Growing Mushrooms

Air Date: Week of March 6, 1998

CURWOOD: This is Living on Earth. I'm Steve Curwood.

It's the middle of winter and there are many dark and gloomy days, not so good for gardening, except well, Michael Weishan, Living on Earth's expert gardener, has some ideas. What can you do when the days are dark and gloomy?

WEISHAN: Well, what I'd like to do is grow some mushrooms.

CURWOOD: Mushrooms?

WEISHAN: Absolutely. We have some shiitake mushroom kits. I'll bring them over here from under the bench.

(A box being moved; crackling of cellophane)

WEISHAN: This is actually the mushroom kit as it comes.

CURWOOD: So what's in it?

WEISHAN: Originally, it was sawdust and shiitake mushroom spawn, that's now sort of grown through it and knitted the sawdust into a sort of a spongy hole.

CURWOOD: Mushroom spawn? I mean, this sounds like something from a horror movie.

WEISHAN: (Laughs) Yeah, it does actually. Most of the mushroom is not what we actually think of as the mushroom. The main part of the mushroom plant is called the mycelium. And it's what we refer to as the spawn. It's a perennial part of the plant that grows underground. Its primary purpose is to decompose organic material. It has a specialized cell structure that creeps in between organic material and breaks down rotting dead organic matter. And that's the main part of the mushroom organism. What we call a mushroom is, the cap is actually the fruit body, the flower as it were, of the mushroom.

CURWOOD: Now, the sawdust adds the organic matter, is that it?

WEISHAN: Yes. The sawdust adds the organic matter, and different types of mushrooms grow in different properties. They've all been genetically bred over the millennia to break down specific organisms. Shiitake breaks down wood. The white button mushroom, for instance, that you see that's so common in the store feeds on compost and manure. Each one decomposes a slightly different aspect of the environment. The mycelium, the base of the mushroom, is actually exceedingly common in nature. Estimates range that up to 10% of the forest floor biomass is actually this mushroom mycelium creeping underground really. It's there, but you just don't notice it's there.

CURWOOD: Is this how all the mushrooms we find in the stores are grown?

WEISHAN: Yes, actually, it is. And it's really rather a good thing. Because these days, a lot of the species are somewhat endangered, and the natural environments in which they're grown are rapidly being developed. So if we had to depend on the environment for mushroom culture, we would be in trouble. A lot of them are grown in caves, actually. Certain varieties of mushrooms, like the white button mushroom you see in the store, actually do grow in the dark. These shiitakes actually prefer a bit of light. They don't photosynthesize, but they prefer a lighted condition in order to grow and fruit. And of course, there are also specialized mushroom houses, where the majority of the commercial production takes place these days.

CURWOOD: But now, with this kit you have here, it seems that people really don't need a cave or a special house to grow their own mushroom.

WEISHAN: No, because of course this has all been prepared for you, and this is the glory of the thing. It looks totally foreign. The kids love it, you know. (Laughs) What is this thing? And it's actually very easy to use, and you can get kits for various kinds. For shiitake, for oyster mushrooms, which are a delicious culinary treat. And they actually grow in coffee grounds, which is really cool, so if you have a lot of extra, if you're a big coffee drinker, you have a lot of extra coffee --

CURWOOD: (Laughs) Coffee grounds?

WEISHAN: Coffee grounds. Espresso grounds, I'm told, are especially palatable.

CURWOOD: Uh huh. Now, is it really cost-effective? I mean, is it expensive to get a kit?

WEISHAN: Well, let's put it this way. By the time you actually do this and harvest the mushrooms, the kits are about $20 a piece, generally. And they produce sometimes several, 2 to 3 pounds of mushrooms. So, it depends on what you can pay for organically-grown mushrooms in your part of the country, or whether you can even get them at all. The main part is educational. And it also shows you the value of the kit shows you how to actually grow this yourself.

CURWOOD: And I guess having mushroom kits is certainly well, safer than trying to go outside and finding wild mushrooms anyway, right?

WEISHAN: Yeah. Especially if you don't know what you're doing. Obviously, there is a danger of eating a poisonous variety. These will only grow what they're scheduled to grow. I think it's important, though, if you do this with kids, to stress that this is something that you do inside and that you then don't go eat every mushroom or fungi you see outside.

CURWOOD: What's your favorite?

WEISHAN: I happen to really like these shiitakes. That's my favorite. And also the oysters. I actually like all mushrooms. (Laughs) I've developed a taste. As a kid I never liked them at all, but now you put a mushroom in front of me and it's gone.

CURWOOD: Well, Michael, thanks for the info.

WEISHAN: Oh, my pleasure.

CURWOOD: Michael Weishan is editor of Traditional Gardening. When he's not digging in dirt or sawdust or whatever, he's happy to answer gardening questions. You can reach him at our Web site. The address is www.loe.org. That's www.loe.org.