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Controlled Environment Agriculture: Combining science and IoT integration for the perfect harvest

Grasses being grown in a controlled indoor environment with a glass ceiling

Controlled Environment Agriculture: the perfect recipe of traditional farming and IoT integration. What do you get when you mix farming techniques and knowledge with scientific data and intuitive IoT controls? Your best and most efficient harvest!

In this blog post, a transcription of our latest podcast conversation between host Phil Ruane and special guest Gretchen Schimelpfenig from the Resource Innovation Institute, we explore the applications and power of Controlled Environment Agriculture. Lighting controls for strong crops? Air quality controls for healthy plants and consumers? We’ll cover it all.

(The following is an excerpt from the Elevated Environments podcast.

Interview has been edited for clarity and length.)

Phil Ruane: You may have heard the news that the General Assembly of Virginia has passed a bill legalizing marijuana for commercial use, signed into law by Governor Ralph Northam. As of July 1, marijuana is legal for adults 21 and older to possess, consume and grow in Virginia. Effective in 2024, it will be legal to begin retail sales and it's going to be regulated by the Virginia Cannabis Control Authority. There's going to be a lot to figure out in terms of regulation and societal implications and all that stuff between now and then. One of the things that we have to figure out is how to grow and produce this stuff at a commercial level.

In February of this year I heard a talk from Gretchen Schimelpfenig of the Research Innovation Institute about controlled environment agriculture, one of multiple ways to grow marijuana. Her talk was fascinating. Controlled environment agriculture or CEA is an indoor agricultural method that gives you the ability to control the yield, light levels, and production times. It is by no means exclusive to marijuana. A lot of agricultural applications are employing CEA to boost yields, speed production, and manage the harvest more effectively. Because I found her talk to be so interesting, I invited Gretchen on to discuss the growing business, this emerging market, the architectural considerations involved and the best practices. Here is our discussion.

PR: Tell me a little bit about your organization, the Resource Innovation Institute. Who are the types of people that you serve, and what kind of services are you providing?

Gretchen Schimelpfenig: The Resource Innovation Institute is a nonprofit organization based in Portland, Oregon. We're a data driven, membership based association. We have members who are supply chain actors like architects, engineers, technology manufacturers, as well as folks who serve producers, like utilities and efficiency programs, or government agencies who are seeking to create policies that are sensible for this industry. We also work with producers, themselves. The services that we provide primarily serve those who grow plants and produce plant based products. We started in the cannabis industry, serving growers in the greenhouse and indoor growing markets, helping them understand how to benchmark their energy and water consumption, as well as learning the best practices for using the technologies that are being incentivized like LED lighting. So we've now expanded our work to serve folks who grow crops in all controlled environments through a USDA grant. That allows us to work with vegetable greenhouse producers doing the same sort of work: helping establish best practices, creating key performance indicators for resource efficiency and productivity, and then promulgating that into the market with trainings and recognition of excellence and case studies.

PR: That's really interesting. When I think of agriculture, I think of a large field and miles and miles of crops, crop dusting and all that sort of thing. Why would somebody choose a CEA type situation rather than just growing crops outdoors? Is it because some plants grow better indoors?

GS: Well, there's a number of reasons and factors you might consider when changing from field farming to incorporate some sort of mixed-light environment, or considering going from completely outdoors to completely indoors. There are a lot of growers who do a mix of all three or maybe choose a few. It depends on the crop, and it depends on where you are. I live in Vermont. A reason why growers have greenhouses in Vermont is to extend the growing season. Some plants- it's not that they grow better indoors, but they're able to grow indoors during certain times of year. Cannabis growers have been growing indoors due to stigma and regulation that didn't allow them to grow outdoors for a very long time. And many of them still have a sort of black heart market attitude and find that they can cultivate a very good crop indoors because that's what they've done this whole time. I would say that a lot of cannabis growers, for example, in California and Colorado, they're finding great success with greenhouse growing because it's got that special sweet spot between using some of the sun, and then also having the controlled environment that keeps out pests and pathogens and allows them to baby the plant a little bit more. So when a plant “grows better indoors,” it's that they're exposed to less adverse climate impacts. I know a grower in Oregon who is building a greenhouse that incorporates light deprivation. They're able to tailor that environment avoid the impacts of climate change, like large fires bringing particulates onto their crops. Vertical farms of leafy greens and other things are definitely enjoying growing indoors, too, because they're able to stack the plants one on top of the other and make great use of the expensive real estate.

PR: Wow, when I first heard your presentation, you were talking about lighting and "light recipes.” It's kind of the impact that a certain kind of light or a certain kind of nanometer has on crops. So what do you mean by light recipe and what's an example of one that works really well?

