Let there be dark: Square Roots on why it’s farming without light

By Oliver Morrison

- Last updated on GMT

Image: R&D project evaluating the effect of light treatments on the growth of basil plants. The team at Square Roots brings their knowledge of the grow platform together with the experiment goals of the company's partners.
Image: R&D project evaluating the effect of light treatments on the growth of basil plants. The team at Square Roots brings their knowledge of the grow platform together with the experiment goals of the company's partners.

Related tags CEA controlled environment agriculture hydroponics vertical farming crispr gene editing

US indoor farmer Square Roots is growing plants in the dark using gene edited (CRISPR) technology. The move could make indoor farming significantly more viable and sustainable, especially in low and middle-income countries, by reducing energy needs and costs that are typically driven by LED grow light, explains CEO Tobias Peggs.

Indoor farms’ ability to grow fresh, nutritious food, all year round, in any location, irrespective of outdoor climate, has obvious appeal. The farms use less water and land than conventional field farms. And if located close to the end-consumer, they support shorter supply chains, reducing food miles and reducing associated carbon emissions from transport, while being able to deliver same-day farm-fresh produce to customers, which lasts longer and reduces food waste. 

But to date the solution has been very energy intensive – primarily driven by lighting needs – which translates to high production costs.  

The industry is constantly trying to reduce costs by improving operational efficiencies or adopting automation, but while those gains are important, they are often incremental, according to Tobias Peggs, CEO of Square Roots. “The reality is that as an industry we must make step changes in reducing energy needs to significantly bring down costs – not to mention carbon emissions,” he said.

Could heterotrophic farming revolutionise the economics of indoor farming?

Heterotrophic farming is an innovative approach to indoor farming that eliminates the need for light to significantly cut energy consumption and costs. In this method, plants are genetically edited using CRISPR technology to grow heterotrophically. They absorb carbon from acetate (a vinegar-like substance) instead of relying on photosynthesis under LED lights. Innovators hope heterotrophic farming could revolutionise the economics of indoor farming, making it a more accessible and sustainable solution for securing the global food supply in the face of climate change.

The US company, co-founded in in 2016 by Peggs, a British AI expert and tech entrepreneur, and Kimbal Musk (yes, the younger brother of Elon) has already transitioned from being a commercial indoor grower selling its own produce, to providing an indoor farming platform, facilities, and services that other companies and partners can pay to use. It currently has five commercial-scale farms in the Midwest that are co-located on sites owned by Gordon Food Service, a major food distribution company that serves the foodservice industry across the US and Canada.

To further enable this new energy saving approach, Square Roots is working with gene edited (CRISPR) plants that add biomass by uptaking carbon through their root systems rather than relying on photosynthesis under light. Plants do this naturally at their early stages, and this gene edit simply maintains that natural capability for the plant’s full lifecycle. “We use acetate as the carbon source, which is a vinegar-like substance added to the irrigation water. It all adds up to plants growing ‘in the dark’ – or certainly with a lot less light, and therefore significantly less energy and cost.” 

Heterotrophic farming: can it be done at production-scale?

This fact is the big driver behind its programme to explore heterotrophic farming – where plants effectively ‘grow in the dark’, he explained. 

The programme aims to demonstrate that light can be removed from a commercial indoor vertical farming system. “All the benefits of indoor farming remain, but the system can now operate with radically reduced energy needs. This translates directly to significantly lower production costs and associated CO2e.” 

Tobias Peggs
‘Removing light removes the biggest energy hurdle for indoor farming, directly reducing costs and CO2e’ Square Roots CEO Tobias Peggs

The underlying science was initially developed by Dr. Robert Jinkerson, a specialist in artificial photosynthesis at the University of California (UC), Riverside, in conjunction with Dr. Feng Jiao, a chemist at the University of Delaware. They have been very successful with lab-scale trials in sustainable acetate production and heterotrophic plant growth. Now the Square Roots platform is being used to learn how to grow heterotrophically at production-scale.

“The ultimate aim of the programme is to develop a blueprint for low cost, low carbon indoor farms, specifically designed to maximise the benefits of this technique, which could unlock the full potential of vertical farming for new crops and communities around the world,” Peggs revealed.

Growing crops in the dark: the implications for global food security

This work is supported by a grant from the Bill and Melinda Gates Foundation. The foundation has invested significantly in programme to help ensure global food security, with a specific focus on low- and middle-income countries. “Traditional agriculture systems in these regions are likely to face outsized risk due to climate change and will also face big pressures due to population growth,” lamented Peggs. “The inherent climate-resilience and scalability of indoor farming means it should play a key role in the strategy to ensure global food security, but that will only happen only if its energy needs are reduced. So a breakthrough with heterotrophic farming would make indoor farming considerably more viable for these countries, where arguably the technology solution is most needed.”  

Multiple trials are already running, Peggs explained. “We’re growing leafy greens and tomatoes heterotrophically, allowing us to compare resource needs of this method vs indoor photosynthetic growth and also field farming. We started with Arabidopsis, which is a very bitter green, not really edible, but it’s often used as the model plant in scientific experiments as there is a significant body of research supporting its use. Its short growing time allows for faster cycles of research and analysis.” The learnings are then being applied to trials with longer growing, higher calorie crops.

