The AVF Workshop in Brussels was great. For the past few months, we have been working on-and-off on the white paper. We are starting to see the light at the end of the tunnel. Our white paper will look at the technical and economic feasibility of an urban farm in Brussels that processes food waste from its surroundings, upcycling it into high-quality food. This is to be done through aquaponics, mushrooms, and insects (AMI).

Of course, our white paper is theoretical. There’s a lot of work involved in implementing such a plan. Luckily, when I was in Singapore, I was introduced to a farm doing exactly that.

Citizen Farm is a farm in Queenstown, half an hour’s MRT ride from the CBD. Citizen Farm’s address is on Jalan Penjara. ‘Penjara’ is a Malay word for prison, which the main building on the site used to be. Inside this main building, we find aquaponics systems, leafy greens, microgreens, and mushrooms.

Like in our vision for Brussels, the farm aims to process food waste using black soldier flies (BSF) and mushrooms. BSF larvae can then feed an aquaponics system to produce high-quality fish and vegetables.

At the moment, these subsystems are separate. Citizen Farm’s partners are still tinkering with them. Once this is done, inputs and outputs can be connected to create a more circular system. This is challenging, because:

Singapore’s climate is completely different. The growers have to come up with new best practices through trial and error. Not all outputs can be 100% used. What to do with the residues? Especially in an urban setting. There’s a lot of interdependence, so the system has to be somewhat adaptable. Predicting the ratios between different production systems is somewhat tricky. Waste is always inconsistent in quality and quantity. It is also logistically difficult to get waste from foodcourts.

Less than a week after I landed in Singapore, Calvin Soh introduced me to Citizen Farm through Social Farms, which is unfortunately no longer at the site. The following weekend, I went to Citizen Farm’s open day with a few people from my university. From then on until December, I have been volunteering there (mainly for harvesting) on a regular basis and learning more about their different production systems. Most of them are quite small-scale. Let’s go through them:

Black soldier flies

This is where it all starts. Circento is the company in charge of black soldier flies. At the moment, there is a ‘tent’, if you like, full of racks of these creatures. There are plans to upscale operations to process hundreds of kilos of waste per day.

The main challenge lies in managing the odour, to avoid complaints from nearby residents. Circento has found a way around this. Keeping labour costs down is important, which is why the layout is crucial. The system is to be automated as much as possible. The next steps in designing the new building are climate requirements and making sure the operation meets regulatory standards.

Since there are too many black soldier flies to feed the aquaponics systems, Circento is looking into selling black soldier fly products directly. They are trying to find a way to process them in a way that would make them appetising. Black soldier flies leave a nutrient-rich residue behind, as well as some solid wastes. Circento is still figuring out how to use the solid waste, which there will be a lot of!

Aquaponics

Citizen Farm has two companies running aquaponics systems: iFarm and VertiVegies.

iFarm’s system is in the main prison building. They grow Jade Perch Fish. The plants used in the aquaponics system are leafy greens, including kale and spinach. These are grown in ZipGrow towers.

VertiVegies runs a container-based system near the entrance of the premises. There are leafy greens inside the container, as well as tomatoes and chickens, which are on a much smaller (experimental) scale. VertiVegies has designed these containers in-house and also does urban farming consulting.

Vertical hydroponics and microgreens

Inside the main prison building, we have Enfarm growing leafy greens. Sidd and Tim from Citizen Farm are growing microgreens.

Enfarm uses hydroponics, and is also experimenting with chilli peppers.

Citizen Farm grows all sorts of microgreens, which is a good source of income. These include red vein sorrel and pea tendrils. The microgreens are grown in soil and under artificial light. At the moment, spent soil is used on the outdoor crops.

Outdoor crops

Outside the main building, there are beds of coconut coir with all sorts of herbs and edible flowers. The coconut coir keeps the soil cool, protects it from weeds, and is a good source of organic material. Crops include blue pea flowers, snakeweed, and Mexican tarragon. Every Thursday I would go to the farm and help out with the harvesting. It was enjoyable.

There are also plants like ladies’ fingers (okra) growing in bags of soil under shading, as well as some soil-filled tower gardens.

Mushrooms

Last but not least, the mushrooms, done by Citizen Farm. Mushrooms have huge potential for processing. For example, spent sugar cane (used in sugar cane juice) is ideal. However, this is a challenge logistically. There are too many hawkers, each with very little. Lignocellulose from plants is another option in theory, provided there is no disease. Also, the strong compounds in tomatoes may not be suitable for mushrooms. Growing mushrooms is tough, so at the moment they are using coconut fibre to get an income and gain time to perfect the process.

There is still a lot of experimentation going on – medicinal mushrooms, using black soldier fly carcasses as a substrate, using different kinds of plastics (a problem encountered by Champignon de Bruxelles as well), and different kinds of pasteurisation techniques.

“Hello, would you like to try some kale?”

Citizen Farm has received help from Singapore’s Agri-Food and Veterinary Authority (AVA). It also makes money by selling its produce to individuals and restaurants, as well as by running various workshops. The farm sells its produce to individuals through Citizen Box, a box full of produce that can be picked up from the farm. Occasionally, produce it sold through the various farmers’ markets in Singapore.

I was fortunate enough to help out at three of these:

Of these three, only the last one was rural. We mainly sold leafy greens, microgreens, and edible flowers.

Our approach was to let people try samples. The blue pea flowers attracted people, especially children, some of whom didn’t believe they were edible! Kale was also popular. The kale you find in supermarkets is very tough and fibrous, but kale grown indoors isn’t – you can eat it raw. Ha, the number of times I’ve said that to people.

It was good fun to sell produce to the aunties and uncles of Singapore. One of the funnier remarks I got from one of the aunties was that I was too pale to be a farmer. I assured her that nowadays farmers can be pale, thanks to the technologies of indoor growing.

Closing remarks

The internet is a godsend. I am grateful to have been able to spend so much time at Citizen Farm. I met some fantastic people and gained an understanding of the practical side of implementing a project like the one we are looking at in Brussels, in the unique context of Singapore. Looking forward to seeing what happens over the months to come. Farmers of Citizen Farm, you are all wonderful people and I hope we meet again!

This article is part of a series on Singapore.

Click here to read part 1.

Click here to read part 2.

Click here to read part 3.