Custom Compost

Our substrate manufacturing facility in Co. Wexford has set the standard others aspire to. We are continually expanding and investing heavily in this state-of-the-art facility, ensuring our Irish growers have unbroken availability of high quality substrate and cementing our position as one of the largest and most reliable businesses in the mushroom industry.

Custom Compost is the mushroom substrate production facility for the groups Irish operations. Trading began in 1980 selling phase 2 mushroom substrate and from 1995 to date we have invested heavily to become the first exclusively-bulk phase 3 mushroom substrate supplier in Ireland. We are highly acclaimed to be one of the most modern, technically advanced and environmentally friendly mushroom substrate production facilities in Ireland and the UK.

Production is currently 1,800 tonnes per week of exclusively-bulk phase 3 substrate delivered to our mushroom growers/customer base. A fleet of 12 new bulk walking-floor trailers was procured from 1999 through 2012 at a cost of approximately €1 million to allow us to achieve this.

The facility was licensed by the Environmental Protection Agency (EPA), Registration No. W0-123-01 from October 2005 until August 2011. Due to changes in the European Waste Framework Directive, current regulation is under the Department of Agriculture, Food and the Marine (DAFM) and the appropriate Local Authority is Wexford County Council. We are also product compliant under the Bord Bia Mushroom Substrate Standard.

Phase 1

Having pioneered aerated bunker substrate production in Ireland in 1995 we were market leaders again in 1999 with the first fully enclosed indoor aerated substrate tunnels combined with exhausting emissions at height. This was further enhanced by an overhead filling system to generate a very uniform mix of material, which in turn leads to homogenous, consistent, high performing, quality mushroom substrate on which we are proud to have built our reputation.

During 2008 the balance of the substrate production process was enclosed and an exhaust stack of 40 metres was erected. This project constituted €1.5 million of environmental expenditure and is further evidence of our environmental credentials.

Phase 2

Our phase 2 tunnel facilities are state of the art, purpose built & computer controlled. These are carefully managed under a rigorous hygiene programme delivering clean, selective and consistent mushroom substrate.

The spawn, or mushroom seed, is added under thoroughly clean conditions in an enclosed spawning hall with an over-pressure system to maintain optimum hygienic conditions which is of paramount importance.

After the spawn has been added to the substrate it is transferred to our phase 3 tunnel facilities.

Phase 3

Our phase 3 tunnel facilities are similar to phase 2 - state of the art, purpose built and computer controlled. Spawn growth, or ''spawn running'', is managed at optimum environmental conditions for a duration of 16-19 days.

This means a process duration of approximately 6 weeks from initial mixing of raw materials in phase 1 to finished phase 3 mushroom substrate.

Product List


Unit Size

Supplement Included


Phase 3


20-25 Tonnes


All of Ireland


Full substrate analysis is issued post delivery.

Prices vary according to load size and distance and can be quoted on request.

We operate our own fleet of modern trucks, complemented by local contract hauliers. All deliveries are operated by fully enclosed automated bulk delivery systems. Substrate can be delivered to any location in Ireland.

Technical Back Up and Sales

Our Technical Team is available at all times to give full back up and any support that may be required. Not only advising on the substrate but also on the full range of disciplines that are required from growing, picking and hygiene to managing the crop to its full profit potential.

Please contact our Custom Compost office for more details.