Balancing ‘cool’ science with the real needs of a market

The second phase of the programme is running trials on lettuce. Since lettuce is the most commonly grown crop in indoor farms, the Square Roots team has good benchmark data to compare the energy resources utilised between photosynthetic growth and heterotrophic growth. “We can also compare that readily with field grown varieties. Lettuces also have relatively fast growth cycles, so we can rapidly iterate through multiple grow-recipes to capture yield data with different levels of acetate and light, including zero light. We will also be looking closely at crop quality to determine market suitability of the end product. The science here is obviously very cool, but we have to ensure that the technique results in a product that is delicious, nutritious, and that people want to eat. Obviously, there would be regulatory and adoption considerations to contemplate at that future stage as well – but that’s well beyond the horizon of this current research programme, as we’re really focused on fundamental plant science right now.” 

The third phase will be growing so-called SPACE tomatoes. This variety has already been edited to produce maximum fruit quickly in a very compact structure, Peggs said. “This plant is well suited to high density growing in vertical farms. Tomatoes will allow us to progress to understanding light levels necessary for fruiting and flowering in a heterotrophic system. Also tomatoes are an important global source of calories, representing 15% of total vegetable production.” 

The long-term objective is to tackle high-calorie, high-nutrient, staple foods. These don’t make economic sense in vertical farms today, Peggs believes, but could make sense with reduced energy costs. “From initial analysis we believe that potato and cassava can be readily adapted to efficiently grow indoors using this technique. Additionally, because our platform is modular, we can run trials with different plants, and even different grow systems, in the same facility at the same time. For example, we might have an aeroponic system for heterotopic potato trials while we run lettuce trails concurrently in a hydroponic system. As we extend our learning to other nutrient-dense crops, our platform can seamlessly adapt to accelerate that research.”

Could heterotrophic growing ultimately improve outdoor yields?

Given that agriculture continues to face pressures from climate change and limited resources – exacerbated, for example, by the rising average age of farmers globally – there’s huge scope for the heterotrophic farming, believes Peggs. “It’s exciting to think about the possibilities longer term. One can imagine a connected network of low cost, low carbon indoor farms across low- and middle-income countries, run by tech-savvy, data-driven farmers, producing staple crops year-round in sustainable and economically viable ways.”

The company doesn’t yet know what the optimal farm model will be. “Maybe these future indoor farms are not growing plants to full maturity, but perhaps they’re taking advantage of heterotrophic growing, plus perfect climates and high-density planting, to become super-nurseries that produce healthy and hardy starter plans to improve success rates of outdoor farmers and ultimately improve outdoor yields.”

Square Roots farm exterior
The Square Roots farm outside of Chicago is one of five commercial-scale farms the company owns throughout the Midwest co-located on Gordon Food Service distribution sites. Square Roots partners with companies like Gordon Food Service to launch new produce and to offer nutritious and local options with reduced food miles.

What’s important from Peggs’ perceptive is to avoid being pigeonholed. “I think in general indoor farming has positioned itself as a disruptor to agriculture – and perhaps boxed itself into a niche,” he explained. “We think indoor farming would do better helping to solve the big problems for agriculture instead of competing with it. That was a primary driver for setting up the Square Roots research platform – and this heterotrophic growing programme is a fantastic illustration of the power of that platform.”

Indoor farms can tap into health and wellbeing trends

Further illustrating Square Root’s forward-thinking ethos, it has also repositioned to focus on specialty customers, such as hospitals and health foods. “It’s definitely an important area for us,” Peggs said. “Healthcare is a $800 billion industry in the US, and the sector is undergoing a massive shift right now: ‘boomers’ are entering the system as patients and swelling its numbers dramatically; while their ‘millennial’ kids are now making decisions about healthcare programs for their parents, bringing strong preferences for things like healthy foods.”

Square Roots grow zone interior
Leafy greens growing inside a Square Roots grow zone in Grand Rapids, Michigan By designing each farm as a series of modular "grow zones", the company is able to trial multiple climates, genetics, and grow conditions in the same facility at the same time.

That combination is rapidly changing how this sector is thinking about food, he believes – from delivering "food as commodity" (cheap calories) to providing “food as medicine” (higher value, higher quality, with quantifiable functional benefits). “And as the research increasingly supports the value of this approach, these partnerships keep growing. Hospital Groups and Senior Living networks have been able to access our platform through GFS, and we’ve helped them develop a range of special greens, herbs, and microgreens packed with nutritional benefits like high levels of glycosylates to support cancer prevention, heart, and brain health. 

“It’s a great example of how the Square Roots indoor farming platform is being used to accelerate ag and food research for partners to help them meet their strategic goals.” 

How to survive and thrive the current market turmoil

There’s no doubt that the indoor farming sector has been through a challenging couple of years, says Tobias. But he believes that the robust companies being built, developing some very innovative technology, will ultimately make a very large and positive impact on global ag systems. “The best thing to do is ignore the noise, focus on the fundamentals of your business, consistently strive to deliver maximum value for your customer and partners, and make sure you’re doing everything you can to be one of those robust companies that survives and thrives.”

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