Grow Your Own Mushrooms

Posted on: 24 July 2008 by Gareth Hargreaves

Mushrooms are easy to grow at home and they provide a delicious, nutritious source of protein.

Mushrooms, which are fungi and not vegetables at all, are an obvious choice for the self-sufficient gardener who has space to spare indoors.

Mushrooms have a higher mineral content than meat, twice as high as any other vegetable, and contain more protein than any other vegetable except for certain types of bean.

Another good thing about growing mushrooms is that the compost you need for growing them can all end up in your garden outside.


In warm weather you can grow mushrooms outdoors or indoors without artificial heating, using the method I shall describe. In the winter keep the temperature over 60°F / 16°C.

Never leave mushrooms in direct sunlight.

Soil Treatment

To grow mushrooms you need boxes which ideally should be two and a half feet / 75 cm long, nine inches / 25 cm wide and nine inches / 25 cm deep.

You can buy suitable compost and this is really the best thing to do for growing small quantities of mushrooms.

However, to make enough compost for 60 square feet / 6 sq m is not difficult.

Get four bales of wheat straw - no other straw will do - and shake it out into layers, soaking it thoroughly with water. Leave it for a day or two, but throw on more water from time to time, because it must be saturated.

You should also have: seven pounds / 3 kg of gypsum - from a builder, 28 lbs / 12.7 kg of poultry manure, and 14 lbs / 6.3 kg of mushroom compost activator.

Stacking Mushrooms In Boxes

Allow at least six inches / 15 cm between the top of one box and the bottom of another. There should also be perhaps a dozen half inch / 1.5 cm holes in the bottom of each box. I like cedarwood boxes best, but you can use fibreglass trays.

Stacking Mushrooms In BoxesWhen the straw is thoroughly wet, spread some out 12 inches / 30 cm deep over an area five feet / 1.5 m square.

Shake over this layer a trowelful each of the poultry manure, gypsum and activator. Add another foot / 30 cm of straw and on this another sprinkling of the other goodies, until all the materials have been used up. The heap should be about six feet / 1.8 m high. If it is out of doors cover it with an old carpet, paper, or plastic.

By the fourth day the temperature of the heap should be 160°F / 71°C. Leave it another two days, then turn it so the outsides are in the middle. If any part of the heap appears dry at this turning sprinkle water on it, just enough to moisten it but not enough to wash away the special ingredients. When you turn the heap, shake out the straw thoroughly and rebuild very carefully. The success of your crop depends on this care.

After another six days turn again. Be even more sparing with water, but if there are any dry patches or grey patches, sprinkle them lightly. Then, after four more days, turn yet again. If the compost appears too damp apply more gypsum.

Six days later the compost will be ready for the boxes.


When it is ready for use, the compost should be fairly dry and springy; it should consist of short pieces of rotted straw but should not be sticky. Fill each box, tamping the compost down well with a brick, until the final topping up is level with the top of the box.

By now you will have bought some spawn. There is "manure" spawn which comes in lumps which you break into small pieces, and "grain" spawn which you simply scatter on the compost. I suggest that beginners use manure spawn, because it is easy to use and reliable.

Mushroom SpawnMushroom Spawn

Plant each piece of manure spawn about an inch / 2.5 cm deep, with five inches / 13 cm between the pieces.

Cover with a layer of wet newspaper.

Care While Growing

During the next week or two, do not let the temperature fall below 60°F / 16°C; 70°F / 21°C is even better. On the other hand beware of overheating; 90°F / 32°C may kill the spawn.

After three weeks you should see the white threads of the mycelium growing in the compost. At this point you must apply "casing". Mix some well-moistened horticultural peat with the same bulk of freshly sterilized loam - the loam should be from permanent grassland. Put an inch and a half / 4 cm layer of mixed peat and loam on top of the compost and press it down gently. Mushrooms should appear about three weeks later. Give them a little water. Keep the temperature between 60°F / 16°C and 64°F / 18°C.


When you harvest mushrooms twist them out. When the crop seems over, try and persuade it to go on cropping a little longer by watering it with a dilute salt solution. Eventually dump the spent compost on your compost heap, wash the boxes with formaldehyde solution, and put the boxes out to weather for several weeks before you use them again.

John Seymour

The New Self-Sufficient GardenerThis extract is taken from The New Self-Sufficient Gardener: The Complete Illustrated Guide to Planning, Growing, Storing and Preserving Your Own Garden Produce, by John Seymour, published by DK, available from all good bookshops, RRP £20, or online at Amazon for £13.20.

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