February 2026

When I was young I had an aunt living in Kent who had a little greenhouse in her garden. She grew the most wonderful tomatoes and cucumbers in it. Green houses have long been popular with the gardeners of Britain, to keep the sharp east wind off their plants. Sometimes they had a little paraffin heater in them against frost, but for light and water they just relied on the sun and an outdoor tap. Half a century later, we've come a long way. It looks as if all the salad in Britain may soon be grown hydroponically in a form of super-greenhouse. Techno-lettuces, you might say?

During WWII the UK government had to cope with the problem of feeding a population of nearly 50 million people. Britain had depended for a long time on exchanging manufactured goods for food grown in other countries and there was no way that it could supply all its own food for that number of people. Every schoolchild knows about the heroic solution. It worked, but we may be facing a similar situation again soon. We still rely on imported food, and if our supply of imported food were to be interrupted for some reason, it would be far more difficult today. The UK population is now nearly 70 million and there just isn’t enough spare land. An enormous amount of what used to be farmland is now covered by a creeping sprawl of homes, offices, factories, roads etc. If our supply networks were interrupted we would have a serious problem. And these things can happen very quickly.

The favoured solution at present appears to be vertical farming, a form of indoor farming. Vertical farming means growing vegetables in giant greenhouses, not only outdoors on land usually farmed by traditional methods, but in places such as disused mines and tunnels, underground car parks, shipping containers, or on the roofs of buildings. The plants are grown stacked on shelves one above the other, or in towers, so that there is a massive crop from a very small footprint. Orkney is an agricultural area with centuries of experience in growing plants adapted to a difficult climate. Even here, the local college is working on a vertical farm project to avoid the difficulties of importing fresh fruit and veg to a remote storm-lashed island with a short growing season and hardly any daylight for several months per year.

Instead of using sunlight, the vegetables use artificial light from LED lamps. They are usually grown using hydroponic or aeroponic techniques rather than soil. The plants may have their roots in an inert substance such as perlite, with a water-based solution carrying all the nutrients they need running through it (hydroponics). Alternatively, they may have their roots growing down into a container where they grow unsupported but are periodically sprayed with a fine mist of water carrying the nutrients (aeroponics). There is even a method called aquaponics, where growing vegetables hydroponically is combined with farming fish. The waste water from the fish tanks is passed to the vegetables, providing them with nutrients, and then, having been purified by the plants, passed back to the fish.

These methods give complete control over light, temperature, humidity, and water, the vital things needed for plants to grow. Pollination of flowers such as courgettes or aubergines is done artificially as well. (What is the future for the pollinating insects I wonder?) This is known as Controlled Environment Agriculture (CEA). The use of LEDS means that you can supply the exact spectrum of light which a particular plant needs at a particular stage of its growth. These greenhouses use less water than a conventional farm, up to 95% less, because it can be recycled. They create less pollution than conventional farms because everything is done by electricity rather than tractors belching diesel fumes, although that of course depends on how the electricity is produced. There is far less need for pesticides and you don’t have to weed them. (Or worry about slugs.) The technology can constantly monitor how the systems are functioning, for example the pH of the nutrient fluid, the temperature and humidity of the surrounding atmosphere, and how well the plants are growing. Labour costs are kept to a minimum, because much of the process can be automated and controlled by computers (you may not consider that an advantage, if you are having trouble finding a job).  They are independent of the weather outside – gales, droughts, unseasonal snowstorms are no problem.  And you can grow food in cities so that it is close to consumers and food miles are low.

 In other words, you can grow large amounts of vegetables all year round, unaffected by bad weather, in a very small footprint, close to consumers and with fewer sources of environmental pollution, in a sophisticated form of greenhouse.  Sounds perfect.

Well, not quite. Some varieties of crops are more suitable for these techniques than others. Leafy greens such as lettuce, kale and spinach are easy, so are things like strawberries, tomatoes, peppers and cucumbers. But you can’t live on lettuce, and root vegetables are more difficult. However, it looks as if it might be possible to grow some of the staple carbohydrate crops this way.  Apparently potatoes are a possibility, although at present this is not considered commercially viable in the UK. Japan is experimenting successfully with growing rice hydroponically in vertical farms in disused warehouses. Rice is also being trialled in India. Barley is currently being grown hydroponically, although the articles I have seen focus on growing fodder for animals rather than humans. It can be grown very quickly using minimal amounts of water. I read about a fascinating project developed by refugees in the desert in western Algeria, with help from the World Food Program and Oxfam. These people are victims of desertification due to climate change. Unfortunately, climate change causes some people’s farmland to flood, in other places it becomes desert. They have been growing barley shoots hydroponically as fodder for their traditional sheep and goats.

There are some commonly-acknowledged drawbacks. These systems are expensive to set up, since they require a lot of specialised equipment,  for example LED grow-lights, or pumps for the nutrient fluids. You need ventilation and constant monitoring of the atmosphere to make sure that moulds won’t grow and there is enough CO2 for plant growth, which means electronic sensors and computers to analyse the results and make the adjustments. All this complicated equipment needs constant maintenance. It requires quite a lot of technical expertise in a variety of fields to set up and run an indoor farm successfully. And as it is a new technology, it is constantly changing and farmers or farming business have to keep on upgrading. Anybody who gets frustrated by the constant upgrades on their laptop will know all about this problem.

Doubts have been cast on how commercially viable they can be because of the large amount of electricity required. Renewable sources such as solar power are used, but power outages can be disastrous – a whole crop can be lost in minutes. Usually a back-up source is installed. The same goes for water. Even if the farm uses a system where water can be recycled it is usually necessary to top it up from time to time. There seems to be some confusion about plant pests. Although they are said to need far fewer pesticides, I have also read that waterborne diseases can spread very quickly, and tiny pests like aphids and thrips came become a problem.

Above all, there are possible supply chain problems for the technology. For example, there are firms based in the UK which make grow-lights. But when you search for what materials are needed to manufacture grow-lights, it would take several pages to describe them. And among them are rare earth minerals, 98% of which currently come from China. Other sources are being developed or “acquired”. But it seems to me that vertical farming merely moves the danger from supply chain problems one stage further on, from problems importing lettuces to problems importing the equipment to grow lettuces. A contribution from high-tech farming may be necessary to feed a massively oversized population, but we should remember that it isn’t in any sense a panacea.

And when I look out over the fields in Orkney and watch the wind creating moiré patterns across the fields of golden-brown barley, or watch a farmer ploughing a field with a flock of seagulls swooping and diving behind his tractor as it turns the earth, or even, when I smell the slurry that wafts throughout Orkney when the farmers spray the muck from their cowsheds onto the fields, I can only hope that conventional farming won’t disappear completely. Somehow I feel safer buying my food from a farmer who has at least some personal contact with the land and the seasons, rather than a businessman who considers raising crops a matter of computers, nutrient fluids and LEDs.