Description

Bulk Golden Oyster Mushroom Grain Spawn Bag – 25–1000 Unit Packs

Scale up your Golden Oyster mushroom grows with vigorous, fully colonised grain spawn - ready to mix straight into hardwood or Master’s Mix substrates for fast, dependable colonisation. Built for growers who care about strong colonisation, clean results, and a supply they can actually rely on.

Each Golden Oyster grain spawn bag is prepared in cleanroom conditions and sterilised in a computer-controlled autoclave, taking the guesswork out of prep so you can focus on growing, not fixing problems.

Choose from 25, 50, 100, 250, 500 or 1000 unit packs for commercial consistency and better unit economics.

Need trade support, custom scheduling, or a tailored quote? Contact us and we’ll build a supply plan around your volume.

Wholesale‑Ready Golden Oyster Grain Spawn

This is our best-selling sterilised millet + milo (milo = sorghum) grain blend, optimally hydrated and fully colonised with vigorous Golden Oyster mycelium - ready to spawn straight to bulk. Sealed in a sterile bag for clean handling and consistent performance, this is a fast, reliable foundation for repeatable bulk runs at scale.

Ideal for

• Commercial farms and scaling growers who rely on consistent cycle times and repeatable results
• High-volume hobby growers who want access to wholesale pricing without complicated sourcing
• Retailers and resellers looking for a reliable, high-performing sterile grain range

Not a Bulk Buyer?

This page is for trade, wholesale, and high‑volume growers ordering 25–1000+ units.

If you’re a hobby grower or want to trial smaller quantities first, use our standard (non‑bulk) listing here.

Key Advantages

• Direct from the source - You get the best price. It's all about direct supply from a top UK mushroom supplier.
• Scale whenever you’re ready - Need 25 now or 1,000+ regularly? We’ve got you covered year-round.
• Fast bulk colonisation - A fully colonised grain bag delivers dense, distributed mycelium throughout the grain, supporting quick bulk colonisation and reducing the time the substrate sits uncolonised.
• Clean, commercial-grade sterility - Each batch is sterilised for 2.5 hours at 121°C in a computer-controlled autoclave at our Kent facility, giving you a contamination-free start.
• Perfectly balanced moisture - Grain is hydrated just right to encourage healthy, vigorous growth without inviting bacteria.
• High-quality filtration - 0.2-micron filter patches let the bags breathe while helping keep contaminants out - so you get more consistent results.

What You Get

• Bulk packs 25–1000 to match your production runs
• 1.5kg Golden Oyster grain spawn bag - fully colonised and standardised for consistent runs and simple SOPs.
• Optimally hydrated millet & milo blend for rapid colonisation
• Cleanroom-prepped and ready for spawning to bulk on arrival
• Sterilised in a computer-controlled autoclave (2.5 hrs @ 121°C)
• Lifetime Guarantee (we stand behind every bag)
• Free UK delivery on £50+ orders helps protect margins
• Pay in 3 interest-free instalments available at checkout

Built For

Product Sellers (retailers, resellers, garden centres)

• Building a production‑ready Golden Oyster spawn line with repeatable results
• Offering case quantities for serious growers
• Improving customer outcomes with a proven grain blend and guarantee

Growers (commercial & high-volume)

• Routine bulk spawning with fully colonised, clean Golden Oyster grain spawn
• Grain-to-bulk workflows (monotubs and blocks)
• Faster SOPs: no soaking/cooking/sterilising on your end

Perfect For

• Spawning directly into supplemented hardwood sawdust mixes
• Fast “take‑off” and consistent runs when expanding into bulk production substrates
• Cycle consistency when you need predictable colonisation windows (typically 3–4 weeks, culture-dependent)

What’s Included

• 1.5kg Golden Oyster grain spawn bag (per unit)
• Lifetime Guarantee coverage

Not included: spore or liquid culture syringe.

How It Works

1. Sanitise your workspace and wipe down your tools and mixing area.
2. Break up the spawn inside the sealed bag. Massage the bag to separate the fully colonised Golden Oyster grain into loose kernels.
3. Prepare your bulk substrate (wood-based). Golden Oyster performs best on hardwood-based mixes (e.g., supplemented hardwood sawdust/pellets). Make sure your substrate is properly pasteurised or sterilised for your recipe.
4. Open the bag in a clean area and mix the spawn evenly through your substrate.
5. Incubate until fully colonised.

Quality Guarantee

At Martian Mushrooms, we don't just sell supplies; we use them.

Every batch is produced with lab-first discipline: grain is soaked/cooked, hydrated to ~50% water content, and sterilised in a computer-controlled steam autoclave for 2.5 hours at 121°C.

If something goes wrong, you’re protected by our Lifetime Guarantee - built for growers who can’t afford downtime.

Technical Specifications

Martian Mushrooms vs. Competitors

Don't let grain prep slow you down. Ensure your supply chain with the UK's most reliable bulk Golden Oyster mushroom grain spawn.

Need a custom quote, white labelling, or pallet pricing (100+ units)?

Join our Growth Partner Program.