Instructions for Portobello and White Button Mushrooms

Our mushroom spawn (seed) is impregnated onto grains, for sowing in homemade or shop bought mushroom compost (not spent compost). The spawn will produce for about 6-12 months depending on conditions. 

Instructions to make the compost:

For 50 grams (2 ounces) of spawn you will need 5 lbs of fresh horse manure (max 30 days old). Indoors, mix 20% clean straw to the manure which previously had been left in a wet heap for two weeks. This will help it break down better. Wet the compost well and form a mound. After a few hours the temperature will increase.

After four days, break down the heap and form three to four smaller heaps. This will help aerate the compost. The heaps should be turned weekly until the temperature stops rising (you will probably have to turn it 3-4 times). Wet any dry patches when you turn the heaps. The compost will appear dark brown in color, soft without any bad or ammonia smells. Squeezed between your fingers, a few drops of water should come out. The compost will be alkaline (PH 7.2 – 7.4).

Sprinkle the heap with the crumbled spawn, pushing it down deep with your fingers and cover it. 

After about two weeks, a white mold will form. Put the sown compost in containers, trays, soil or gabs, press and cover the compost with 4-5 cm (2-2 ½ inches) of 4 parts peat, 2 parts very fine gravel and 1 part lime (calcium carbonate) mixed well together. Keep the earth damp but not wet.

In about 20-30 days you will see the first mushrooms appear. The compost can also be sown under shady grass on your lawn.