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Adjusting our Floating Raft Aquaponics System

When I first arrived to Taino farm the first thing I noticed about the aquaponics system was the amount of tomatoes. I had never seen tomatoes grown in a Floating Raft system and the ones growing did not look healthy, I soon realized why. Tomatoes and other fruiting plants such as cucumbers and peppers can do very well in Aquaponic systems but not in Floating Raft Systems. This is due to two reasons: root structure and nutrients available.

Floating Raft Aquaponics is the growing of plants directly in water without any media. The roots receive no support in the water that they normally have growing in the soil or another solid growing medium. Consequently, our plants relied heavily on being tied up with string that moved constantly with the wind and caused unhealthy growth. The second reason fruiting plants do not grow well in Floating Raft Aquaponics is the lack the essential macronutrients such as phosphorous and calcium. These are necessary for a plant to successfully achieve reproductive growth, producing flowers and eventually large fleshy seeds that promote new life. However, in floating raft systems these nutrients are not present because the fish solids are filtered out before the plants have access to them. The solids need to be filtered out because otherwise they would clog up the piping and fill the plant beds with dirty water that can cause root rot- a fungal infestation on the plant root that inhibits oxygen intake by the roots (which is another problem we are currently dealing with in our system).

When the solids are removed the only nutrient that is widely present in the water is dissolved ammonia produced by the gills of the fish. This ammonia is converted to Nitrite then Nitrate by the bacteria in our biofilter before it enters the plant beds. Nitrogen, in the form of Nitrate, is the promoter of healthy vegetative growth such as the stem and leaf matter of a plant. Therefore, growing plants that are harvested before they begin reproductive growth is essential for a Floating Raft Aquaponics system. Some of these leafy green plants that we are now growing instead of fruiting plants are multiple varieties of lettuce, kale and arugula, and many herbs and spices such as basil, cilantro, oregano, chives, hibiscus and mint. These kinds of plants are perfect for Floating Raft systems because they are smaller and don’t require a large root support system as well as only relying on the Nitrogen in the system and are harvested before they go to seed.

What one of our Aquaponic Floating Raft plant beds look like now:
What one of our Aquaponic Floating Raft plant beds look like now

On the other hand, we have planted many fruiting plants such as tomatoes, eggplant and peppers in our Media Beds and they are growing well. This is because there the plants grow in rocks that form support for the roots. Furthermore, we grow worms inside the rock beds that consume the solid fish waste releasing the essential nutrients that a plant needs for reproductive growth producing flowers and seeds.  

gravel media bed
What our Aquaponic Media Beds look like now

Introduction to Aquaponics

Introduction to Aquaponics

grow beds
Gravel aquapoincs

Aquaponics is the re-creation of a natural ecosystem with the focus of manipulating the Nitrogen cycle to work for your growing needs. It is the combination of Aquaculture (the growing of fish) and Hydroponics (the growing of plants in a soil-less media). The three most important organisms in an aquaponic system are the fish, nitrifying bacteria and the plants. Fish produce Nitrogen in the form of Ammonia both from breathing through their gills and through their waste. When in a closed tank system, if the Ammonia level becomes too high it can cause harm and death to the fish. As the waste filled water is removed from the fish tank it must be accessed by two kinds of nitrifying bacteria in order to convert the Ammonia into Nitrite then into Nitrate. Nitrate is the form of Nitrogen is readily accessible to plants and plays an important role in healthy growth. The bacteria in system must have a large enough surface to live on where the dirty fish water can pass through in order for all of the Ammonia to be changed into Nitrate. The Nitrate filled water then must make contact with the plant roots in the system so that the plant can uptake the Nitrogen and use it for growth. After the water has passed through the plant roots it should be completely free of all forms of Nitrogen and therefore is clean and may be recycled back into the fish tank. In an efficiently running aquaponic system up to 90% less water is used than conventional growing systems.

