Experiments in Hydroponics

Climbing the steps to the roof at Maitreye through a maze of white tiles, one would not expect the lush, verdant explosion at the top. On my first visit in December, there was green everywhere: lettuce seedlings bursting from their small containers, melon plants cascading from horizontal pipes, even a small papaya proudly pushing the other plants out of the way. It was jaw-dropping, simply because on the sterile rooftop there was no soil, no earthworms, no visible ingredients to grow these plants except water, nutrient solutions, and some plant beds constructed with plywood, plastic sheets and styrofoam.

This scene is the outcome of Akash and Monica’s experiments in food growing, which they dub “Rooftop Hydroponics”. When asked why they’re doing it, they don’t wax philosophical about challenges of water or food systems in the world, both of which are under stress enough to warrant such experiments. “It’s fun,” they say, “and challenging”.

Their goal is realistic: to show that food can be produced in the tropics, on rooftops all over Auroville, in an affordable, low-maintenance way.

Rooftop hydroponics is by no means Akash and Monica’s first attempt at food growing. They have a long history of experimentation, most notably their work in Aquaponics, for which they received funding to set up a system that combined raising fish and cultivating plants in water. The system had several challenges, particularly the time and energy required to maintain it. When they wanted to move on, they looked for something simple and replicable.

That’s when they discovered the ‘Kratky Method’, a particular method of lettuce cultivation popularized by University of Hawaii professor Dr. Kratky. It begins by seeding the lettuce in small net pots in some kind of growing medium – coco peat in this case, as it’s easily available. The net pots float in a tray of nutrient-rich water, supported by a styrofoam sheet.In the absence of soil, the seedling’s roots grow downwards into the water, while their upper portion gets oxygen. Above the styrofoam, the plant flourishes, and a full head of lettuce is ready to harvest within 30 days – the same time required for lettuce to grow in soil.

Apart from daily checking of the water’s pH levels, little maintenance is needed while the plant grows. No weeding, no watering, no pruning. Water is not re-circulated through machines, so they are not vulnerable to electricity cuts. And although they have recently added oxygen to the water to give the plants a boost in summer, the Kratky Method doesn’t call for it.

Low maintenance is a key element in this experiment, as is little space (one rooftop) and low cost. All of the materials and nutrients were purchased within India and can be purchased locally or mailed to their doorstep. Setting up the initial infrastructure is the biggest cost. But the yield has the potential to pay back this cost, they say. They estimate that the cost of the nutrient solution works out to roughly Rs 5-6 Rs per head of lettuce, whereas they are have been able to sell it at FoodLink at the going rate of Rs 90/kg, but also at Rs 30/lettuce. It largely depends on demand. Hydroponics operations may feasibly be the only ones growing lettuce in the summer months, giving them an advantage on the selling market.

Although their Kratky experiment only began in November 2014, Akash and Monica have been able to sell some produce to individuals and FoodLink. The response from Aurovilians has been overwhelmingly positive and they’ve had feedback that their produce is delicious. People are generally supportive about the process, even the most strict organic food adherents. “Concerning the chemicals,” says Akash, “people are glad that we don’t use pesticides on the plants. Sometimes the nutrients contained in this solution are more than you would find in a barren field.” The micro-nutrients in the solution are required for healthy plant growth and include calcium, magnesium, sulfur, boron, cobalt, copper, iron, manganese. It is possible that heavily-fertilized fields, which have not been properly regenerated, could lack these trace elements.

For the present, Akash and Monica are focused on getting the system working well. They’re experimenting with Seaponics, or using seawater to grow plants, which already holds a lot of the necessary trace elements. They’re also experimenting with growing cherry tomatoes, Ladies Finger, basil, cucumber and melon. They have grown some of these on a homemade pipe construction, to which they have also attached a pump and a re-circulation system – demonstrating their commitment to constantly trying new things and to tweaking their systems.

Akash and Monica’s biggest challenge in the coming months will be coaxing the lettuce to continue growing through the heat of summer. My more recent rooftop visit in April’s heat revealed a less fertile scene. The plants had slumped over and were trying hard to survive in the heat, while others stood erect but lifeless. One could hear the silent burble of oxygen being fed to the water in the trays. Akash pulled up a plant and its roots – a key indicator in a plant’s health – looked baked. Instead of the fresh, robust white that they exhibited in December, these were stringy and coffee-brown. “It’s hard right now,” Akash said, referring to the difficulty of producing a delicate leafy green in summer temperatures, “they’re suffering”.

