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A conversation with Jack Farmer the co-founder of LettUsGrow 

by Aimee Rigby/21-Feb-2020


Great. So, welcome to Zero Waste Kode. Would you like to introduce yourself?

Sure, yeah. So, I am Jack Farmer, I’m one of the co-founders of LettUs Grow, which is a start-up based in Bristol, UK, focusing on generating technologies for the vertical and greenhouse vertical farming and greenhouse markets. And we’ve been going for about five years now. And we’re about 30 people.


So, what does LettUs Grow do in a bit more detail? Where did the idea come from?

Sure. So, what we do currently, is that, so we have a leading product named Drop and Grow, which is a container farm.

For those that haven’t seen one of these before, effectively imagine a classic shipping container with a load of hydroponic- so, soil-free growing systems and LED lighting inside of it. And, that’s all packaged together so that people can grow food in the city, or near to a point of consumption. And particular innovations that we have as a company are actually in two areas.

The first is in the irrigation system. So normally, in soil-free growing you, you simply flow water over plant roots. Whereas what we’ve done is we’ve generated a slightly more innovative way of doing it, which is actually utilising a methodology called aeroponics, which is where you fire droplets, you fire aerosol at the plant roots. And because they can access better oxygen, you find that they grow a lot faster and a lot healthier.

And the other side of things that we do is effectively, we’ve made a software management control system for this indoor farm. And that effectively automates a lot of the workflows that you’d need to do to run a to run a small growing business. And so that’s our exciting first product, that’s how we’re entering the market, we’ve got some really exciting deployments over this year. And then from that position, we’re actually then evolving both of those technologies, so we can deploy them at really large scales. And we’re doing that with partners, we’re doing that with large growing operations around the UK. And some, hopefully, some have some exciting announcements to make over the course of this year about that. And so that I guess that’s what we’re doing now.

In terms of, and I can elaborate on that as required. But what we’re doing, where the idea came from, which will have been back in 2015, really, was effectively a desire to actually to really make a major difference within enterprise and in the food waste, and agricultural productivity sector. And I think Charlie, Ben and I all came at it from, from almost an impact first perspective, we were keen to utilise soilless agriculture to do so- it’s something that we’re very passionate about.

Myself, I’m from a biology background, Ben and Charlie, both engineering backgrounds. And, and so we looked for basically ways that we could innovate within that space. And I settled on our particular form of aeroponic technology as the way, the way to do that to hopefully boost productivity in these farms. And yeah, it all really derived from there over the years, we, we evolved that technology, we implemented it in a variety of different scales and, and have now are now in a position where we’re actually actively commercialising as a company. So, it’s been a bit of a journey, really.

Jack Farmer co-founder of LettUsGrow

So, you’re actually an Ellen MacArthur Foundation circular economy pioneer alumnus, quite a mouthful. Would you be able to tell us what a circular economy means to you and how it should work?

Yeah, sure. Well, this is something I’m very proud of. Yes, the Ellen MacArthur Foundation do fantastic work across the world, really working with companies to ensure that they integrate the circular economy principles into their business models.

Effectively what these are, it’s a framework by which businesses, organisations, can look to effectively ensure that they’re closing the loop so that they’re taking the waste products that they may have historically produced as part of their business models, they’re identifying how almost an order those can be reused, reimplemented or ethically disposed of, by recycling, so it’s about ensuring that the use the close the loop technology- it’s close the loop phraseology, sorry, because effectively, most business models historically have been very linear. So, you, you extract a resource from the environment, you use it to make a product, then you throw it away.

The whole concept of the circular economy is that by designing effectively from the start, you effectively design something that can be repaired, it can be reused, and it can circulate through the economy multiple, multiple times, until eventually when the materials wear out, they can either be reconditioned or, or disposed of in an ethical manner. And there’s two parts of that cycle.

There’s the biological side, which deals with food waste, or biogas, for example. And there’s the technological side, which deals with materials. So, this has quite profound impacts for I guess, people in my position in running a company, it really guides how we seek to design, and the benefit of that is that you really aim to design for simplicity, you design for repair, and design in such a way that things can be taken apart, reassembled and, and fixed. And it also impacts how we intend people to run our farms, so utilising wherever possible, consumables that biodegrade, which is obviously easy when it’s plants and seeds.

