Best Way to Grow Your Own Mushrooms
Home production of mushrooms does not require a large amount of space. A useful crop can be obtained from just a few medium-depth boxes and as mushrooms require a cool, dark place to grow, they can be placed out of sight in any shaded corner.
Gardening catalogues and some retail outlets offer complete mushroom-growing kits, but this is not the most economical way of going about things. There is an element of uncertainty about growing mushrooms, and the ready-spawned growing kits are often considered the most reliable method of producing a good crop. However, it is not a difficult process to prepare the containers and sow spawn; so if you accept the slight risk of disappointment it is worthwhile trying this vegetable, and there is the greater satisfaction when you succeed.
Mushroom spawn can be purchased separately and the growing mixture can be the same as that used for your other indoor crops. Horse manure is often recommended, and it is commonly thought that mushroom growing involves heaps of foul-smellingin which the mush-rooms can thrive, but this is not the modern method. If you have access to horse manure it can be mixed with your usual potting medium. Provided the manure is well rotted it should be odourless, and you do not need large amounts. However, it is not essential.
A good growing medium is the spent mushroom compost from a previous cropping. This is occasionally offered for sale by the bag, or you may be able to acquire some from a mushroom-growing acquaintance. After raising your first crop, you will have your own spent compost. But as some of the nutrients have been used by the previous mushroom crop, do not use this as the sole growing medium; combine it with a commercial peat-based mixture.
Mushrooms are best grown in flat boxes or trays, as they do not need much depth, though plastic seed trays are a little too shallow. Wooden boxes of the type used by greengrocers and market traders for storing and transporting fruit and vegetables make ideal containers for mushrooms. These are often discarded when empty, or you may be able to buy them quite cheaply from the trader. Plastic tubs also make good containers: you can use those sold for plant growing or recycle large-size containers of the type used to package ready-mixed adhesives and plasters. These should be thoroughly scrubbed with boiling water to remove all traces of their previous contents, which may have contained toxic chemicals. Add a little detergent to the washing water and give the tubs a final good rinse with clean water.
Sowing and growing
Fill the containers to the top with the growing medium, moisten it lightly and firm it well. Sprinkle the mushroom spawn evenly over the surface and pat it in gently. Cover with the thinnest possible layer of the growing medium but do not firm this down as the pressure damages the spawn. It should be evenly moist, and in subsequent waterings it is best to use a very fine mist spray which will not disturb the delicate mycelium – the thread-like initial growths of the mushroom which are the equivalent of a root system.
A shaded location is essential. You can place the boxes in a cool, dark place such as under the kitchen sink or in a spare room or basement area. You can even put them under the bed, so in effect this is a space-saving crop, as the boxes do not take up valuable space on a sunny windowsill needed for your tomatoes and other more demanding plants. If you have no suitable hiding place, exclude the light by covering the containers with a few layers of newspaper or a sheet of black plastic. This should be loosely laid to allow ventilation; the mushrooms will develop mould if deprived of air, though a relatively damp atmosphere is not detrimental.
Apart from keeping the mushrooms shaded and moist, it is important to control the range of temperature. Extremes of heat and cold will cause the crop to fail. An average between 50°F (10°C) and 60°F (15°C) is most suitable, and the temperature should not rise above the upper limit. The spawn may be killed by temperatures much higher than this, so this aspect of cultivation needs particular attention during the warmer months of the year. Likewise winter crops need protection; the environment should be cool, but not cold.
Assuming all the conditions are favourable, the mushrooms should start to push up above the surface within about four weeks of sowing. Check on their progress after about three weeks and remove any covering as soon as you see the tiny white ‘buttons’ appear on the surface of the growing medium. Once this has occurred, uncover the containers but do not expose them to bright light. Fungi are plants of the shade, unlike green plants which need the sunlight in order to produce chlorophyll.
If you remove some mushrooms at the ‘button’ stage, those which remain have more space in which to grow and can become larger. (The tiny buttons, sliced very thinly, are delicious raw in salads.) To take out a mushroom, twist it carefully – do not pull it sharply upwards or you will dislodge the mycelium of other mushrooms not yet grown. If any pieces are left behind from the mushrooms you have removed, be sure to take them out also; if left in the growing medium they will quickly rot and may spoil the remainder of the crop.
About one pound (450g) of mushrooms is produced in a square foot (900cm2) of growing area. If you have plenty of space and would like to grow mushrooms in quantity to obtain a continuous supply (they can be sown at any time of year), obtain a number of containers and stack them in a staggered arrangement as they are filled. As you harvest one crop, simply rearrange the containers and reuse those which have been emptied to house the next sowing.