All About Mould And Fungi

All About Mould And Fungi

What is Mould and Fungi?

The term fungi includes moulds and yeasts, and many types of fungi are responsible for helping the decomposition of waste within a compost pile.

Most fungi live on dead or dying material (plant or animal) and obtain energy by breaking down organic matter. They are mainly associated with digesting the carbon and harder to digest materials such as cellulose. There are also specialist fungi groups that can decompose the highly resistant lignin, a woody substance found in most paper and wood based items. Wood decay is also often associated with white and brown rot specialist fungi.

What Should I do if I Find Mould or Fungi in the HOTBIN?

Whilst they can be unsightly microorganisms such as bacteria and fungi are part of a normal composting process and responsible for the decomposition of waste.

Fungi’s can digest dry, acidic and carbon rich materials that bacteria struggle to digest. Once these tougher materials have been broken down, it allows the bacteria to continue the decomposition process.

If you find mould or fungi in your HOTBIN and wish to remove them we recommend wiping the mould off the surfaces of the HOTBIN using kitchen roll (we strongly advise wearing gloves whilst doing this) and then composting the used kitchen roll in the HOTBIN to destroy any spores.

How to Minimise Mould or Fungi

Signs of mould or fungi in the HOTBIN can be an indication that the HOTBIN is operating at lower temperatures as most are usually found in moderate temperatures of 21-24°C (although some can live as high as 49°C). Therefore, maintaining hot composting temperature can help to minimise the chance of mould or fungi becoming visible in your HOTBIN. We would recommend you continue to feed your HOTBIN every couple of days with fresh waste, paper, and woodchip to keep the internal temperatures high as possible.

Types of Mould and Fungi

White Mycelium

A common fungus consisting of a mass of branching which can look like a white blanket. It is often visible on the surface of rotting material, especially in moist conditions.


You may notice white fluffy mould in the HOTBIN, this is nothing to be concerned about and is actually an indicator that actinomycetes (a fungus-like bacterium) are present in your HOTBIN.

Actinomycetes help digest and break down plant material, ordinarily their presence is a good indication that the tough fibrous material in the HOTBIN is being successfully decomposed and the bacterium is helping to create a well-balanced compost which is a rich, deep brown in colour and contributes towards a noticeable “earthy” odour.

The presence of actinomycetes is usually associated with the addition of grass and tougher fibrous materials in damp, warm conditions. Actinomycetes are especially effective in dealing with lignin associated with newspapers and woody materials and cellulose found in plants.


It is a type of fungi found in 95% of all vascular plant root systems. It acts symbiotically with plant roots - the plant provides sugar/carbon to the fungus and in return the fungi transfer nutrients and water to the plant roots. The white hypae have a vast surface area and hence uptake network for nutrients. The white appearance should not be confused with white decomposing fungi - they have totally different roles in the soil eco-system.

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