Welcome to the cozy world of indoor mushroom growing! Whether you’re working with oyster mushrooms or lion’s mane, this guide walks you through each step—from supplies to harvest.
🧺 Supplies You’ll Need
- Mushroom spores or liquid culture (oyster, shiitake, lion’s mane, etc.)
- Substrate materials:
- Coco coir
- Straw (chopped and pasteurized)
- Vermiculite
- Hardwood sawdust
- Optional: coffee grounds
- Pressure cooker (15 PSI)
- Jars or grow bags with filter patches
- Syringes (for spores or liquid culture)
- Clear plastic tote or monotub
- Drill & polyfill
- Thermometer & hygrometer
- Alcohol spray, gloves, and mask
- Misting bottle
🪴 Making Your Own Substrate
🥥 Coco Coir & Vermiculite Mix (Best for oyster mushrooms)
- 650g coco coir brick
- 2 quarts vermiculite
- 1 gallon boiling water
Mix and let hydrate overnight in a tote. Fluff well before use.
🌾 Straw Substrate
- Chop straw into small pieces
- Pasteurize in water at 160–170°F for 1 hour
- Drain and cool completely before use
🌳 Hardwood Sawdust Mix (Great for lion’s mane, shiitake)
- 5 parts hardwood sawdust
- 1 part wheat bran
- Adjust to 60–65% moisture (squeeze test: only a few drops should come out)
🍯 How to Make Liquid Culture
Ingredients:
- 500 ml distilled water
- 10 g light malt extract (or honey)
Sterilize in a jar for 20 mins at 15 PSI. Let cool. Inoculate with spores and incubate at 70–75°F for 10–14 days.
đź’‰ How to Inoculate the Substrate
- Work in a clean, alcohol-sprayed space
- Inject 1–2 mL of spore or liquid culture into jars or bags
- Seal with micropore tape or use filter patch bags
- Incubate at 70–80°F in the dark for 2–3 weeks
🔥 How to Use a Pressure Cooker
- Place jars/bags on a raised rack above 1 inch of water
- Seal and cook at 15 PSI:
- Grains – 90–120 mins
- Sawdust – 90 mins
- Liquid culture – 20 mins
- Let the pressure cooker cool overnight to prevent uneven moisture in jars or bags
🧼 Sterilization Methods & When to Use Them
| Method | Use For | Notes |
|---|---|---|
| Boiling | Straw, coco coir | Simple pasteurization (160–170°F for 1 hour) |
| Cold Lime Soak | Straw | Soak in hydrated lime water for 12–18 hours |
| Pressure Cooking | Grains, sawdust | Most reliable for contamination prevention |
| Hydrogen Peroxide | Cardboard | Great for oyster mushrooms on paper |
🌡️ Growing Environment Basics
| Element | Ideal Range | Why It Matters |
|---|---|---|
| Humidity | 80–95% | Helps with pinning and prevents drying |
| Temperature | 65–75°F | Each variety has a sweet spot |
| Light | Indirect, 12 hrs/day | Triggers fruiting (especially oysters) |
| Fresh Air Exchange | 3–5x daily or passive | Prevents CO₂ buildup |
| Cleanliness | Always sterile | Reduces risk of contamination |
🌟 Tips to Increase Success
- Let your pressure cooker cool down overnight—this helps prevent moisture imbalance
- Label every jar or bag with date and strain
- Shake only when needed—early to mid colonization is best
- Flame-sterilize all tools before use
- Start with oyster mushrooms—they’re very forgiving
- Discard anything showing green mold (trichoderma)
- Keep a consistent grow room temp and humidity level
🍄 Harvest & Storage
- Harvest before caps flatten or drop spores
- Use a clean knife or twist gently
- Store fresh mushrooms in a paper bag in the fridge (5–7 days)
- Dry extras in a dehydrator (95–105°F)
- Store dried mushrooms in airtight jars with desiccant packs