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Spawn & Substrates
Cow Manure
Aged, screened cow manure compost for manure-loving mushrooms. Crumbly and low in odour, it blends with coir or straw and rehydrates to roughly 3 litres from a 1 kg pouch.
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Dry, sealed pouch. Just add water when you are ready to use it.
Composted, screened and dried so it arrives crumbly and ready to hydrate.
Low in nitrogen, so less ammonia and less risk of pinning delays than fresh or strawy horse manure.
Fine and crumbly, mixes with coir, straw or gypsum and stays porous once wet.
The short version
This is composted cow manure that has been screened, dried and blended with a little straw bedding. It is a nutrient base for mushrooms that grow on dung and rich soil, such as button, cremini, portobello and shaggy mane.
One 1 kg pouch rehydrates to roughly 3 litres. Mix it with coir or straw to keep it open, bring it to field capacity, pasteurise or sterilise, then spawn.
WHAT IT IS
A composted manure base, not a finished mix
Cow manure is one of the classic substrate bases for mushrooms that grow on dung and rich soil in nature. This pouch is aged, screened, dried and blended with a small amount of straw bedding. It arrives dry and crumbly with a low odour.
It carries gentle, balanced nutrition and plenty of humus to hold water. Like most manures it is low in nitrogen, and ageing and composting lower it further, so it pins more steadily than fresh or strawy horse manure. On its own, wet manure packs down into mud, so it is almost always mixed with coir or straw to keep it open and porous.
| Form | Dry, screened, crumbly compost |
|---|---|
| Pouch | 1 kg dry |
| Rehydrates to | Roughly 3 litres |
| Nutrition | Low nitrogen, high humus; varies with batch |
| Treatment | Aged, screened and dried |
HOW TO USE IT
Building a manure substrate
Manure-loving species take a nutrient-rich substrate, so a manure mix is usually pasteurised or, for the richest blends, sterilised before spawning. Two common home recipes are below. Treat the numbers as a starting point and adjust to your method.
Mix
Blend the manure with coir or chopped straw so it stays open. A common dung-lover mix is two parts manure to one part coir to one part vermiculite, with about 5% gypsum by weight. For a leaner straw-based mix, blend manure into pasteurised straw at roughly a quarter to a third of the volume.
Hydrate to field capacity
Add water and mix until evenly damp. At field capacity a firm squeeze of a handful gives only a drop or two of water, not a stream, and the mix is not dry.
Pasteurise or sterilise
For a leaner mix, pasteurise by holding it in water at about 65 to 75C for one to two hours, and do not let it pass 80C. For richer manure mixes, many growers sterilise instead, for example a pressure cooker at 15 psi for 90 minutes or more. Let it cool fully before the next step.
Spawn and colonise
Mix in colonised grain or sawdust spawn. A spawn rate around 10 to 20% by weight works for richer substrates; leaner mixes do better nearer 20 to 30%. Keep clean, then let it colonise before you move to fruiting.
Gypsum (calcium sulfate) at roughly 2 to 5% of the dry weight keeps grain from clumping and adds calcium and sulfur. It is pH neutral, so it steadies conditions rather than raising or lowering pH the way lime does.
STORAGE AND SAFETY
Keeping it and handling it
Store the sealed pouch somewhere cool and dry. Dry, it keeps well. Once you have hydrated it, treat it and use it the same day, since damp untreated manure will start to grow its own moulds and bacteria.
This is a composted animal product. Wear a dust mask when handling it dry, work in a ventilated space, and wash your hands afterwards. People with weak immune systems should take extra care, as composts can carry moulds.
WHAT IT IS NOT FOR
Not a casing layer on its own
Do not use cow manure on its own as a casing layer. A casing needs to be low in nutrition so it holds moisture without being fully colonised. Manure is nutritious and colonises through, so it fails as a pure casing. For casing, use a peat and lime mix or a coir and vermiculite layer instead. Manure is the food base underneath, not the cap on top.
Common questions
Frequently asked
Mushrooms that grow on dung and rich soil, such as button, cremini, portobello and shaggy mane. Wine cap is mainly a wood-chip species, but a little manure can be added to its bed.
No. Mix it with coir or straw so it stays porous, hydrate it to field capacity, then pasteurise or sterilise it first.
Pasteurise leaner mixes at about 65 to 75C for one to two hours, not past 80C. Sterilise the richest manure mixes, for example a pressure cooker at 15 psi for 90 minutes or more.
No. It is too rich and colonises through. Use a low-nutrition peat and lime or coir casing instead.
At about 2 to 5% by weight it stops clumping and adds calcium and sulfur. It is pH neutral and steadies conditions rather than shifting pH.
One 1 kg pouch rehydrates to roughly 3 litres before you blend in coir or straw.
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Supplied for legal gourmet mushroom cultivation. Spores and cultures are sold separately for microscopy and legal home growing only.
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