GS: If we go back to lighting science and think about photons as packets of energy coming out of a light fixture that can then hit the photo collector of a plant, i.e. a leaf, that is a type of light colored by what spectra that photon is from. You can have lots of photons and different portions of the light spectra that come out of a light. You might find that at Home Depot, they've got the daylight lights that have it seems a little more blue, right? It means that the light bulb is putting out more packets of blue photons than it is packets of orange. And if you go into a cannabis grow using a high pressure sodium light fixture, they're going to look a lot more yellow or orange. That means that they're getting a lot more from that part of the spectrum. And so when we talk about light recipes, we're really talking about honestly LED lighting alone, because it's the only light fixture that's capable of having a customizable light recipe. A high pressure sodium from one brand is going to have the same light recipe as a high pressure sodium from another. Whereas you can get a broad spectrum, or what you might call a white LED, that includes a lot of different photons from a lot of different portions of the spectrum. Alternatively, you might get a narrowband LED that focuses on a few portions of the red spectrum, a few portions of the blue and maybe some far red. To answer your question, light recipes can mean a lot of things, and it's a manufacturer term that doesn't have a scientific definition. But it's sort of like "what type of beans are they putting in the chili and that the plant is ultimately going to eat?"

Academic research that we’ve been gathering has shown that portions of the blue spectrum can affect photomorphogenesis, i.e. the structure of the plant, the color of the plant, and maybe the amount of energy that goes towards leaves and flowers versus the support structure. However, red portions of the spectra have more influence on yields. So that's something that can be incorporated more in the flowering stages of growth to induce greater production. It's still preliminary, and we're finding out a lot from the academics. They found that with higher blue in the red-to-blue ratio, lettuce decreased by up to 63% in its production of vegetative mass because it was focusing more on something else with when it was using that energy.

PR: That's wild! I know on the commercial side of the business, we are doing research that shows that a 490 nanometer can affect our circadian entrainment to greater levels then. So who would have thought that it would be the same for plants? That's amazing.

GS: Yeah, there are nanometers in the far red range that can wake up plants and put them to sleep. They've got their own circadian spectra that we can investigate now as well. And if you get really far out there, there's people who are even creating sub 24 hour days with lighting controls by putting their plants to sleep, convincing them that they've gotten enough light in 10 hours and then putting them to sleep, getting enough dark period, waking them up, and ultimately getting faster harvest cycles by using light spectra and light schedules.

PR: Wow, that's amazing. Yeah. Well it sounds like there are amazing things that you can do in controlled environment agriculture that you can't do outdoors. Is there an environmental impact? You mentioned greenhouse gases earlier. But is there some kind of environmental trade off, or are indoor agricultural environments more sustainable? Or less? Or about even?

GS: Well you're hitting at the heart of what RII is seeking to do with the market, which is to quantify the benefits and ultimately establish the best practices that result in getting benefits. Just like you can use an LED light really poorly in your house and keep it on all the time with no control whatsoever of your thermostat, with a high efficiency HVAC piece of equipment you can have growers using an indoor agricultural approach, but being wasteful with it. We want folks to understand the best stuff to buy and install, but then also how to operate it, commission it, and measure and verify its continuous improvement. So, quick answer: indoor agricultural environments are not more sustainable in the energy intensity.

If you think about how much energy is used per square foot, a field farm uses very little energy per field farm acre. If you think about a house as maybe 40 kilo BTUs per square foot per year, and then you think about maybe an office building at 100, hospital at 200, maybe a grocery store at 250... cannabis grow can be 2500. But in terms of per-canopy square feet, it may be a bit lower when you've normalized to the full gross square footage of the building. We're definitely seeing that horticultural lighting and high-performance HVAC systems used to keep these grows dry and at the right temperature causes a great amount of energy to be used. They can be more environmentally sustainable on the water side of things. We still need to normalize per harvest, because an outdoor grow might be only getting one harvest a year and using less water than an indoor grow, but the indoor grow is getting eight harvests a year. Just like the square footage, you need to normalize to the canopy, normalize to the harvest. That's what we're seeking to do with RII.

The last thing I'll say about greenhouses is that the jury's still out on if the location makes them more sustainable, because if you use a greenhouse with a dirty fossil fuel to heat it and a dirty electric grid to electrify it, you may be using more energy than an indoor grow due to the fossil fuel consumption. Indoor grows don't require as much heating. And then you're still using some horticultural lighting, which makes you worse off than outdoors. We need more data, here. RII has a benchmarking tool that allows folks to find out what their consumption is like. That's where I got those numbers from- cannabis folks benchmarking with our tool. We're doing that with USDA to benchmark leafy greens, vertical farms and others, too. Hopefully the baselines will start to emerge with the work we're doing along with the partners that we work with.

PR: It sounds like there is a good amount of energy being used and associated with a controlled environment agriculture. What are some of the things that your organization recommends in terms of best practices to keep some of that consumption of energy under control?

