By Dr Jolly Kabirizi
Fish Farming
You can farm fish in natural ponds or large artificial containers such as plastic tanks. Tilapia, trout and catfish are the most commonly farmed fish in Uganda. If you’ve already got a pond on your property, then all you may need to do is stock it with fish and feed them. If growing fish in a pond, you need to take the source of water into account. A pond should ideally have an inflow and outflow equal to its total volume each month. If inflow is too low, the pond may not have high enough oxygen content and waste may accumulate in too high of concentrations. If water outflow is too high, then too much beneficial algae that fish eat may get washed out of the pond. Shallow ponds can work, but they should be at least half a meter deep to avoid predators and weeds. Fish food is available in a number of different styles including:
- You’ll need to get a specific type of food based on the type of fish you’re growing.
- In addition to growing full-sized fish, you can also operate a small-scale hatchery on your farm and sell fingerlings (juvenile fish) to other fish farmers.
Aquaponics
Aquaponics is a combination of a couple of different farming techniques: Hydroponics, which is growing plants without the use of soil, and aquaculture, which is growing fish or other aquatic animals. Aquaponics combines these two practices in a symbiotic way. Fish produce waste, which is converted into nitrites by bacteria that can be used to feed the plants.
Like most other farming styles, aquaponics can be adapted to all kinds of different levels of complexity and sizes. Modern aquaponic systems consist of:
- A rearing plastic tank where fish are kept.
- A settling basin where uneaten fish food is captured by filters and removed.
- A biofilter where bacteria that nitrifies the aquatic animal waste can live.
- A hydroponics system where plants are grown.
- A sump to pump water around the whole system.
Sell Fresh Fish
When you think of things that grow on a farm, fish probably isn’t one of the first things that comes to mind. The truth is that raising fresh fish can earn you a nice sum of money each year. If you’ve got a pond on your land that is really all you need to get started. You can start raising tilapia, catfish other varieties of fish. Fish also make a great addition to an aquaponic system. That’s where you combine hydroponics (growing plants in water) with animal waste to minimize the need for chemical fertilizers and other additives. The fish produce poop which provides nitrogen and other nutrients for the plants.
Hydroponics
Hydroponics is just aquaponics, but without the fish or other aquatic creatures! Instead, hydroponics relies on adding nutrients to the water to help plants grow. It’s a soilless growing method where plants only have their roots in contact with nutrient-rich water. Or they may be supported in a growing medium such as coconut coir or gravel. Most hydroponic operations use chemical fertilizers, although more organic options like goat manure are also available.
There are a number of different hydroponic systems to choose from.
- There are static solutions where plants are grown in containers like tubs or plastic buckets. Water may be unaerated or only gently aerated.
- Then there are continuous flow systems where the solution constantly flows past the roots, which allows the plants to better absorb oxygen.
- There’s aeroponics where a plant’s roots are only misted with nutrient solution and not actually submerged in liquid.
- Or ebb and flow systems where plants are flooded with water and then drained several times per day.
- Hydroponics are a good way to diversify your small scale farming operation and allow you to grow all year indoors or in a greenhouse. You can grow microgreens in hydroponics as well as full-sized crops.
