The Ultimate Guide to Growing King Oyster Mushroom (Pleurotus eryngii)
King Oyster mushroom (Pleurotus eryngii) is prized for its thick, meaty stem and savory umami flavor. Unlike other oyster mushrooms, King Oyster has a long shelf life, a firm texture that holds up well in cooking, and exceptional market value. It is widely cultivated across Asia and increasingly popular in North America among gourmet chefs, plant-based eaters, and mushroom enthusiasts.
This in-depth guide will walk you through every step of growing King Oyster mushroom, from choosing substrates and inoculation to ideal fruiting conditions, harvesting, and storage. We’ll also include helpful links to trusted resources—including The Spore Depot—to get you started with high-quality spawn and supplies.
What Is the King Oyster Mushroom (Pleurotus eryngii)?
Pleurotus eryngii, commonly known as King Oyster mushroom, is the largest species in the oyster mushroom family. Unlike other oyster mushrooms that grow in clusters, King Oysters typically form individually with thick, cylindrical stems and small, caramel-colored caps.
In the wild, King Oysters are saprophytic, feeding on decaying plant matter—particularly the roots of herbaceous plants. Cultivated varieties thrive on sterilized media like hardwood sawdust, straw, and grain mixtures.
Why Grow King Oyster Mushrooms?
✔ Highly Profitable – Sells for $10–$20 per pound
✔ Versatile in Cuisine – Popular in vegan, Asian, and gourmet dishes
✔ Meaty Texture – Often used as a plant-based meat substitute
✔ Long Shelf Life – Stores well compared to other oyster mushrooms
✔ Relatively Easy to Grow Indoors – Adaptable to small-scale and commercial setups
Getting Started: Growing King Oyster Mushroom
Growing King Oyster mushroom is slightly more demanding than other oyster species, mainly because it requires more specific environmental conditions to develop the signature thick stems and small caps. However, with controlled humidity, CO₂, and temperature, growers can produce high-yield, market-ready mushrooms.
Where to Get King Oyster Spawn
To start your grow, you’ll need high-quality Pleurotus eryngii spawn or liquid culture. Reliable vendors include:
- ✅ The Spore Depot – Grain spawn, sawdust spawn, and liquid cultures
- Fungi Perfecti – Gourmet mushroom products and literature
Best Substrates for Growing King Oyster Mushroom
King Oyster mushrooms thrive on nutrient-rich substrates with good water retention. Unlike common oysters, King Oysters do not grow well on straw alone—they require denser, supplemented substrates.
Recommended Substrate Mix:
- 80% hardwood sawdust (oak, maple, or beech)
- 20% wheat or rice bran (for added nutrients)
- Optional: 2% gypsum (improves structure and pH balance)
- Moisture content: 60–65% (substrate should feel like a wrung-out sponge)
🛠 You can purchase pre-made blocks or mix your own and sterilize in grow bags or containers.
🛒 For prepared substrates and supplies, check out The Spore Depot’s Grow Kits.
Step-by-Step Process for Growing King Oyster Mushroom
Step 1: Substrate Preparation
- Mix hardwood sawdust, bran, and water in the proper ratio.
- Pack into filter patch bags or autoclavable containers.
- Sterilize at 15 PSI for 90–120 minutes in a pressure cooker or autoclave.
- Allow substrate to cool to room temperature before inoculating.
Step 2: Inoculation
Once your substrate is cooled, introduce King Oyster mushroom spawn under sterile conditions:
- Work in a still air box or under a laminar flow hood
- Break up the grain spawn and mix thoroughly into the substrate
- Seal the bags or containers with breathable filters
📍 Spawn Rate: Use 5–10% spawn by substrate weight (e.g., 100g spawn for 1kg substrate)
🧪 Liquid culture can also be used to inoculate sterilized grain, which is then expanded and used to inoculate sawdust blocks.
Step 3: Incubation Period
Place inoculated bags or containers in a dark, warm space for colonization.
