Design your monotub with optimal substrate depth, hole placement, and airflow. This calculator ensures proper gas exchange and humidity retention for maximum yields.
A monotub (monotubic fruiting chamber) is a self-contained growing environment that maintains proper humidity, temperature, and fresh air exchange for mushroom cultivation. It's the most popular fruiting chamber for home growers due to its simplicity and effectiveness.
Standard: 3-4 inches. Provides adequate nutrition and moisture retention while allowing proper colonization. Deeper isn't always better.
Fresh Air Exchange holes provide oxygen and remove CO₂. Spacing varies by species: 4-8 inches apart depending on requirements.
Holes positioned 2 inches above substrate create optimal air circulation without drying the surface excessively.
Low FAE Species:
Medium FAE Species:
High FAE Species:
Problem: Fuzzy feet (mycelium growing up stems)
Solution: Increase FAE - add more holes, increase hole size, or reduce polyfill
Problem: Dry substrate surface
Solution: Decrease FAE - add polyfill, reduce hole size, or mist more frequently
Problem: Small mushrooms with long stems
Solution: Too much CO₂ - increase FAE significantly
Both work. Polyfill allows adjustable FAE (pack tighter for less air, looser for more). Micropore tape is simpler but offers less control. Many growers start with tape and switch to polyfill if needed.
Not recommended. Drilling sends plastic debris into substrate and risks contamination. Always drill holes before adding substrate. If you must modify, do so extremely carefully.
Optional. Some designs use lid holes for additional FAE, others rely solely on side holes. Side holes only is simpler and works well for most species. Add lid holes if you need more air exchange.
Ideally, never during fruiting if your monotub is properly designed. Opening introduces contaminants and disrupts climate. Only open for harvesting or emergency adjustments.
Yes, but ensure each tub gets adequate light and has space for air circulation around all sides. Don't stack directly on top - use shelving with gaps between levels.
54-66 quart tubs are perfect for beginners. Large enough for good yields (2-5 lbs per flush) but small enough to manage easily. Avoid tubs smaller than 32 qt or larger than 100 qt initially.
A single substrate batch typically produces 2-4 flushes over 4-8 weeks. The plastic tub itself lasts indefinitely with proper cleaning. Clean thoroughly with 10% bleach solution between grows.