A restaurant with an in-house farm: How Prague's Štangl is embracing hydroponics
A tasting dinner at Štangl
Dmitrij, how did you come up with the idea to produce hydroponic farms?
You'd probably expect me to have some kind of agricultural background, but it's just the opposite. I run a machine shop in Hradec Králové and I primarily deal with projects in industrial automation. Ironically, the topic of hydroponics came to me in China, where I stayed in 2019 – living in a Chinese apartment in the middle of the city made me think about how an individual can improve the environment. And since I'm into technological containers, I started thinking about what I could fill them with that would make sense both environmentally and economically.
I studied various sustainable technologies and in doing so came across hydroponic systems, which seemed to be the least challenging. I was wrong. I soon realised that it was a separate scientific discipline. So when I returned to the Czech Republic, I formed a working team of a few people who, fortunately, quickly identified with my vision of vertical container farming. Initially we didn't think about the commercial side of things – the farm was only to serve the employees of our original company, but eventually we went all in.
What did it entail?
First, we set up a small lab so that we could investigate the technological, agricultural and cultivation processes. We decided to build a fully automated farm with our own software. In a relatively short period of time, we launched two pilot models. The first was the GreeenBox, which is essentially a shipping container adapted for cultivation. It's located in Manifesto in Prague's Anděl district, and was recently bought by the online supermarket Rohlík, so they are now growing some of the crops themselves. In the Štangl restaurant, we installed a second variant called Urbanio – a modular indoor farm.
Our clients include mainly shops and supermarkets, but we also target businesses or catering. Reaching restaurateurs in the Czech Republic, however, is much harder than abroad – Štangl represents only our third installation on the Czech gastro scene. We found that we had to approach it in an educational way. Businesses often don't understand why they should invest in something like this.
GreeenTech
GreeenTech has been developing since 2020, when Dmitrij Lipovskij returned to the Czech Republic from China – with an idea for a hydroponic farm housed in a container. He soon managed to get a team of people excited and turn his vision into reality. The originally non-commercial idea turned out to be a start-up that stands on three pillars – environment, experience, education – and invests in education across generations.
What are you trying to convince them of?
Here are a few reasons. First, we mention hyperlocality and the farm to plate principle. It's not about the chefs growing all their own vegetables, but at the very least, it's about ensuring fresh herbs and salads – it shortens the journey of the ingredients to the kitchen and they can keep an eye on their quality. Another advantage is diversification – you can grow around twelve different types of produce in one container. Plus, it's a design thing that beautifies the restaurant space.
How does such a farm work?
Our system is based on hydroponics, but it falls into a subcategory of hydroponics that is described as "vertical farming". While hydroponic farming used to be considered part of agriculture, it is now evolving into a separate segment. Vertical farming is still a young and unexplored field, and there are many aspects to contend with – the fact that we are bringing technology and living plants together is a challenge in itself.
Hydroponics is about growing crops in a closed, controlled environment, without soil or external influences such as pests or polluted groundwater. This allows the grower to avoid pesticides and chemical fertilisers. But let's be under no illusions – hydroponic greenhouses with huge yields often over-fertilise. Furthermore, they are often prove to be an economic failure due to the high cost of heating and lighting. This is also why we have opted for a small size that allows us to produce "cleanly" and sensibly.
What makes your farms different from greenhouses?
First of all, they are not as energy-intensive – they use ambient heat, they are not cooled and they are only lit for 16 hours a day. A Hungarian company has developed lights for us that offer five colours and four light spectrums. These are controllable, so they can be tailored to the plant and it grows in the most natural light conditions. This also helps to regulate energy.
The strongest argument for hydroponics, however, is the water it saves – proven to be up to 95%. For example in Urbania at Štangl, consumption is around ten litres per day, which is equivalent to one flush of a toilet. Not to mention that the container takes up 20 m² of growing space, which would be about 2000 m² in a field. And that is no small amount, especially at a time when healthy fertile soil is rapidly diminishing.
