The raw materials used in the Irish mushroom growing sector are nearly wholly of local origin - contrary to the situation in the Netherlands. All the raw materials come from Ireland, so Irish mushrooms truly are a national product! Eire and Northern Ireland being an island naturally raises the threshold to import cheaper raw materials from elsewhere, but it is still quite extraordinary that all the various components needed to grow mushrooms are present on this relatively small land mass. This makes it quite interesting to examine and compare the various raw materials with those common in the Netherlands.

The basic materials for compost in Ireland are wheat straw, chicken manure and gypsum. Other types of straw are used occasionally, and sometimes horse manure but not on a large scale. Ireland has 10 compost companies of which Walsh, Monaghan, Carbury and McGeary are the largest. Walsh and Carbury produce phase, 2 and phase 3 compost, Monaghan and McGeary only phase 1 and 2.  Monaghan also cooperates with Carbury so it can also offer phase 3 compost.

Straw

Irish straw is of excellent quality. The heavy rainfall in Ireland, combined with the unusually warm summer of 2003 (however, with temperatures below those registered on the mainland), make the current Irish straw good and long in structure, with enough nutrients and in good supply. This has been so in fact for many years now: most composters only started using straw from the 2003 growing season in January or February 2004. This means fewer changes for growers, as the ‘new’ straw is already six months old at this stage and no longer as hard and fresh.

A little more care could possibly be paid to the way straw is stored: most of it is left lying outside so quite a lot of wastage is due to rotting caused by rain.

As horse manure isn't used, the compost often has a better structure than the Dutch. As cultivation mainly takes place in bags or packages, this is essential anyway.

Chicken manure and gypsum

The chicken manure is reasonably good in quality. Broilers are also raised in Ireland, in large enough quantities to satisfy the demand from composters for manure. The manure is usually based on wood shavings or chopped straw.

The quality of the chicken manure fluctuates wildly. The moisture content is also usually on the high side (more than 40%) which means composters have their work cut out to make the manure fine and spreadable. This is done with manure spreaders or special shovels. The chicken manure is already mixed with gypsum to make it easier to spread and to neutralize the greasy components. The nitrogen content is often lower than in the Netherlands, around 4-4,5 %.

So as not to use too much chicken manure, which could make the compost too greasy, urea or ammonium sulphate is often added. These additions are however never more than 5-10 % of the total nitrogen needed in the compost.

Contrary to in the Netherlands, the gypsum is usually natural in origin, so has a pH of 7. This contributes to a higher PH in the compost, at inoculation 7.5.

Taking everything into account, Irish compost is good quality. There are naturally differences from company to company, but on average the structure is superior to that in the Netherlands. Fermentation takes place for longer as the cultivation process is somewhat different in Ireland. (bags/packages) The compost price is higher too. Not using horse manure and the small composting facilities means that a ton of compost ready for inoculation costs the same in Ireland as a ton of incubated compost in the Netherlands, around 130 to 140 euros.

Spawn

Since Sylvan took over the Irish International Spawn Laboratory (ISL), Sylvan also has its own factory with V-blender in Ireland. Various strains are produced here locally. The other major spawn manufacturers such as Amycel, Italspawn and Le Lion are also represented in Ireland. It's a noteworthy fact that virtually without exception in Ireland the white intermediate hybrids are grown, such as A15, 130, 737 and Delta. This is probably due to these strains being very easy growers with good yields. Large hybrids are more difficult to cultivate under Irish conditions, as the growing rooms or tunnels have less flexibility regarding climate control and the compost in general has a lower quality.

Chestnut mushrooms are quite a rarity in Ireland. Nearly all the production is destined for the UK market, with a wide range of packaging formats and grades for the white mushrooms, ranging from baby buttons (very small and fine grade) to flats (large, open, stemless mushrooms).

Irish growers don't always know - or for that matter care - what they have in their growing rooms as long as it's an intermediate hybrid. The differences between for example A15 and 737, a subject Dutch growers can discuss for hours, are often considered unimportant in Ireland. This explains why it's often the compost companies that decide, or switch between two varieties each week for safety reasons.

Casing soil

Peat is in abundance in Ireland. Peat, and mushrooms, are two of the country's major exports. This ensures that casing soil can easily be produced locally. However, as Irish peat mainly comprises younger, lighter types, Irish casing soil companies are unable to produce a product that is as heavy and wet as in the Netherlands. This would be undesirable for the Irish methods anyway, as casing soil is placed by hand in the bags or packages. But as increasing numbers of growers are switching to Dutch techniques with shelving and mechanization, the demand for heavier casing soil is rising accordingly. For the (numerous) casing soil companies, quality is becoming more important, but so long Irish raw materials are used, it will be impossible to manufacture much heavier casing soil.

Climate

The Irish climate is every grower's dream: In the winter with average temperatures of around 5 degrees Celsius, and in the summer 15 degrees (so it's hardly surprising the fair Irish resemble cooked lobsters on the beaches of the Spanish Costas during the summer!).

This climate eliminates the need for investments in climate installations for extreme conditions. The areas used for growing can be kept simple and basic, with some heating and mobile cooling systems. The weather is also favourable for compost production: cool and windy, with good substance exchange. In this sense, it's a pity for the many composters that government regulations are slowly forcing them to move indoors.

Here lies precisely the greatest challenge now facing the Irish mushroom industry: reducing emissions of ammonia and sulphur compounds to 0, as current practice in the Netherlands. This process is expected to involve a huge amount of time ,money and effort and that at a time when prices are already under heavy pressure from Dutch and Polish competition. But Ireland's abundant natural resources, in all respects, ensure the country will continue to play a major role in international mushroom growing.