GS: Well I come from a building commissioning background as well as an energy efficiency program background and a couple of things I've learned from those sides of the industry can be well applied to indoor ag. The first of those is that when you're designing a new facility or retrofitting an old one, you should create owners project requirements to decide on your facility goals? Is it to maximize production while keeping operating expenses below some level? And in order to determine whether you can achieve that, find out the energy mix that these producers are going to use- are they going to be connected to the natural gas grid? What are the electric rates in their region? Are they planning on harvesting year round? Do they care about peak demand and how might they choose to minimize it? Knowing the utility actors in that space as well, the incentive programs that are available, technical assistance that can be provided. A lot of the utilities who are member of the group have free technical assistance they offer to producers to compare and contrast HVAC systems, lighting systems, and control systems. That’s what people need to be asking: “how can these environments be managed to keep energy costs and other resources impacts under control?” It's with automation and controls, and ultimately reporting to people who can impact business decisions.

Having a good building automation system that ultimately goes to some sort of data visualization is essential. This can be benchmarked to say "okay, we increased our operating costs, but we also increase production. That jives with our plan of getting this many grams per KB to you." That's what I think the smart and savvy businesses that stick around are going to have as a philosophy.

PR: We talked about energy consumption as it relates to lighting, but there's also energy consumption as it's relating to HVAC. More broadly about air quality and CEA, what is required? Are there certain humidity levels and is it like lighting where certain nanometers control production? Is there a humidity that's good for one type of educated vegetation but not another?

GS: HVAC is a complicated beast for indoor ag as well as greenhouses. Greenhouses are constantly impacted by the sun and by the outdoor environment. They have very dynamic conditions they have to deal with. They often are conditioned via ventilation, and the humidity can vary. Same thing with temperature. However, greenhouses often are conditioning using other methods like high pressure fogging, so they actually are doing things that are focused on humidity management, first and foremost. And that's how they control temperature. In indoor ag, they're often controlling with convenient conventional air conditioning. And so they're separately controlling humidity with dehumidifiers.

They sometimes ask for really aggressively low relative humidity set points. And so some of the energy saving opportunity actually comes from finding like what is the actual good humidity that you need to be at for flowering? Generally, the vegetative younger plants have higher relative humidity tolerances, because they're younger and they actually need some of that moisture. When you're getting into the older plants, they do not need as much moisture and you can end up getting powdery mildew and stuff a few if it gets too humid. The concern about air quality often comes into play with odor control for cannabis. We have an HVAC best practices guide for cannabis as well as an LED lighting one for cannabis, if you’d like to follow up in any of these questions.

PR: Wow, are those free resources?

GS: Those are free, and all of our best practices guides are free for education purposes. You can get them at

PR: That's great. We are an IoT integration company, and to me, it sounds like a goldmine of opportunity for automation. There just seems to be so many things that we could touch. And I imagine that you have put together a list of best practices for automation. Is that fair to say?

GS: We will cover HVAC, lighting, and water systems in the August best practices guide. Automating all of the lighting schedules is a great way to save energy, because you can also start to balance your flowering rooms. You can reduce your peak demand by having maybe half your flowering rooms on an off schedule, while the other ones are on. It may change your labor, but that's an automation strategy that's often been being done on the lighting side. Integrating HVAC and lighting systems to communicate with each other is another one that can reduce energy consumption by reducing the big spikes in humidity that happen when the lights go off. By dimming the lights slowly and by telling the HVAC that the lights are going to be turning off, you can actually prevent those dynamic big spikes. Many of our manufacturer members have shown that maintaining climate conditions within parameters consistently produces better product rather than having these variations.

PR: That's great! We’re excited about that, too. Thank you very much for a window into this business.

GS: Yeah, it's an emerging market and one to pay attention to. They're going to need a lot of the services that have already been demonstrated in other, more mature commercial and in this industrial markets. But there's the food side, the medicine side, and there's lots of different angles with greenhouse and indoor growing to be considered.

PR: Well, thank you very much. Is there anything you'd like to leave us with? Or did we cover everything?

GS: Get involved in organizations like RII so that you can start to specialize in this and get education on it. Stay tuned for more.

PR: We fully expect that this will be a growing segment of all the buildings built, and it's going to have to be designed by someone. I'm sure there's going to be architects and engineers involved at every part of the design process. And as an IoT automation company, we would also love to be a resource for you as project opportunities like this come up. We think that our automation and lighting technologies could accomplish a lot of the optimizations and best practices that the RII recommends. They will approach it from a technology agnostic approach as best practices typically are, and we will help apply those best practices to your design.


To learn more about controlled environment agriculture and how IoT integration can work beautifully with traditional farming techniques, check out this interview in its entirety on the latest episode of the Elevated Environments podcast.


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