Visit to River Valley Ranch’s Mushroom Farm

Two car­loads of Local Foods employ­ees hit the road on a pleas­ant day in ear­ly May to Riv­er Val­ley Ranch, locat­ed in Burling­ton, WI. Our first stop was the farm store, estab­lished short­ly after the farm began in the late 70’s. We perused shelves filled with local pro­duce, unique dried goods, and sam­ples of Riv­er Valley’s sig­na­ture dips and sauces, made right on the farm.

Estab­lished in 1976 by Bill Rose, Riv­er Val­ley Ranch has seen many ups and downs. Some moments were won­der­ful, and some were trag­ic. Read more on that his­to­ry on their site.

After perus­ing the store for a bit, we met Eric Rose, cur­rent own­er and son of Bill, who led us on a tour of the facil­i­ty. The mush­rooms are grown in a series of arched-roof build­ings con­nect­ed by a long hall­way on one end.

It all begins, as most things do, with com­post. A mix of manure, straw and min­er­als cre­ates a fer­tile foun­da­tion.

Riv­er Val­ley is work­ing on a new com­post­ing struc­ture, which includes slats below that allow for air to flow through the com­post. This sim­ple change speeds the rate at which com­post reach­es peak con­di­tions for being trans­ferred.

If you jumped into this com­post heap, you would want to quick­ly escape, as tem­per­a­tures inside reach 180° Fahren­heit. The bac­te­ria in the manure con­sumes the sug­ars from the hay in a process Eric described as “carameliz­ing” — which essen­tial­ly pas­teur­izes the com­post. It’s good for sniff­ing.

When the com­post is ready, myceli­um, a sort of “root­stock” for mush­rooms, is intro­duced and mixed in. Large beds are then filled with the com­post and myceli­um mix­ture, then stored in high-tem­per­a­ture rooms where the myceli­um col­o­nizes the com­post and sets the stage for mush­room growth.

The beds are then moved into the long build­ings, where cool tem­per­a­tures and high humid­i­ty encour­age mush­room growth. Har­vesters then work their way through the beds each day, pick­ing right-size mush­rooms at a rate of about 15,000 lb per week. Remark­ably, the room pic­tured below goes through a full cycle of “first flush” growth through the end of its life cycle in less than 3 weeks.

Beds of crem­i­ni mush­rooms grow­ing at Riv­er Val­ley in Burling­ton, WI

Here’s an inter­est­ing sto­ry from the farm’s his­to­ry: they start­ed grow­ing por­to­bel­los com­plete­ly by acci­dent! One day in the mid­dle of the sum­mer of 1990, the AC unit used to cool the crem­i­ni mush­room house shut down. Crem­i­ni mush­rooms are actu­al­ly baby ver­sions of por­to­bel­los — and when the AC cut out, mush­room growth accel­er­at­ed quick­ly. Instead of throw­ing away the giant mush­rooms, Eric took them to the farm­ers’ mar­ket. After land­ing a spot in the news­pa­per, sales picked up, and he’s nev­er looked back!

We’re proud to work with Riv­er Val­ley! If you have any ques­tions about mush­rooms or how they’re grown, give me a shout.