There are two types of aquaponic growing systems here at Tiano Farm, Media Beds and Floating Rafts. Our Media Beds are made from an IBC tank cut in half, one being filled with water and fish and the other with rock media, bacteria worms and plants. Plants grow directly into the rock media that is constantly flooded and drained with water from the fish. The worms live in the rocks and break down the solid fish waste into a form of nutrients the plants can use. The bacteria also live on the rocks and change the Ammonia to Nitrates for the plants. The plants then clean the water of nutrients and it is recycled back into the fish tanks.

 

Here are pictures of one of our Media Bed Systems:

Aquapoinc Tilapia
Tilapia living in our aquapoinc system

The Floating Raft system is a different form of growing where the plant roots are grown directly into the fish fertilized water. The plants are placed in Styrofoam that float on top of the water and the roots hang into the water to clean it for the fish. In this type of growing system because there are no rocks present, the solids must be removed from the system because there are no worms to break them down. Also, there is no surface area for the bacteria to be grown on so there must be another home for them called a bio filter present. We use plastic balls and mesh for them to live on in our system. The solid and bio filters must be separate from the fish tanks and plant beds.  The ammonia filled water leaving the fish tank must first go through the solids filter, then the bio filter, into the plant beds for the plants to use the nutrients and clean the water to be recycled back into the fish.

 

Here is a picture of one of our floating raft beds:

Float rafts
Float raft Aquapoincs

Update February – Moringa

The farm uses a ton of moringa.

Moringa is an incredible plant, and has various nicknames. It grows like a weed and has a ton of uses, and is a fantastic source of vegetable protien. We use it for various uses, from feeing the fish in our aquapoincs system, feeding our happy chickens, to feeding cattle.

The chicken ‘corrales’ are lined with moringa so we can chop and drop right into the chicken runs and they immediatly eat it up. We then take the stalks and plant them on the property, as we manage to use up the moringa.

Going forward however, we are about tot have a ton of moringa. Initially we just built some basic netted shelves, and let the moringa sun dry. It’s been working, and most importantly we need to to grow the farm to the next level.

The next growth we want to put moringa drying area underneath the apartment, into what is about to become the production area. We are going to start to produce finished products at the farm, as selling organic heirloom peppers for 50 RD a pound will not make the farm sustainable. We need to produce an incredible sustainable farm hot sauce with a mic of the various home grown ingredients that we grow at the farm. The farm needs to have a bunch of products that are produced on a rotating basis. Monringa powder is one of those products.

Victor, who is the one who handles most of the day to day of the moringa drying with Brandon, suggested that we use the old cement structure that held the first solar panels.

The first solar panels at the farm are a story unto itself, but we’ll get to that one another day.

To build a solar dehydrator using the existing cement structure. The easy way to achieve that is get a plastic transparent roof and extend the roof. Level out the ground and move the current moringa drying rack s to under the tarp. The harder but not too hard next step is using the cement structure to build drying racks, build heating ramps – similar to Anton’s version, but fixed. have multiple heating ramps

Finish off the intern buildling first floor – which means paying the ebanista to build in the screens

Finish off the first stage of the productioon room, and get production going

this we can make now

hot perpper sauce
mint sauce
pesto
moringa powder – start of our protein poweder
tomato sauce
kambucha
coconut water for the gym

for not much investment we could add in

coconut oil
moringa oil
almond butter
essential oils including citronella, lemon-grass, moringa, coconut, ton of the items on our lit

All these items will give us products that can be made weekly and stored in small president bottles that can then be sold for 10 x the cost of what we can sell the produce for

Talked to victor about replacing ocar. the guy who cooks the pig it a good worker, and victor wants him on the same hours and same salary – 7000/moth – and he’ll focus on all the gardening – cleaning up the fruit trees, clenaing up the whole property. it would be good to get him working with Robb – that should help a lot

the barbados cherry is flowrin

the jackfruit is flowring a lot

victor is building out the wall on the 4th chicken corrale – planting moringa and put up the fence. on top of that, they are starting to weed and plant out grass into the various corales. the moringa is growing in well along the fences.

