Midwest's Black Cow Manure Substrate & Casing Mix - 5 lbs
Midwest's Black Cow Manure Substrate & Casing Mix - 5 lbs is backordered and will ship as soon as it is back in stock.
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Description
Description
Midwest's Black Cow is a ready-to-use manure-based mushroom substrate: ultra-composted dairy cow manure blended with coco coir, vermiculite and pH-buffering minerals, pasteurized and fully hydrated in a 5 lb bag.
It's built for growers who prefer a traditional manure-based bulk mix without the mess of composting, pasteurizing and hydrating it themselves. Mix it with fully colonized grain spawn and go.
- 5 lbsPer bag
- ManureDairy cow, composted
- 160°FPasteurized 3–4 hrs
- HydratedReady to use
- 45 daysBest within, sealed

Why growers pick Black Cow
- Traditional manure base – Ultra-composted dairy cow manure for growers who prefer a manure-based mix.
- Pasteurized for you – Pasteurized at 160°F for 3–4 hours — no composting, cooking or pasteurizing on your end.
- Fully hydrated – Arrives at the right moisture, ready to mix with colonized grain spawn.
- Balanced pH and minerals – Gypsum, hydrated lime and a calcium, magnesium and sodium bicarbonate buffer.
- Consistent bag to bag – Same texture and moisture in every bag for repeatable results.
What's in the mix
- Ultra-composted dairy cow manure
- Coco coir
- Vermiculite
- Spring water
- Gypsum and hydrated lime
- Mineral buffer blend with calcium, magnesium and sodium bicarbonate
How to use it
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Start with fully colonized spawn. Grain spawn bags or jars should be completely white before you spawn to bulk.
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Break up the spawn. Massage the bag or shake the jar until the grain separates into loose kernels.
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Open the substrate. Crumble any clumps so the substrate is loose and even.
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Mix it in the tub. Combine spawn and substrate evenly in a clean monotub or tray, then level and lightly press the surface.
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Colonize, then fruit. Cover and leave it undisturbed until the surface is colonized, then introduce fruiting conditions.

Spawning to bulk: break up the grain and mix it through the substrate.
How much spawn per bag?
- 1 to 1.5 grain spawn bags per 5 lb bag
- About 3 quick-colonizing 24 oz jars per bag
- About 6 half-pint jars per bag
Real results

Specifications
| Specification | Detail |
|---|---|
| Weight | 5 lbs per bag |
| Base | Ultra-composted dairy cow manure, coco coir, vermiculite |
| Minerals | Gypsum, hydrated lime, calcium, magnesium, sodium bicarbonate |
| Water | Spring water — arrives fully hydrated |
| Treatment | Pasteurized at 160°F for 3–4 hours |
| Spawn per 5 lb bag | 1–1.5 spawn bags, ~3 × 24 oz jars or ~6 half-pint jars |
| Storage | Sealed, cool and dry; best within 45 days at room temp; do not freeze |
Storage: Keep bags sealed in a cool, dry place and use within 45 days at room temperature for best results. Do not freeze.
Compare our bulk substrates
| Substrate | Base | Treatment | Best within |
|---|---|---|---|
| Select Bulk Substrate | Coco coir, vermiculite, gypsum (CVG) | Pasteurized | 6 months refrigerated |
| Black Cow (this one) | Composted dairy cow manure + coir and vermiculite | Pasteurized, 160°F for 3–4 hrs | 45 days, room temp |
| Willy's Blend | Aged imported manure + 6 proprietary additives | Pasteurized, 160°F for 3–4 hrs | 45 days, room temp |
Need grain spawn?Pair it with our Premium 5-Grain Spawn Bags or 24 oz quick-colonizing jars. Running several tubs? The Black Cow 6-pack costs less per bag.
FAQ
What is in Black Cow?
Ultra-composted dairy cow manure, coco coir, vermiculite and spring water, with gypsum, hydrated lime and a mineral buffer blend of calcium, magnesium and sodium bicarbonate.
Is it pasteurized?
Yes. Black Cow is pasteurized at 160°F for 3–4 hours, which knocks back competing microbes while keeping the substrate's natural biology.
Do I need to add water?
No. Every bag arrives fully hydrated. Open it, break up any clumps and mix in your colonized grain spawn.
How much spawn do I need?
Plan on 1 to 1.5 grain spawn bags, about 3 quick-colonizing 24 oz jars, or about 6 half-pint jars per 5 lb bag.
How long does it keep?
Keep bags sealed in a cool, dry place and use within 45 days at room temperature. Do not freeze.
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.
Black Cow or Select Bulk Substrate?
Black Cow is manure-based for growers who prefer a traditional manure mix. Select Bulk Substrate is a coir-based CVG blend with a longer refrigerated shelf life.