📍 Incubation Conditions:
- Temperature: 70–75°F (21–24°C)
- Relative humidity: 70%
- Duration: 14–21 days
- No light necessary
You’ll know it’s ready when the mycelium fully colonizes the substrate and starts forming dense, white or greyish mycelial clumps near air holes or surfaces.
Fruiting King Oyster Mushrooms: Environmental Controls Are Key
To achieve thick stems and small caps—the commercial King Oyster “look”—you must manipulate CO₂, humidity, and light levels carefully.
Fruiting Conditions:
- Temperature: 60–65°F (16–18°C)
- Humidity: 85–95%
- Light: 500–1000 lux (indirect or grow lights, 12 hours/day)
- CO₂ Levels: 2000–5000 ppm (high CO₂ promotes stem growth)
To achieve desired morphology:
- For thicker stems, maintain high CO₂ during early pin formation (seal the grow bag until pins form).
- Once pins develop, cut the bag or open air holes to reduce CO₂ and allow caps to expand slightly.
Harvesting King Oyster Mushrooms
🌱 Harvest when:
- Stems are thick and firm (2–6 inches tall)
- Caps are still small and not fully opened
- Surface is smooth and not cracking
🔪 Use a clean knife to cut mushrooms at the base. Handle gently to avoid bruising.
💡 Tip: King Oysters are often harvested in bunches, but they can also be harvested individually depending on your desired appearance.
Post-Harvest: Storage and Use
🥶 Storage:
- Refrigerate in paper bags or containers for up to 14 days
- Avoid sealing in plastic to reduce moisture buildup
🔥 Cooking & Use:
- Excellent when grilled, pan-seared, roasted, or braised
- Popular as a vegan scallop substitute (slice stems into medallions)
- Holds shape and texture in soups and stews
Yield Expectations for King Oyster Cultivation
A fully colonized 5-lb block can yield:
- 1.0–1.5 lbs of fresh mushrooms over 2–3 flushes
- First flush produces the highest quality mushrooms
To maximize yields:
- Hydrate between flushes by soaking or misting
- Allow rest periods of 7–10 days between flushes
Common Challenges and Solutions When Growing King Oyster Mushroom
❌ Long, thin stems (legginess)
Cause: Low CO₂ levels too early
Fix: Delay ventilation during pinning stage
❌ Dry or cracked caps
Cause: Low humidity
Fix: Mist more frequently or use a humidifier
❌ Contamination (green or black mold)
Cause: Poor sterilization or excess moisture
Fix: Improve sterilization process, discard infected bags
Where to Buy King Oyster Mushroom Spawn and Supplies
✅ Top Sources:
- The Spore Depot – Pleurotus eryngii spawn, liquid cultures, and kits
- Fungi Perfecti – Educational materials and cultures
Helpful Growing Resources
📘 Recommended Reading & Guides:
- The Spore Depot Blog – King Oyster Tips
- Cornell Small Farms Project – Mushroom Production
- Growing Gourmet and Medicinal Mushrooms by Paul Stamets
- Fungi Ally – King Oyster Growing Techniques
Conclusion: Start Growing King Oyster Mushrooms Today
Growing King Oyster mushroom (Pleurotus eryngii) is a rewarding experience for hobbyists and commercial cultivators alike. With its rich flavor, market demand, and aesthetic appeal, it’s no wonder this species continues to grow in popularity.
By following the steps in this guide—choosing the right substrate, monitoring environmental conditions, and sourcing quality spawn from trusted vendors like The Spore Depot—you’ll be well on your way to producing beautiful, gourmet King Oyster mushrooms with impressive yields.
Whether you’re growing for your kitchen, farmers market, or small mushroom business, Pleurotus eryngii is a mushroom worth mastering.
#KingOysterMushroom #GrowingKingOysterMushroom #PleurotusEryngii #TheSporeDepot #MushroomCultivation #FungiFarming #GourmetMushrooms #OysterMushroomGuide
