Go to

Grey Oyster Mushroom Substrate
High-Yield Substrate Blocks

Grey Oyster (Pleurotus ostreatus) Substrate Solutions

The Grey Oyster is a cornerstone of the exotic mushroom industry.
At CNC Substrates, we recognize that different farm models require different biological and economic strategies.
We have engineered two distinct substrate solutions to optimize production for every scale of operation: our high-volume Straw-Based system and our precision Wood-Based system.

CNC Substrates produces high-yield pasteurised Grey Oyster straw-based blocks designed for large professional farms, as well as sterilised Grey Oyster wood-based blocks more adequate for smaller volume. Both substrates prioritize high-density clustering, thick succulent caps, and rapid crop rotation.

Substrate Formulation

Grey Oysters are incredibly vigorous.
Our formulations is engineered to provide an “easy-access” nutrient profile that allows the mycelium to outpace competitors and reach the first flush faster than standard straw-based methods.

High-Volume Straw-Based Substrate

The Industrial Standard for Cost-Efficiency

Designed for large-scale commercial growers, our straw-based substrate is the ideal choice for farms where volume is high and cost-per-kilogram is the critical metric.

  • Format
    17.5 kg blocks.
  • Best For
    Industrial-scale farms with automated handling and high-capacity climate-controlled rooms.

Key Advantages

  1. Cost-Effective
    Utilizing high-quality cereal straw from our circular supply chain, these blocks offer the best economic return for high-tonnage production.
  2. Bulk Pasteurized
    Processed to maintain a beneficial microbial balance that protects the crop during large-scale incubation.
  3. Optimized for Logistics
    Standardized sizing for mechanical racking and industrial transport.

Precision Wood-Based Substrate

The “Ready-to-Fruit” Solution for Specialty Growers

For smaller farms, urban producers, and specialty growers, ease of use and hygiene are paramount.
Our wood-based blocks provide a premium, low-labor alternative.

  • Bulk Sterilized
    Produced in Europe’s only bulk-sterilization facility, ensuring a completely clean environment for elite mycelial growth.
  • Ease of Use
    Lightweight and easy to handle manually, requiring no specialized machinery or large-scale infrastructure.
  • Ready-to-Fruit
    Delivered in an advanced state of colonization, allowing for rapid turnaround—often moving from delivery to harvest in 7–14 days.
  • Premium Quality
    Wood-based media typically produce denser, meatier clusters with a superior shelf life for the specialty retail market.

Key Advantages

  • Bulk Sterilized
    Produced in Europe’s only bulk-sterilization facility, ensuring a completely clean environment for elite mycelial growth.
  • Ease of Use
    Lightweight and easy to handle manually, requiring no specialized machinery or large-scale infrastructure.
  • Ready-to-Fruit
    Delivered in an advanced state of colonization, allowing for rapid turnaround—often moving from delivery to harvest in 7–14 days.
  • Premium Quality
    Wood-based media typically produce denser, meatier clusters with a superior shelf life for the specialty retail market.

The Supplements

 
Nitrogen Supplements (Nutrients)

To enhance biological efficiency, the base (straw or Hardwood Sawdust) is enriched with a nutrient boost from agricultural origin.

This targeted nitrogen enrichment fuels the rapid growth cycle of Pleurotus ostreatus, supporting the formation of dense, fleshy caps and improving the total harvest weight.

The supplementation level is carefully calibrated to maximize yields while managing the metabolic heat generated during the intensive incubation phase.

The Sterilization Standard

 
Substrate Preparation & Thermal Treatment

The material is hydrated to a precise 65%–70% moisture content using filtered water, ensuring the mycelium has the necessary hydration to support the high water demands of the developing fruiting bodies.

Our Grey Oyster substrate undergoes a rigorous thermal processing cycle tailored to its specific composition.

We utilize bulk pasteurization for straw-based materials to maintain a selective microbial balance, and high-temperature sterilization for wood-based substrates to ensure the complete elimination of competitive fungi and deep-seated pests.

This controlled thermal and moisture profile ensures a reliable, pathogen-free start for every production cycle, regardless of the substrate medium.

Product Formats

  • Inoculated (Rapid Run)
    Freshly inoculated blocks.
    Due to the aggressive nature of Grey Oyster, these blocks colonize exceptionally fast (typically 12–16 days).
  • Ready-to-Fruit (Fully Mycelium-Bound)
    Completely white, colonized blocks ready for the fruiting room.

    Advantage: This format allows for the highest possible “turns” per year in a fruiting chamber. Simply slit the bag and expose to fresh air for pins to emerge within 4–7 days.

Strain Library

We use common commercial standard strains in Europe.

  • Custom Inoculation
    Available for large-scale commercial contracts (>10.000 blocks).
    Let us know, email or call us now.
  • Commercial Standard
    Focused on a massive, thick stem with a dark, marbled cap.
    Excellent storage life and resistance to bruising.

Yield Expectations

Grey Oyster is famous for its massive first flush.
While it can produce three or more flushes, commercial growers typically focus on the first two to maintain high-quality clusters.

Straw-Based Substrate

  • Biological Efficiency (BE)
    80% – 140%
  • Yield Data
    For a straw-based 17.5 kg pasteurised block, growers can expect a total yield of 3.50 kg – 6.10 kg of fresh mushrooms over two flushes.

Wood-Based Substrate

  • Biological Efficiency (BE)
    55% – 75%
  • Yield Data
    For a wood-based 2.5 kg sterilised block (approx. 0.88kg – 0.9kg dry matter), growers can expect a total yield of 0.5 kg – 0.625 kg of fresh mushrooms over two flushes.

Efficiency Tip
70% of the total yield is typically achieved in the first 10 days of the fruiting cycle.

Disclaimer
Yield expectations for CNC substrate blocks are indicative only. Actual results may vary depending on the strain, growing conditions, facility design, hygiene, handling, and cultivation management. CNC Substrates cannot guarantee a specific yield, biological efficiency, or number of flushes, as these factors are outside our direct control after delivery.

Ready to Optimize Your Grey Oyster Yields?

High-quality harvests begin with a sterile, energy-dense foundation.

Contact our specialists today to discuss your production requirements and see how our premium hardwood blocks can support your farm’s consistency.

E-mail us Call us