How to Grow Oyster Mushroom (Pleurotus SP.) on Straw in Plastic Bags

Oyster mushrooms (Pleurotus spp.) are increasingly recognized as one of the most profitable and sustainable food crops in the world. Packed with protein, vitamins, and minerals, oyster mushrooms are often called the “vegetarian’s meat” and are an excellent substitute for animal-based proteins. More farmers and urban growers are turning to oyster mushroom farming using rice straw—a widely available agricultural waste product—as a low-cost substrate.

This updated guide explains how to cultivate oyster mushrooms using rice straw, with the latest best practices for success in tropical and subtropical climates like the Philippines and Southeast Asia.

Why Oyster Mushrooms and Rice Straw Are a Perfect Match

Rice straw is typically discarded or burned after harvest, contributing to environmental issues like air pollution and soil degradation. By converting it into a growing medium for mushrooms, farmers can generate income while reducing agricultural waste. Oyster mushrooms grow naturally on lignocellulosic materials like straw, making it an ideal substrate.

Materials You’ll Need

• Dried rice straw (100 kg)
• Slaked lime (Ca(OH)₂) – 2 kg
• Clean water
• Plastic grow bags (18×25 cm or 20×30 cm)
• Commercial oyster mushroom spawn (2.5–3.0 kg)
• Rice husks (optional, for spawn mixing)
• Cotton balls
• Rubber bands
• Sharp knife
• Nylon rope or wire for hanging bags

Step 1: Preparing the Rice Straw

Soaking in Limewater

1. In a large container, soak 100 kg of dry rice straw in a limewater solution made from:
   • 2 kg of slaked lime
   • Enough water to just cover the straw
2. Soak for 30–60 minutes to reduce contaminants and soften the fibers.

Lime increases pH, which helps kill harmful fungi and bacteria.

Pre-Fermentation

1. After soaking, pile the straw on a clean cement floor.
2. Cover with plastic sheet or old sacks, leaving the top of the pile exposed for air circulation.
3. Allow the straw to ferment for 7–10 days.

Turning the Straw

Turn the pile every 3 days to ensure uniform fermentation:

• From top to bottom
• Bottom to top
• Inside to outside
• Outside to inside

Moisture Check

Grab a handful of straw, squeeze tightly, and check your hand:

• Slightly wet palm = perfect moisture
• Dry palm = add more water

Step 2: Preparing the Mushroom Spawn

You can buy mushroom spawn from accredited suppliers or mushroom technology centers. Ensure they are:

• Disease-free
• Fresh (no foul odor or discoloration)
• Stored in cool conditions

You may mix the spawn with rice husk (1:1 ratio) to improve oxygen flow and germination rate.

Step 3: Filling and Sealing the Mushroom Bags

Filling Procedure

1. Open a clean plastic grow bag.
2. Add 3–5 cm of compacted straw at the bottom.
3. Sprinkle the spawn mixture around the edge (not in the center).
4. Repeat layering: straw → spawn → straw, until nearly full.
5. Leave 5–7 cm space from the top.

Sealing the Bags

1. Place a clean cotton plug at the mouth of the bag.
2. Seal with a rubber band.
3. Tie 3–5 bags together using nylon rope.
4. Hang the bags in the mushroom house with mouths facing upward.
5. Leave space between each bag for air circulation.

Step 4: Incubation and Mycelium Development

Store the bags in a shaded, well-ventilated area with a temperature of 25–30°C. Avoid direct sunlight and strong winds.

Within 25–30 days, white mycelium will colonize the bag fully. This indicates readiness for fruiting.

Step 5: Initiating Mushroom Fruiting

1. Use a sterile knife to make 4–6 slits (3–5 cm long) on each bag.
2. Spray water lightly on the bags 2–3 times daily to maintain moisture.
   • Do not overwater — no pooling inside the bag.
3. Remove the cotton plug.
4. Re-hang the bags upside down (mouth facing down) on a clean wire or rope.

Step 6: Harvesting Your Oyster Mushrooms

After 7–10 days, small buttons will emerge from the slits.

Harvest Tips

• Harvest mushrooms when caps are fully open but not curled.
• Cut gently with a clean knife.
• Do not pull, to avoid damaging the mycelium.

You can repeat this harvesting cycle 3–4 times, with 5–7 days of rest (no watering) between flushes.

Expected Yield:

From 100 kg of rice straw, you can expect:

• 50–80 kg of fresh oyster mushrooms
• Depending on variety, climate, and management

Economic Benefits and Sustainability

• Startup-friendly: Suitable for small land areas and low capital.
• Organic-ready: No synthetic fertilizers or pesticides required.
• Marketable: High demand in wet markets, supermarkets, and health-conscious consumers.

Many agripreneurs are integrating oyster mushroom production into diversified farm enterprises or online direct selling.

Expert Tips

• Use solar dryers or air-drying racks to produce dried mushrooms for added shelf life.
• Explore value-added products like mushroom chicharon, chips, or powder.
• Join farmers’ cooperatives or government programs (e.g., DOST, DA) for training and equipment grants.

References & Acknowledgments

• Department of Agriculture – High Value Crops Development Program (DA-HVCDP)
• DOST-PCAARRD: Mushroom Industry Roadmap 2025
• Vietnam Ministry of Agriculture & Rural Development
• FAO Asia-Pacific Guidelines on Mushroom Production (2024 Edition)