Blue Oyster Mushroom Spawn

Blue Oyster Mushroom Spawn – 5 lb Bag

Blue Oyster (Pleurotus ostreatus var. columbinus) is one of the most productive and forgiving species you can grow. Famous for its cold tolerance and aggressive colonization, this strain thrives in cooler Canadian climates where other oyster varieties struggle. If you need a grain spawn that performs in unheated barns, garages, or seasonal grow rooms, Blue Oyster is your best bet.

Why Growers Choose Blue Oyster

• Cold-tolerant fruiting – Fruits reliably at temperatures as low as 10°C, making it perfect for fall, winter, and early-spring production in Canada.
• Aggressive colonizer – One of the fastest colonizing species, which reduces contamination risk and shortens your production cycle.
• Heavy yields – Produces dense, meaty clusters across multiple flushes with excellent biological efficiency.
• Substrate flexibility – Grows well on pasteurized straw, supplemented hardwood sawdust, and masters mix.

What You Get

Each 5 lb bag contains fully colonized organic millet grain spawn from our CFIA-licensed production facility in Brantford, Ontario. We start every batch from lab-tested genetics and produce all spawn in-house under sterile conditions. The result is clean, vigorous grain spawn you can trust for commercial-scale production or serious hobby growing.

How to Use

Break up the grain spawn and incorporate it into your substrate at a 10–15% spawn rate. Blue Oyster excels on pasteurized straw packed into XL grow bags or columns. For sawdust-based production, mix spawn evenly into supplemented hardwood blocks. Colonize at 20–24°C, then drop temperatures to initiate pinning. Blue Oyster responds well to a cold shock for robust fruiting.

Growing Conditions

• Fruiting temperature: 10–18°C (50–64°F)
• Humidity: 85–95% RH during fruiting
• Light: Indirect ambient or 12-hour cycle
• Fresh air: High air exchange for compact, well-formed clusters
• Substrates: Pasteurized straw, hardwood sawdust, masters mix

Scaling up? Save with our Blue Oyster Spawn Case (6x 5 lb). Or try our Black Oyster Mushroom Spawn for warmer-season production.