Following on from learning about mushroom spores in our last issue, our resident mycologist, John Robinson, introduces us to the rich and varied Oyster mushroom. Perfect for beginners, this fungi beast produces some of the best yields in the world of cultivated fungi. Bring it on!!

Oyster mushrooms are a large, diverse and colorful group of mushrooms. They are found all over the world and can range in color from white and grey right through to blue, yellow and even bright pink!

Commercial cultivation in bags of straw hung from the ceiling.

Oysters are the easiest mushrooms to grow and can use a wide range of agricultural wastes as food – from straw and woodchips to sugarcane and coffee. I know of one coffee distributor in Great Britain who collects used coffee grounds from the restaurants he supplies and then uses it to produce many pounds of mushrooms per day. You can even grow them on books, phone directories and toilet rolls.

Oyster mushrooms are a good place to start if you are interested in growing your own as the raw materials are cheap and the mycelia grow so quickly that contamination has little time to take hold. Yields are among the best of all cultivated fungi.

A few of the most interesting oyster mushrooms are discussed below.

Tree Oyster or Blue Oyster (Pleurotus ostreatus)

Young blue oyster mushrooms.

This is the classic oyster that has long been a favorite with mushroom hunters for years! Wild specimens have been found weighing 44 lbs (20 kg) and nearly 10 feet (three meters) in circumference! They are easy to grow on straw and are prolific producers. Many cultivated mushrooms suffer from pests called nematodes, which are like small worms that can feed off and damage the mushroom mycelium. No such problem for P.ostreatus – it has been shown to secrete a metabolite that stuns the nematode. The mushroom mycelium then invades the helpless nematode and quickly consumes its internal organs. That’s a mean mushroom!

The Golden Oyster (Pleurotus citrinopileatus)

One of the most spectacular of all fungi – with clusters of bright yellow to golden caps. It can have quite a bitter taste when fresh and is best when thoroughly cooked.

Golden Oyster mushrooms.

The Pink Oyster (Pleurotus djamor)

Probably the fastest growing of them all, this tropical species produces brilliant pink fruits. Not regarded as the best tasting of the group, it does however have a place, especially in developing countries as it can be grown without the need for much equipment.

Pink Oyster mushrooms.

The King Oyster mushroom

This is the oyster mushroom with the best flavor. Much more commonly seen in markets in Europe, it can be collected from the wild or grown on tree stumps or straw outdoors or indoors. It has thick solid stems and keeps very well after harvest.

Commercial cultivation of King Oyster mushrooms in bags.

The King Tuber Oyster mushroom (Pleurotus tuberregium)

This is an unusual species that forms a large tuber called a sclerotia or “truffle” (which looks a bit like a kind of large alien egg). These “eggs” can then be planted in sand and large mushrooms sprout directly from them.

Cultivation

All of the species above can be done at home using a similar method. Initially the mushroom is grown on grain that is then used to inoculate straw or a similar substrate, which has been heated in a hot water bath (“pasteurized”) and allowed to cool. The straw is loosely packed into bags and rapidly becomes covered in mushroom mycelium. Holes are then punched into the bags and mushrooms appear in abundance! You will be astounded at the amount of fungi you can produce – so give it a go!

Inspired to have some fungi? Still got some questions you need answering? Join the discussion and post your thoughts below!