“But you should talk with Satchy, and see Alok’s place,” they said, talking about with two other Aurovilians experimenting in hydroponics in the summer heat. “They’re also scaling it up.”

On a visit to Alok’s hydroponic experiments being conducted at his workshop in Alankuppam, he and Satyavan show their work. The set up is similar to Akash and Monica’s but the key difference that sets it apart is its size: they are scaling it up.

“With India’s population growing by 16 million people per year,” says Alok, “resources like food, water, and space are becoming increasingly tight. We’re doing this to show that you can grow food in a small area using the least amount of water possible.”

Their infrastructure is on the ground because they don’t want to be limited to the size constraints of a rooftop in their goal of greater production. The system is newer than Monica and Akash’s and is enclosed within a massive shade-net construction. They use reverse osmosis, a water purification system that ensures there are no impurities in the water that might taint the experiments. “This is not necessary for home gardens,” Satchy says, “but important if you want to increase production”. The drainage water from the reverse osmosis is used to water bananas.

Alok dives into the numbers to demonstrate the benefits and simplicity of mass production: “140 heads of lettuce can fit into this water bed which holds 600 litres of water. If you do the math, that’s 4.2 litres of water per lettuce head. And in some places, they’re even getting it down to 2.8 litres! Compare this to traditional farming that takes anywhere from 13-28 litres of water to grow one head of lettuce. This method saves a lot of water.”

There’s also the money question. As with Akash and Monica’s set up, the biggest cost is the initial infrastructure. But once that’s paid, costs for growing are relatively minimal. From two bottles of Rs 600 nutrient solution, they estimate that they can grow 420 lettuce heads – about Rs 2.86 per head. There is, of course, the cost of seeds, water and electricity, depending upon where you live. The cost of reusable net pots is negligible, as are labour costs because the system hardly needs any maintenance.

The aim is to choose a food product that they can produce consistently, year round, for the Auroville and Pondy markets. Lettuce is the easiest choice, as it is one of the simplest crops to grow and the lightest plant for the styrofoam to carry. “We might also try other dark leafy greens, which have been grown successfully in Malaysia and Taiwan,” says Satchy, who has also been experimenting at his home in Certitude with hydroponics and is often referred to by the others as the “mastermind”.

There have been a few challenges so far. With operations on the ground, they’ve had to deal with a mischievous rat that scratched its way inside and destroyed some plants. Leaking plastic tarps are another issue. They’re concerned about the monsoon season, when heavy rains will dilute the nutrient-content in the water trays.

But they remain convinced that the method can work on this larger scale and in Auroville’s climatic conditions. Alok’s visit to various large-scale hydroponic operations in Spain in 2013 was a source of inspiration. Both have pored over studies on the nutritional quality of hydroponic leafy greens, which in some studies has shown a higher nutritional content than lettuce grown through traditional methods. They’ve researched how to reduce the food miles footprint even more, and how to source their supplies locally. They talk about how a healthy relationship with their suppliers is critical to the long-term sustainability of the project.

Their motivations for the work vary slightly. While Satchy’s motivation is to ensure that more of Auroville’s food is grown in Auroville, Alok is interested in growing food most efficiently. “We’re not competing with farmers,” said Alok. “We’re just trying to show that you can produce food in this way. This experiment isn’t just for Auroville, it’s the kind of stuff that Auroville needs to be offering to the world.”

As for how people might react to their work, they’re expecting questions around the concept of ‘organic.’ “We need to rethink the original definition of ‘organic’ which is based on food only grown in soil,” Alok says. “We will offer a product that hasn’t been treated with any pesticides, that uses much less water than conventional lettuce, and has low food miles.”

Both Alok and Satchy stress that it’s too early for any real conclusions and to check back in a few months, particularly after the summer heat. Their first step is to grow, and then see if they can further enhance the yield by using different types of water. Alok is conducting other water experiments on the site, creating a symbiotic laboratory for the two projects.

In a system based on efficiency, is there anything lost in hydroponics? “There’s nothing lost in quality,” says Alok, “Some people have a sense that you are tinkering with nature when you are not growing lettuce in the usual environment of soil, but the benefits of the controlled environment of hydroponics and minimized water usage cannot be denied. There is a faster growth rate and higher yield in hydroponics. There is no need for the constant watering, weeding, and maintenance of the crops as one might have on a farm, all of which are elements of traditional farming. But given how the population of India is growing, we no longer have that time to spare.”

For more information, please visit Akash and Monica’s blog:

 rooftophydroponics.blogspot.com