But when you’re looking at the consumables that you grow things on. It’s actually, in many cases, not typical that consumables within a greenhouse, for example, are biodegradable, the matting you grow on. So we aim to ensure that we’re always designing to, to support that kind of growing material. And so, I guess that’s just a bit of a case study in terms of our industry. But there’s many more in terms of other industries.


So, what are some of the sustainability issues faced by the agriculture? And how do vertical and greenhouse farming play a part to help address these?

Sure. So, there’s kind of two sides to this, I would split it into kind of controlled environment, horticulture, which is kind of your big glass house sector that produces the majority of for example, your tomatoes, your salad vegetables. And that’s certainly one side of it. The other side of it is field-based growing, that grows many of your cereal crops, obviously, the majority of your meat.

And but if I can just focus in on the horticulture side of it, I’d say firstly, this industry is growing very rapidly. It’s actually doing very well at the moment. And the primary issues facing it, I would say are primarily environmental, and from an economic standpoint, they’re pretty much- horticulture is pretty competitive. However, the model of the last maybe 20/30 years that was kind of the initial model for greenhouse horticulture, has effectively looked at centralised production in areas of beneficial environmental conditions.

So, if you look at the US, it’s California, if you look at the EU, it’s an area in the south of Spain and increasingly actually, Italy as well for many crops for like low tech and horticulture, met loads of polytunnels, for example. And, and then naturally, the Dutch have done a very impressive job in the last 30 years in, in centralising a lot of what’s called high tech horticulture and in that space. And there’s reasons obviously, the reasons for this are generally ones of beneficial climatic conditions, although the Dutch are doing a good job of kind of kind of getting around that. And I think, if I can use, I guess I’ll use California as an example, generally, your growing, it results in over intensification of farming in those areas. So, you get overly high levels of water abstraction, you get basically areas that are completely covered in plastic and glass, and you can see that from space. And actually, you get a lot of emissions from transportation. And so, you’re hauling or flying in the case of America, a lot of produce around from one place to another. And so, I think the first thing that the industry is starting to address is that by exporting this business model around the world, I would expect localised intensification in those areas of horticulture, but hopefully more of a broader spread of these horticultural institutions across the kind of EU and Americas, for example. And so that actually, you’re having lower impact on a regional basis, you’re lowering carbon emissions from transportation.

And you’re also and you’re also effectively more particularly lowering the water obstruction impact in these decertified regions. The second phase of innovation I would see is particularly in the… specifically would be in the growing systems that are used to run these facilities. And I think there’s huge areas for innovation in terms of, like I said, producing growing materials that are inherently biodegradable and ethical. And in also designing systems that are perhaps indoors, which is where the vertical farming comes into it, whereby you have a bit more control versus the outside environment. Or if you are in a glass house having an effective control system that allows you to adapt to the weather events that will reduce food waste losses.

Above images; Exterior image  of the Drop and Grow containers and interior design. The growing area inside a container and lastly, the  co-founders Charlie and Jack

One of the ways you aim to do this is using aeroponic technology. You mentioned a little bit at the beginning, but could you tell us you know what that is, and its benefits and how it works?

Sure, yeah. So effectively, the core principle to both of vertical farming, greenhouses, that you’re setting your plants in one position, generally, and you’re generally moving water containing nutrients to those plants. That’s the key principle.

The majority of these systems are soilless. So, whereas your plants may be anchored in a synthetic or biodegradable, growing medium, the actual nutrients and the irrigation are moved from the centralised tank round to the plants. And the challenge that you generally find in these systems and is firstly, if you’re indoors is firstly one of light and heat. So, you have to basically get some cheap enough LED’s, powerful enough LED’s, and take the heat away from them. That, fortunately, is being solved by the industry. And obviously in a greenhouse, it’s not really a problem. I mean, you’ve got ambient sunlight and, and the like, although there is work going on there as well. So, once you’ve achieved that, the fundamental limiting factor to these systems, is actually the plant roots ability to access oxygen. Because if you’re completely suspended them in water, the analogy I tend to draw is, is almost growing, growing food in a swamp. And not many crops can grow in a swamp because actually there’s not enough oxygen around the roots, they’re basically completely surrounded by water and effectively kind of drowned by that reality. And whereas what you generally want is the equivalent of a well aerated soil whereby there are air pockets from the source, the plant roots can breathe, acquire nutrients and, and grow to the maximum potential.

