To mark the Jahrestagung, the BDC (Bund Deutscher Champignon und Kulturpilzanbauer) and its guests visited the  A & L Pilzzucht mushroom farm in Nutteln, Germany on Saturday 30th October.

On the outskirts of this small village under the sunshine of Cloppenburg, three companies are located on a mini industrial estate. The middle company is the mushroom farm, currently the only agricultural enterprise on the estate. The farm visited in Nutteln is one of the two virtually identical A & L Pilzzucht farms owned by Michael Böging.

Both farms consist of six growing rooms with a growing surface of 500 square metres per room. They were built by Geraedts B.V. The farm in Calveslage dates from 1998 and the farm in Nutteln from 2000. 

The farm we visited is built from sandwich panels. Each growing room houses two rows of shelving with six beds per shelf. The beds are 30 metres long and 1.40 metres wide, while the growing rooms measure 6.40 metres wide, 4.50 metres high and 33 metres long. Each room is fitted with a climate unit, regulated by a Fancom climate computer.

Cooling is carried out by a mechanical cold water system with a total cooling capacity of 234 kW provided by a German supplier. A Viessmann heating boiler with a capacity of 285 KW heats the growing rooms and other areas. Humidity and cook out are done by a Viessmann steam boiler with a 285 kW capacity.

Method

Cultivation follows a five week schedule, with two flushes harvested manually. Once every five weeks the two growing rooms are filled. One on Tuesday - the regular filling day, and one on Friday. The ideal filling weight is 90 kg/m2 with plastic under the compost and 1,35 kg/m2 supplement of Champfood C. The incubated compost originates from Substratwerk Gartherheide. Compost is still made traditionally outdoors using 100% straw. The spawn is type A15. Euroveen supplies the casing soil type Carbo 8 with moisture number eight. Ruffling follows eight days after the mycelium has been allowed to colonize the casing soil, with 15 to 20 litres of water per square metre being sprayed. After around 24 to 36 hours recovery, blow down starts. The air temperature drops in five to six days from 21 degrees Celsius to 18 degrees Celsius. The CO2 content is reduced in this period in stages from 4500 ppm to 2000 ppm. During the pinheading phase a further reduction follows to 1200 ppm.

On Monday / Tuesday harvesting the first flush begins. Before the first flush is picked 2 litres of water is sprayed on Saturday and Sunday. After the first flush 5 to 7 litres of water per square metre is applied in sessions of 1 litre per square metre depending on the moisture content of the casing soil. The yield of the first flush is between 13 and 16 kg/m2. After the first flush no measures are required to limit the number of pieces. On the following Monday and Tuesday, the giants are picked in the second flush, then the middle and fine mushrooms. On the second flush 2 litres of water per square metre is sprayed once on the second or third picking day.

The two farms employ 45 pickers, including a group of part-timers. Yields from the second flush vary between 11 and 13 kg/m2. Average total production is 26 kg/m2 quality I mushrooms. Of the mushrooms picked, 35 % is graded fine, 62 % middle and 3 % giant. The mushrooms are sold to Weiße Köpfe Vertriebsgesellschaft.