Growers have traditionally used peat as a casing medium and now face the challenge of finding an alternative product that is both proven as a casing material and economically viable. Whilst much research has been carried out internationally to try to find alternative materials that can be used as a casing soil, the most obvious option is the use of imported peat in the form of “ready made” casing. This material consists of a blend of deep dug wet peat with lime added to neutralise the peat to allow the mycelium from the compost inoculate the casing layer and ultimately stimulate the mycelium to produce mushrooms.

The principle advantages are:

Reduced handling

Because the casing is pre-mixed with lime (normally Sugar Beet Lime, a by product of the sugar processing industry) in essence the casing is ready to use as soon as it is delivered to the farm. In reality though, due to some moisture loss during shipping, most growers will re-hydrate the product before putting on the beds of compost. Individual growers will find the optimum time to do this, some up to two weeks before use. The bags of casing should be opened up in a clean casing bay and re-hydrated with the application of water. The casing should be turned and watered a few times to allow the peat absorb the water so that it will be available to the mycelium as it starts to produce mushrooms. Harte Peat casing does not need to be sterilised as it is pathogen free due to the depth that it is dug from at source. Growers may be wary of this, but if the casing bay or mixing area is kept clean and isolated from the growing rooms and spent compost, there should be no cross contamination from disease infected crops.

High water holding capacity

Peat is harvested vertically which gives a natural blend of both wet brown and wet black peat. The wet black peat has a high water holding capacity and will give its water up slowly during the growing period. The high fibre content of the brown peat allows the casing material to retain its structure to give an open casing.


We are a professional company with strict internal control processes to ensure the highest standards of quality. We recognise the need for consistency of supply, as this allows a grower to know exactly what they are getting every week. If the product is consistent a grower will become familiar with it and will learn to use it to the best of thier ability.

Fig 2. Harte Peat casing soil in a shelf growing system.

Our casing can be bought in different bag sizes but the important factor for the grower to consider is the recovery of peat from a container. We have a technical support team experienced in the supply of casing and in different growing techniques, and will support all our customers in terms of advice and back up. The use of our peat will certainly have the  benefits of higher yields, higher quality mushrooms and reduced incidences of disease. Harte Peat, a family run answer to a worldwide industry

In summary,

when considering your casing supplier, consider the following:

  • C - Consistency
  • A - Affordability
  • S - Service
  • I - Internationally recognised
  • N - Necessary quality controls
  • G - Good technical back up
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