So, in looking to innovate in that irrigation system space, we have effectively gone down the aeroponic route, because you can still provide all the water and nutrients that your plants need. The roots have very low velocity and deposits on those roots. But they’re also surrounded by very humid air, it’s kind of a sealed cavity. But they’re growing in and they’re kind of suspended on matting, and they’re dropping down into this cavity, very humid, with aerosols being fired at them. And so, they’re getting all that water nutrients, but they’re also breathing and therefore, the plants are able to grow to their maximum potential.

And that’s one of the key productivity benefits of aeroponics. And that’s why we believe that as a system, it has real benefits to producing more food from these installations. There is a secondary benefit, which is that the nature of that system enables you to… this is getting bit niche. But the nature of that system actually means that you keep the medium that the plant is growing a little bit drier. And that means that it’s much easier to use a biodegradable medium. Because if you continually saturate those, they do break down and you will get an issue with pests and disease. So, I’d summarise it by saying the main benefits are those of productivity. So, growing things faster, to equivalent, high quality, and also pests and biodegradability, which has an ethical and operational benefit.


So, could you… you mentioned it a little bit again at the start. What is a Drop and Grow container farm? And who’s it for?

Yeah, sure. So, Drop and Grow is our branded container farm, it’s, I’d argue the world leading aeroponic container farm. Effectively these are targeted at individuals who are looking to start a growing business and aimed at people who want to disrupt the food system as it is and they want to supply direct to either food service, they want to supply direct to restaurant, retail, or perhaps public procurement contracts locally. And effectively- what you can do with a container farm is you have the benefit of buying or leasing one and deploying it in the most optimal location. So, for example, we’ve seen them deployed in container parks in the centre of cities, we’ve seen them deployed around the edges of cities and rurally if they have a benefit to existing growing businesses, for example, in propagation. And I guess the vision I would paint is that you could- you can initially get a single container with all the preparation and harvest space inside of it to start off, and then incrementally you can scale up that growing business much like the analogy we draw with regards to urbanites is really almost microbrewing- you’d see how the microbrewery revolution has taken off hugely in the last decade. And, you see these people who are passionate, competent, and inherently focused on their brand and their locality doing very well.

And that’s what we would see with the container farming space- is that it’s brand focused, ethically focused, zero food mile, business, can be started small, but then incrementally scaled up, because of course, you can add more containers next to your existing system. So, we see as a really exciting part of the market, it’s different to the large scale growing, where it’s all about price, and quality. Here, it’s all about quality, but it’s about ethics. It’s about brand, and it’s about having these systems embedded in the communities that they’re serving, and really building that relationship with the local food supply chain. So, I think that’s why we’re, we’re passionate about them. And for us, it’s a fantastic way to utilise and launch our technology. And like I’ve said, we will inherently keep supporting this business as this kind of product as a business, business leading product line. And then we’ll effectively evolve our technologies to provide and effectively supply and integrate into the larger scale vertical farms and greenhouses that exist, as well, because there’s some compelling technological innovations that we’ve made already that we’re very excited to deploy with some key partners over this year and increasingly across the world.


Fantastic. Yeah, that was that was really interesting. So finally, where can our listeners find out more about LettUs Grow?

Sure, so the best place to go is our website. So that’s And what you’ll find there is obviously a description as to who we are as a company, you find a description of Drop and Grow and the core technologies within that. And I’d really encourage you to engage there, to learn more about the food system, because even if this is not a business for you, it’s a very fascinating topic. The food system has a lot of change going on. And I see the change going on in controlled environment space has been really complimentary to the really exciting policy and, and agricultural innovations in the soil-based growing, field-based growing space, where we actually saw health and environmental benefits being really prioritised. So, I would encourage you to learn more about the food industry but also you check us out on our website.


Fantastic. Well, thank you so much for that information. And thank you for coming on the podcast.

No worries.


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