How exactly does the container work with water?
Each system requires water treatment in a tank where various sensors are placed. Once the computer has analysed the water, we determine how it will be fertilised. We use two organic fertilisers to raise or lower the pH and EC (electrical conductivity). Then we let the water circulate – the plants are watered, nourished and the remaining liquid is returned to the tank. There, the proportions are cancelled and readjusted with the correct fertiliser dose.
We are constantly trying to optimise the fertilisation in cooperation with the Academy of Sciences, where we regularly send water samples for testing. Based on this, we then reduce the amount of fertiliser so that the plants thrive and at the same time do not pollute the technology as much with salt deposits and other substances. The aim is that we don't have to sanitise the containers every quarter, but perhaps only once every eight months.
What does looking after the farm ask of the cooks?
It depends on what type of service they choose. They can either take care of the farm themselves or leave the servicing to us. At Štangl, we've settled on the second option, so we'll bring them seedlings or crops that are two to three weeks old to start, and then we'll stop by the restaurant once a week, to check that everything is running as it should. However, we manage the farm from our head office and can do a technical check or minor repair remotely. The actual harvesting is handled by the on-site team.
What kind of harvest are we talking about here?
In Karlín, they have ordered the smallest model, two modules with three floors, in which around 400 crops are harvested per month. The number varies, of course, depending on the composition of the plants – for example, lettuces fill a larger area than herbs. But in the kitchen, they can determine how often they want to harvest a given crop. We can adapt to this too. On the other hand, we have our own conditions from which we do not back down.
We accommodate the chefs, but in the end we only supply them with crops that thrive on our farm. If they order something we haven't tried yet, we start researching – in two to six months we can find the seeds and see what kind of environment they will grow well in. We're currently researching about 20 new crops. We don't want our containers to just be used as a showcase, and with your purchase we guarantee production that is economically worthwhile. As a rule, we don't even recommend fruiting plants like tomatoes or strawberries – a few kilos would cost you too much energy unnecessarily.
Where do you get your seedlings from?
We grow them ourselves in Modřany, in our vertical farm. It's another service for customers who don't want to look after vegetables from seed, but are looking for good raw ingredients. Together with the farm, we will deliver seedlings of organic quality, although it's not yet certified – hydroponic production does not have its own legislative directive. In any case, the nutritional value of our crops begins where the quality in conventional farming ends.
Is it really possible to grow healthy produce that's full of flavour and aroma without soil?
You're not the only one who doubts it. Many people believe that a plant can only be wholesome if it is provided with soil and sunlight. Not every crop is suited to hydroponics – it's quite a challenge with spinach, but the vegetables from our farm in particular have a great taste, smell and appearance. Nutritionally, we consult with the aforementioned Academy of Sciences, which helps us oversee quality and comply with hygiene rules and guidelines.
As I said, vertical farming is still in its infancy and we have room for improvement. We are currently switching to a new substrate. Traditional hydroponics uses special glass wool, we are introducing peat. It's more expensive and more complicated to maintain, but it meets the ecological requirements, can be disposed of in bio-waste, and what's more, some plants grow better and faster in it.
Is this, in your opinion, the scenario of the future that will be on our plates?
I dare not say. But hydroponics is becoming our livelihood. For now, we can still grow lettuce in the field, but if we don't consider our behaviour towards nature, there will be a problem – the land will be built up or degraded to the point where it stops producing. Already there is talk of a major decline in biodiversity. In short, we have reached a situation that is alarming and will hopefully push us towards sustainability.
What does sustainability mean to you?
I think it is a word that has been overused and perhaps that is why it has not had a clear meaning in recent years. I think it would be quite enough if we took stock of how we live our daily lives and took full responsibility for them. As a father of two, I feel this more intensely today than I used to.
GreeenTech never claimed to change the world. We want to build farms that feed the immediate neighbourhood, whether that's a restaurant or an office. In doing so, we're not interested in acres, but in communities of people who care about what they eat and how it affects everything else.
