Midwest's Select Bulk Substrate Casing Mix - 30 Pounds (BULK 6-PACK)
Midwest's Select Bulk Substrate Casing Mix - 30 Pounds (BULK 6-PACK) is backordered and will ship as soon as it is back in stock.
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Description
Description
The Select Bulk Substrate 6-Pack is six 5 lb bags — 30 lbs total — of our pasteurized, pre-hydrated coco coir mushroom substrate at bundle pricing. Same CVG blend as our single bags, stocked up for multiple monotubs or larger bulk setups.
Each bag arrives at field capacity with a balanced pH, so you go straight from fully colonized grain spawn to mixing and growing. Keeping separate 5 lb bags means you only open what you need for each tub.
- 30 lbs6 × 5 lb bags
- CVGCoir, vermiculite, gypsum
- PasteurizedReady to use
- 3–6 tubsDepending on size
- 6 monthsRefrigerated, sealed
Why buy the 6-pack
- Lower price per bag – Bundle pricing beats buying six single bags.
- Separate 5 lb bags – Open one bag at a time; the rest stay sealed for the next tub.
- Ready to use – Pre-hydrated to field capacity and pasteurized. No soaking, mixing or measuring — open the bag and add colonized grain spawn.
- Pasteurized, not sterilized – Pasteurization knocks back competing microbes while keeping the substrate's natural biology, which is what you want in a bulk grow.
- Balanced pH and minerals – Hydrated lime and gypsum buffer the pH, and Azomite trace minerals round out the blend for vigorous mycelial growth.
- Consistent batch to batch – Same texture, moisture and pH in every bag, so your results are repeatable from one tub to the next.
What's in the box
- 6 × Midwest's Select Bulk Substrate, 5 lbs each (30 lbs total)
- Pasteurized and pre-hydrated to field capacity
- Step-by-step Bulk Growing Guide
How to use it
- Start with fully colonized spawn. Grain spawn bags or jars should be completely white before you spawn to bulk.
- Break up the spawn. Massage the bag or shake the jar until the grain separates into loose kernels.
- Open the substrate. Crumble any clumps so the substrate is loose and even.
- Mix it in the tub. Combine spawn and substrate evenly in a clean monotub or tray, then level and lightly press the surface.
- Colonize, then fruit. Cover and leave it undisturbed until the surface is colonized, then introduce fruiting conditions.
Breaking up colonized spawn and mixing it into bulk substrate.
Bulk Growing Guide included. Our step-by-step bulk monotub guide walks you from colonized grain spawn to a fruiting tub.
How far does 30 lbs go?
| Monotub | Substrate | Grain spawn | Tubs per 6-pack |
|---|---|---|---|
| Small 28Q | About 4 lbs | 1 spawn bag or one 32 oz jar | 6 |
| Medium 44Q | 7.5 lbs (1½ bags) | 1 spawn bag | 4 |
| Large 66Q | 10 lbs (2 bags) | 2 spawn bags | 3 |
Specifications
| Specification | Detail |
|---|---|
| Weight | 30 lbs (6 × 5 lb bags) |
| Base | Coco coir, vermiculite and gypsum (CVG) |
| Additives | Hydrated lime, mineral water, Azomite trace minerals |
| Treatment | Pasteurized |
| Moisture | Pre-hydrated to field capacity — no water needed |
| Spawn ratio | 2:1 to 3:1 substrate to grain |
| Works with | Rye, millet, 5-grain and other colonized grain spawn |
| Storage | Sealed, cool and dry; refrigerate up to 6 months; do not freeze |
Storage: Keep bags sealed in a cool, dry place for short-term storage, or refrigerate sealed bags for up to 6 months. Do not freeze, and avoid heat, direct sun and big temperature swings that cause condensation inside the bag.
Bundle pricing: The 6-pack is already priced below six single bags, so coupon codes don't apply to it. To use a code on other items, place the 6-pack in a separate order.
Need grain spawn?Our Premium 5-Grain and Original Rye spawn bags come in 2-packs. Need less substrate? Grab a single 5 lb bag, or a 7.5 lb bag sized for a Medium 44Q tub.
FAQ
What is in Select Bulk Substrate?
A CVG base — coco coir, vermiculite and gypsum — with hydrated lime to buffer pH, mineral water and Azomite trace minerals. It comes pre-hydrated and pasteurized.
Do I need to add water?
No. Every bag is hydrated to field capacity before it ships. Open it, break up any clumps and mix in your colonized grain spawn.
Is it pasteurized or sterilized?
Pasteurized. That reduces competing microbes while keeping the substrate's natural biology, which is the standard approach for bulk substrate. Your grain spawn is what gets sterilized.
How much do I need for my monotub?
About 4 lbs for a Small 28Q, 7.5 lbs (1½ bags) for a Medium 44Q and 10 lbs (2 bags) for a Large 66Q. A 6-pack covers three 66Q tubs, four 44Q tubs or six 28Q tubs (one bag each).
What grain spawn can I use?
Any fully colonized grain spawn — rye, millet, 5-grain bags or grain jars. Aim for 2:1 to 3:1 substrate to grain.
Can I use it as a casing layer?
Yes. Mix it through as your bulk substrate, or spread a thin layer over colonized substrate as a casing.
How should I store it?
Keep bags sealed in a cool, dry place short-term, or refrigerate sealed bags for up to 6 months. Do not freeze.
Can I use a coupon code on the 6-pack?
No. The 6-pack is already priced below six single bags, so coupon codes don't apply to it. To use a code on other items, place the 6-pack in a separate order.
