Home-Grown Oysters

Move over shiitakes, you fancy, reputedly healthful mushrooms offered on supermarket shelves and at farmers’ markets at high prices. Make way for oyster mushrooms.

Many of us have chosen to grow shiitakes rather than pay the high prices for them. This means laying in a stock of freshly cut hardwood logs and riddling them with holes that are plugged with inoculated dowels pieces, then sealed with wax. A dose of patience is also needed for home-grown shiitakes, even after going through all that trouble, because a year is needed until first harvest.

My logs, from two and three years ago, yielded mushrooms last spring and autumn. But those logs are sleeping now; what about mushrooms now?Shiitake logs

Enter oyster mushrooms. Oyster mushrooms are much more cosmopolitan about their nourishment. And planted now, harvest could begin within a few weeks.

The basics of growing any mushroom are the same. You inoculate a substrate (some material high in cellulose) with purchased or home-grown mushroom spawn. Fungal threads colonize the substrate and then, after a certain amount of time or in response to some stimulation, such as being dunked in water, mushrooms pop out of the surface of the substrate. In between short rests, they’ll pop out repeatedly until the substrate is exhausted. Then you start again with a new inoculation.

Toilet Paper Mushrooms!?

A few years ago, I grew oyster mushrooms on nothing more than a fresh roll of toilet paper, which provided a conveniently configured source of cellulose. I got the spawn for inoculation from Field & Forest Products (their TeePee™ kit). All that’s needed is to pour boiling water over a roll of fresh toilet paper, let excess water drain off, then put the roll into the plastic bag that is provided.

I inoculated, as directed by filling the center tube with the mushroom spawn and sealed the bag closed. Every once in a while I opened the bag to mist the inside with water, and watch the fungus grow its way out into the paper. After colonization is complete, mushrooms started popping up from the top of the roll.

Okay, my wife did express some aversion to eating food growing out of toilet paper. And the whole setup, admittedly, is not really all that attractive.

Coffee Grounds, Another Substrate

Not to give up on winter mushrooms, I could try growing oyster mushrooms on another readily available substrate: coffee grounds, a waste product from coffee shops, bakeries, and fast food joints. I also remember a previous foray into “espresso mushrooms” a few years ago. The Pohu strain of oyster mushrooms are among the best for coffee grounds.

To inoculate, you just break up and mix the spawn, a compressed mass mixed with sawdust, with (clean) hands and/or a knife in with the coffee grounds. The mixture then goes into a (clean) bucket having drainage holes, which, after a thorough watering, is covered with the plastic bag

After sitting in a bright location and misted daily, the coffee grounds becomes covered with  fuzzy, white fungal threads. Within a few weeks, fat mushrooms swell up from the substrate, ready for harvest when their caps become just concave.

In my previous experience with espresso mushrooms, I remember an invasion of fruit flies having a field day on and in the coffee grounds. Or were they fungus gnats? Avoiding overwatering should keep fungus gnats in check, and fruit fly season is past, so espresso mushrooms are worth another try.

The nice thing about growing oyster mushrooms on coffee grounds is that there’s no need to purchase new spawn when production slows. A nice chunk of the exhausted coffee grounds can be used to inoculate some fresh grounds.

The cleaner everything that comes into contact with the spawn and the substrate right from the start, the less chance for contamination and the longer the process can be kept going. It can become an indoor game, to see how many oyster mushroom cycles can be grown before new spawn is needed again. In addition, of course, there’ll be some tasty harvests.

An Early Spring, For Shiitakes

Now that I think of it, I could be sitting down to a meal with fresh shiitakes — just fool some logs into thinking it’s spring. Which it is, in my greenhouse. I’ll move a couple of logs in there, where I’ll bet the warmth and high humidity will soon pop out some mushrooms.


  1. Gary
    Posted March 9, 2017 at 11:31 am | Permalink

    Lee, you and your readers might enjoy “Organic Mushroom Farming and Mycoremediation: Simple to Advanced and Experimental Techniques for Indoor and Outdoor Cultivation” by Tradd Cotter. Much more accessible than it sounds, it explains how to grow a wide variety of mushrooms at home or commercially. He even gives hints on how to collect spoors from the grocery store.

  2. Kathy
    Posted March 10, 2017 at 8:28 am | Permalink

    I tried growing mushrooms with a Back to Roots kit. Very easy and much more attractive than toilet paper LOL. I am cautionary about the logs because well, natural other funguses may grow on them that are not edible? How do you avoid that? Only harvest from the plugs?

    • Posted March 11, 2017 at 4:49 pm | Permalink

      With appropriate tree species, fresh logs, and inoculation according to directions, weed fungi should not be a problem. I’ve never seen them. It also helps to be able to identify the edible fungus that does grow.

    • Becky P.
      Posted March 12, 2017 at 4:14 pm | Permalink

      Kathy, Lee’s right that learning to identify species that look like the mushroom you’re trying to grow will help you feel more comfortable cultivating them. But it’s also unlikely that any competing fungi will look so similar and grow so prolifically as to be confusing. If you use fresh-cut logs (it’s best to cut trees in the spring, after the sap has returned to the wood), wait a couple of weeks to plug them (so that the tree’s natural anti-fungal compounds have a chance to degrade), plug them densely enough to give the preferred fungus an advantage, and don’t let them get so dry that the fungus dies – you’re creating conditions under which not much else can flourish.

      You’ll also learn to recognize the signs of success as you cultivate your mushrooms, too. For example, if you’re growing shiitake on logs, you’ll be able so see the progress of its white mycelium from the outer edge of the cut ends of the logs to the inside. Once it’s colonized most of the log, it’ll be ready to fruit. No fungus is going to be able to fruit prolifically without colonizing the log, and you’ll be able to see signs of that competition happening long before it does. The mushrooms will emerge from all over the log, too, usually first at splits in the bark. Give it a try! Like Lee said, it takes a while to see the fruits of your labor, but if you have some tree trimming to do anyway, it’s a nice way to use the wood.

  3. Becky P.
    Posted March 12, 2017 at 3:55 pm | Permalink

    Lee, I recently discovered your blog and books, and I wanted to tell you how much I appreciate them! I haven’t had much success with oysters on coffee grounds either, though I think my issue was that the level of the substrate was too far below the top of the bucket. Only a few clusters of mushrooms emerged, and they grew long and spindly stipes with small caps. Maybe I’ll give it another try, too.

    Have you ever tried cultivating any mushrooms outside?

    • Posted March 13, 2017 at 11:43 am | Permalink

      I once tried strophalaria in mulch, but it was a dry spring and had so many plants to water that I could bring myself to watering mulch (with strophalaria inoculum). I may try stropholaria again this spring, in shade.

      • Becky P.
        Posted March 13, 2017 at 12:00 pm | Permalink

        Good luck! I tried the same species outdoors one year and failed to consider just how frequently I’d need to water it – next time I’ll try putting the patch closer to the water hose.

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