Often the largest, most vigorous | Typically smaller, but still significant and tasty |
| Appearance Time | Usually faster after initial setup | May take slightly longer after rehydration |
| Mushroom Size | Can produce larger individual mushrooms | Often smaller, but potentially more numerous |
| Preparation Needs | Initial setup, misting | Rehydration (soaking) after harvest, misting |
It's common for subsequent flushes (third, fourth, etc.) to yield fewer mushrooms as the nutrients in the substrate become depleted. However, with good care, many kits can provide several flushes of delicious homegrown mushrooms.
