How We Grow Happy Happy Mushrooms

by Hayley Kats

louis with a giant oyster mushroom

Who are you, how long have you been at Smallhold for?

My name’s Louis Vassar Semanchik and I head our R&D program. I joined Smallhold in April 2018 as farm technician, back when we just had a few Minifarms in operation.

How did you get into growing mushrooms? 

I grew up in the garden so getting into farming was a natural progression for me. In college, I was involved in food justice organizing and when a friend approached me to start a mushroom farm I jumped on the opportunity.  As I cultivated mushrooms, I realized how healing they can be [both socially and environmentally], so in the spirit of food justice, it was a natural fit.  After that farm, I helped operate a few controlled environment operations around the country before returning to NY to start with Smallhold.

What types of things do you do in R + D?

Right now, R&D’s focus is on developing improved growing methods for our current mushroom varieties as well as testing new varieties. Testing how the mushrooms react to different parameters like light exposure, humidity, temperature, and fresh air exchange levels results in the creation of climate recipes. "Climate recipes" are time series of environmental conditions that change as the mushrooms progress through their grow cycle.

Generally, mushrooms enjoy a slightly warmer, wetter environment as they start to pin [form baby mushrooms], and as they mature we tend to gradually drop the temperature and humidity. Keying into the optimal set points along their grow cycle is a large part of our testing. Our goal is to grow happy mushrooms, and happy mushrooms grow beautifully large yields, quickly, with little to no contamination. We work closely with the engineering team to develop these recipes, test different climate control equipment that allows us to better mimic natural weather patterns the mushrooms are used to, and develop the user interface our farmers use to control the grow chambers.


mushrooms that are deprived of oxygen

These oysters didn't receive enough oxygen.


What is FarmLinc?

The FarmLinc is the computer onboard used in our climate-controlled grow chambers. It senses the temperature, humidity, and oxygen levels in our farm and reacts to keep the climate in balance for the given variety of mushroom. It also provides historical data for us to assess and correlate with crop performance. It is named after the late Gary Lincoff, a prominent mycologist and educator that was based in NY (RIP Gary!).


brandy, our minifarm

Brandy, one of our first Minifarms. We still use her for tests to this day.


What is the process like for vetting new mushroom species to grow? 

We approach new varieties that we think people would get excited about. Then we conduct a literature review to see what the current successful methods (if any!) before experimenting with growing them ourselves. The four main metrics that we use to vet a given variety before launching on our farm is: yield per pound of substrate, contamination rate, grow time, and number of substrate blocks that fit in a chamber. If these are favorable and the initial cultivation tests work out we will scale up the trials, develop the packaging, and eventually plan our launch into commercial production.

How does one start trying out new mushroom species?

The first step is to understand its natural life cycle. Where does it naturally grow and during which season? What material does it naturally grow on? What other organisms are present that may be playing an important role in the fungus’ life? Once these questions are answered, it becomes obvious that some mushrooms are vastly easier to grow than others. Saprophytic fungi are those that eat dead organic matter [all of our mushrooms are saprophytic!] and the cultivation process is figuring out what substrate materials and climate conditions result in the best growth. Some varieties, like oyster mushrooms, are voracious generalists that will grow on a variety of substrates and in a variety of conditions. Some shiitake strains require a ‘cold shock’, where the mycelium is put in cold water or a refrigerator before fruiting to mimic the experience of winter. It is amazing how complex some mushrooms’ life cycles can be. Take mycorrhizal varieties of mushrooms, which form a symbiosis with the roots of trees. Because of this mutual exchange of nutrients they have with the tree, they are much harder to cultivate. These include truffles, chanterelles, and most species of morels. 

What has been one of the most challenging species to cultivate?

Each variety has their personalities and trouble areas. Maitake have proven to be a challenge because of their long grow time and sensitivity to disturbance. Because they are a polypore, their grow cycle is 3 times as long a blue oyster. It takes 30-40 days for the mushroom to grow from the moment pinning is initiated, so if humidity or temperature gets out of range within that time for more than a few hours, the whole crop is at risk of aborting [meaning the mycelium quits sending energy to grow the mushroom and it begins to wither].


maitake mushrooms

A beautiful maitake cluster. 


What are some mushroom species you are hoping to grow in the future?

We love to hear from you all – what varieties would you like to see? I like to keep people guessing on what we have in store, but I will say I’m excited by varieties we haven’t yet seen successfully cultivated.