we talked about chicken production – the chicken nursery/hatchery. victor figures he has about 4-6 eggs/day, and these are fertilized eggs. the idea is that after they lay, victor moves them into the sheep building with the mom who sits on them there – when the hatch, he lets them run free until they are ready to either be layers – or meat birds depending on the chicken’s sex. low food needs, and they are busy cleaning put eh property and running around. could potentially section off all the areas that are bein cleaned now, in the various orchards – an keep meet chickens in there to keep the area clean – low numbers so they eat largely the weeds until we can plant out grass and get all the areas under control

Introducing farm intern Brendan

Hello All! My name is Brendan Cormier and I have been working at Taino Farm for 2 months now and have fallen in love with the farm here and have no intention of leaving any time soon. So I have started this blog to inform interested people about growing Tilapia in an aquaponics in the tropics of the Dominican Republic.

A little background about me: I graduated last year from the University of New Hampshire with a Bachelor of Science in Sustainable Agriculture and Food Systems with an emphasis on agricultural business management. During my time at UNH I studied abroad in Costa Rica and found my calling to live in the tropics. I had visited my adviser and professor Andrew Ogden’s farm and when I returned home I asked him if he had any projects that I could get involved with to keep me in touch with Costa Rica. It was then he introduced me to aquaponics! I then spent my final two years of school studying every aspect of aquaponics and designing a commercial sized system to install at Andrew’s farm.

aquapoincs internships
Brendon loving it!

However, when graduated from UNH I realized hands-on experience working with a large-scale aquaponics system was necessary to study and learn how to manage a system myself. With a simple Google search of: Aquaponics Internship I have found myself back in the tropics in Dominican Republic learning more than I ever could have imagined. Taino Farm is a 10-acre farm in the rural town of Los Brasos about half an hour from Cabarete; the popular kite surfing beach town where the owner of the farm Robbie also owns Extreme Hotel, where most of the produce from the farm is sold.

I have been working on many different projects here involving the aquaponics systems at the farm and hope to help grow the system for the better. My projects as of now include: Finding the correct plants to grow, studying the water parameters of the system as a whole to make the system healthier and function more efficiently, and designing my own nutritious locally produced food source for the Tilapia in the system.

Daily Update: Tilapia breeding and feed

Tilapia Fish waste solids from the filtration system

What is happening to the Tilapia waste solids from the water filtration system in the commercial production aquapoincs system?

The solids are being used to fertilize the nearby tropical fruit trees.

Previously the Tilapia fish waste solids were meant to be going into the duckweed grow bed system, which provides part of the feed for the Tilapia .

The duckweed system is not at full production yet, and we figured it is in lack of nutrients, so we have been adding Chicken waste as a nitrogen source, and Duckweed likes the ammonia.

Solution: We need to talk to the team to figure out why where they have to be going.

Tilapia breeding room

What is the correct temperature for the Tilapia breeding system or the hatchery?

The water for a Tilapia breeding system should be at 25 C for ideal mating conditions. Right now we are at 22 C and the fish are not mating, there are no eggs, and there does not seem to be any mating circles. Previously we figured the temperature was too high as we were up to 29 or 30 C at some times during the summer months. Juan seems to remember that the fish were reproducing at 28 or 27. That might be the upper range for heat. We bought an aquarium chiller for the summer when the temp goes that high.

Perhaps we should start tracking the fish – how many mating sets are pregnant, name each mating set, organize it to get more efficiency of out of the hatchery.

Solution – We are planning on connecting one of the grow beds from the nursery to the Tilapia breeding take system. It should have the additional benefit of helping to clean the water. We were thinking that the nitrates were too high previously with Nico.

We are not too concerned with cross contamination because the systems are already shared – one way is from the fry Tilapia leaving the breeding room when they become fingerlings.

Black soldier fly larvae harvest

Today we had one ounce of Black soldier fly larvae from the original larvae harvester.  If you remember, Nico started the harvester with chicken waste solids and compost.  It’s now producing about two ounces a week.  There is lots of room for improvement.  I’ll write a blog post about the entire system, from Nico to where we are right now