Mushroom Compost:


  • Mushroom compost is a dark black compost.
  • Mushroom compost consists of chicken manure, horse manure, peatmoss and straw.
  • Mushrooms are grown on this compost medium at mushroom farms. This compost then undergoes a steaming prosess to kill all mushroom spawns before being distributed to us. Thus to prevent mushrooms growing in our customers gardens.
  • This steaming prosess also contributes to a WEED FREE MUSHROOM COMPOST.
  • Weeds can be in dormant soil for many years and when fed with compost they can emerge and start growing. Wind and birds are the main distributors of weed seeds.
  • NEVER plant anything directly into mushroom compost as this is not a growing medium on its own. It must be mixed with soil.


  • Mushroom Compost can be collected at our premises in loose quantities during office hours except on Sundays. (if own labour is supplied you are welcome to load loose quantities on any given Sunday.)
  • Mushroom Compost is also available in bags for collection as well as delivery. (min.10 big bags, 20 small bags for delivery.)
  • Mushroom Compost can also be delivered to your doorstep, min. 1cub/mtr, max. 5cub/mtr. (see pricelist for further details)
  • 20cub/mtr deliveries can also be arranged if the terrain is suitable for horse and trailer rigs.

Mushroom Compost making process:

The critical factors in producing good quality mushroom compost are:

  1. Very good hygiene to prevent contamination by unwanted microbes
  2. The right proportions of manure and straw
  3. The use of wheat straw rather than any other kind
  4. The generation of sufficient heat to properly pasteurize the compost
  5. An adequate supply of Calcium
  6. An alkaline pH that reaches pH 7 (neutral) when composting is complete.

The process begins by soaking the straw in water and then leaving it to drain so that it remains only just moist. Only a few drops should come out when squeezing a handfull of the moist straw.

Manure and Gypsum are then mixed into the straw and the heap formed up. Only poultry or horse manure should be used, the heap should then heat up quickly. Other types of manure will not produce enough heat.

For every bale of wheat straw, use about 36 liters of dry poultry manure (not litter, but actual manure) or Horse manure. As an alternative to mixing, the heap can be built up in layers of these proportions.

Gypsum is used at the rate of about 6.5 kg per tonne of manure, so a light sprinkling on each layer should suffice. If the compost looks greasy or sticky when turning, simply add more Gypsum. Do not ad lime, only gypsum.

Ideally, a heap should be six feet high in order to quickly develop enough heat, but a compost bin or tumbler could be used to contain and insulate smaller quantities. The compost should then be thoroughly turned on a weekly basis until it stops re-heating and the pH falls to neutral. At this point it should be used immediately so that only mushroom spawn has the chances to populate it.

The process of growing mushrooms is then simply laying the compost into boxes, inoculating it with spawn and keeping it away from sunlight and draughts while the fungus grows. The ideal temperature range is 13-15 degrees C. Lower temperatures will only slow growth, but higher temperatures should be avoided.

Air movement that can dry the compost is harmful, but good ventilation is essential since as little as 2% Carbon Dioxide in the air can harm the developing mushrooms.

Once the fungus has filled the compost and pinheads begin to appear, moistened peat 'casing' is laid over the top and the mushrooms will begin to grow. They are harvested by twisting them out and the holes are re-filled with casing material.

Mushroom Compost samples: