Farm Tour: Growing Mushrooms

I went on a CUESA-organized farm tour last Sunday to Monterey County, about 2 hours south of San Francisco. Our first stop was Far West Fungi in Moss Landing, just a few miles from the Pacific Ocean. The Moss Landing area is close to Salinas, the lettuce bowl of America, and is a mix of moderately-sized industrial farmland–monocultures stretching across wide swaths of land; strawberries here, brussels sprouts there, lettuce over there–and smaller operations like Far West Fungi and our second stop, Yrena farm (which I will write about another week).Far West Fungi sells their mushrooms at several farmers markets in the San Francisco area and has a shop in the San Francisco Ferry Building marketplace.

Upon disembarking from the bus, “farm” was not the first thought that popped into my head. “Abandoned military base” or “the set of a grade-B horror movie” (“Hey everybody! Let’s all go play spin the bottle in that creaky building with the red splotches on the door!”) seemed like better descriptions. But the facility does what it needs to do–provide temperature and humidity control–as the high quality of the Far West’s product illustrates.

Our tour guides were John and Toby Garrone, the current owners of the company. Although John has a long history in the food business, he got into mushrooms almost by accident. While working as a police dispatcher in San Francisco in the 1980s, John met someone who was starting a mushroom farm in southeast San Francisco, near the Hunters Point Naval Shipyard.

Growing Mushrooms is a Multi-Step Process

Growing mushrooms is a multi-step process, with plenty of waiting between some of the steps. I’ll go through the process, as explained to us on the tour, most likely missing some details here and there.

Pile of growing medium at Far West Fungi mushroom farm
Pile of growing medium

1) Preparing the mushroom growing medium

One of the most important raw materials for mushroom cultivation is a growing medium. Far West Fungi is certified organic, so they have strict requirements for their material. They are fortunate to have an agreement with a nearby cabinet and door maker who supplies red oak sawdust (in huge quantities, as the photo to the left illustrates). After arrival on site, the dust ages for 12 weeks to make a suitable bed for the mushroom culture (something happens as it ages to make it “right”). The final growing medium is a mixture of the aged saw dust, oyster shells (or another source of calcium) and rice bran. On a normal day, the company’s workers fill about 3000 gallon-sized plastic bags per day.After filling a bag with the growing medium, it is placed on a cart, which is then rolled over to the sterilization area.

2) Sterilizing

This step, and the next one, is where growing mushrooms looks more like a science experiment than farming.The cart from step 1 is rolled into a large autoclave that has a door on each side (photo right). After a period of heating and cooling, the cart is wheeled though the door on the other side to the “clean room.”

Sterilizing chamber at Far West Fungi mushroom farm
Sterilizing chamber

3) Starting the mushroom culture

The fungal culture is grown on a petri dish in the clean room. When the culture is mature, it is divided among ten 2-liter-sized flasks that are filled with the growing medium. These flasks remain in the clean room while the mycellium (the “roots” of the fungus) grows to fill the flask. Next, the flask’s contents are divided among one hundredd bags filled with growing medium. When the bag contents are mature, the contents of each bag are split between ten bags. Thus, one petri dish ends up supplying life to 10,000 bags.

4) Incubating

The bags go through two stages of incubation, each about 30 days long (shiitake, however, need 60 days of secondary incubation). During these two periods, the mycellium digests the growing medium and fills all available space, turning the color of the bag contents turn from a deep brown to nearly pure white.

Incubation room at Far West Fungi mushroom farm
Incubation room

5) Growing Mushrooms

After incubation, the bags are moved to the growing rooms. The wood-digesting mushrooms grown by Far West Fungi need light, so a few fluorescent lamps are always turned on. They also need moisture, resulting in periodic blasts of water mist.At this stage, the bags are finally opened up–either with one end sliced open or with a small plastic collar installed around a hole in the bag (the collar directs the growth of the mushrooms into a cluster that is more easily harvested and more attractive).

Oyster mushrooms in a growing room at Far West Fungi mushroom farm
Oyster mushrooms in a growing room

6) Harvesting Mushrooms

Once a day, harvesters walk though the growing rooms to cut off bunches that are ready for sale. The mycellium in each bag goes through one “fruiting” before it runs out of growing power.

7) Cleaning up

Once the harvest is complete, the growers are left with a plastic bag filled with mycellium, the remnants of oyster shells, rice bran and sawdust. This material is sent to a nearby compost company to be converted to fertilizer (which is especially good for orchards, according to John Garrone).

A field of oyster mushrooms at Far West Fungi mushroom farm
A field of oyster mushrooms

A Few Final Notes on Mushroom Growing 

One of the things I realized during the tour is that Far West Fungi’s facilities don’t need to be in such a rural area. I noticed few, if any, unpleasant odors (the shiitake growing room had a rather pleasant aroma). It was hard to judge how much noise the facility makes, however, because the sterilization machine was not running (it’s powered by a steam boiler, which probably makes all kinds of hissing noises). Therefore, it is conceivable that a parking garage, or office building, or even a grocery store could be built with a mushroom-growing facility underneath. Has such siting been attempted anywhere?

Another description of the tour

Jen Maiser (author of the now-defunct Life Begins at 30 blog) was also on the tour and wrote about her experiences (with much better photos) at Bay Area Bites.

(A slightly different version was cross-posted at Ethicurean)


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