A few weeks ago we told you about a better way to raise fish and grow food with recirculating farms. Recirculating farms are closed-loop, land-based systems that use constantly-cleaned water to raise fish and grow food.
There are three categories:
1. Hydroponic Systems
These systems grow plants in nutrient rich liquid, without what we traditionally think of as soil ("dirt"). Nutrients are added to water and plants may grow directly in the liquid, the liquid might periodically be sprayed on plants roots or it might flow by the roots as the liquid is recirculated in the system. Some farms use sand or gravel beds to support the plants as they grow.
2. Recirculating Fish Farms
These farms raise fish in tanks that have a water filter system to remove nutrients from the water for constant reuse, just like an aquarium at home.
3. Aquaponic Farms
These farms are a combination of aquaculture and hydroponics - where fish are raised in tanks and the water from the fish tanks circulates into the plant beds so the plants can absorb nutrients from the fish water. Then the water is returned from the plant beds, cleaner, and goes back to the fish for reuse.
The types of food that can be grown in these systems are expanding rapidly. Systems can be specifically designed to produce a variety of vegetables, herbs, fruit, flowers and more by using shallow or deep water grow beds, vertical towers and many other creative options. The wide range of plants makes the systems able to meet demands of local markets. In commercial systems, high-value plants with short growth cycles are often chosen to maximize profits.
But if there's no soil, what can you grow? Here's a breakdown.
In hydroponic farms you can grow much of the same produce, herbs and flowers that you can grow in a soil-based farm, including:
- Herbs like basil, cilantro and mint;
- Vegetables like bell peppers, cucumbers and tomatoes;
- Greens like romaine lettuce, rainbow chard and spinach;
- Flowers like cosmos, marigolds and zinnias; and
- Fruits like strawberries.
Recirculating Fish Farms
In recirculating fish farms, you can raise many types of fish and even crustaceans. The list of aquatic species is constantly growing and includes fish like tilapia, catfish, trout and prawns, as well as ornamental fish like koi and goldfish.
In aquaponic farms, you can grow produce and raise freshwater fish in the same system. Some of the most popular commercial fish include tilapia and catfish.
Recirculating farms offer us a chance to produce vegetables, fruits and/or fish that are clean, fresh, local and abundant - all of which adds to the sustainability and resilience of our local food systems. The next time you're wondering what fish to order, if there's a local choice, make it. There's even a chance it came from a recirculating farm.