Jun 10

Aquaponics For Schools

lettuce seedlings in the UVI aquaponics system

Lettuce seedlings in the UVI aquaponics floating raft system.

University of the Virgin Islands commercial tilapia aquaponics system

University of the Virgin Islands commercial tilapia aquaponics system

To any ambitious biology or business teacher, a small commercial aquaponic farm is a priceless gift.  In any large flat roofed school building, you can have one on the roof and the students can run it as part of their classes, since it is automated largely.  But keeping an eye on the aquaponic organic food factory on the roof will teach them more about real biology, farming and agribusiness than any number of textbooks.

It may also provide the school with a much needed source of income in these interesting times.

But what is aquaponics?  Aquaponics is intensive fish farming in tanks married to intensive vegetable farming in tanks.  So you should know all about fish and plant biology as it applied to intensive aquaculture and hydroponics. This gives your students first-hand experience of looking after a natural ecosystem in an artificial container.  You also should know how to keep the water quality good enough to suit the plants and the fish. Chlorinated water cannot be used, since the disinfectant in the water kills the bacteria that make the fish waste into plant food, see the diagram below.

aquaponics flowchart

Aquaponics system biology flowchart

Fish excrete ammonia. Nitrifying bacteria in the filter part of the aquaponic system convert the ammonia to nitrates.  The nitrates are absorbed by the plants, and the plants grow really fast. This makes the water clean. The water is pumped back to the fish to be used again.

In aquaponics, only 1.5% of the water is lost in a properly designed and run aquaponics system. So it is very good for saving water on the farm. In aquaponics, plants can grow up to twice as fast at half the usual spacing. So you get up to twice as many plants, twice as fast, compared to farming in soil. But this can only be done if you have the right aquaponics system and the right training. As with any business, proper management is very important.

You will also need to know how to run and clean water pumps, air blowers, and alternative energy sources such as wind and solar generators.  You need a cheap source of electricity to run the machinery of your automated aquaponic food factory on the roof.

YOU DO NOT NEED SOIL IN AQUAPONICS. You only need water. And you do not waste any water.

Because you do not need soil, only tanks of water, you can do aquaponic farming anywhere, like on the school roof, as long as you have electricity and somewhere to put the tanks, the pumps, the air blowers, and the plumbing.

In the tropics, you do not need a permanent greenhouse, though in places like Hong Kong where the temperature goes down a lot in winter, you will need temporary plastic hoop houses to cover your aquaponic systems and also to protect them from typhoons. These have to be quite strong to keep the wind and rain off the system. For example, lettuces do not do well in temperatures below 10 degrees centigrade and above 20 degrees centigrade they start to die.

Pictured below is a gravity feed version of a small aquaponic system. You would need something larger than this to make the farm economically viable, but this give you a basic idea of what can be done with recycled materials and a tank or three.

Usually the first fish you use to make the fertilizer for your plants is the tilapia fish from the Nile originally. It is one of the most commonly farmed fish in the world. It is a tropical fish and does not stay alive in water below 19 degrees centigrade or above 30 degrees centigrade. You will need someone on your team who has kept tropical fish before and knows how to look after them!  If you live in a cold climate you will need to have some equipment to heat the water to the proper temperature and keep it that way.

Tilapia fish

Tilapia fish

gravity feed aquaponics system

Gravity feed aquaponics system

No fertilizers or pesticides can be used in an aquaponics system. They kill the fish! Instead, the fish water contains the nutrients that the plants need, and the pests can be controlled using biological methods.

Biological pest control methods include using friendly insects such as lady bugs to eat up all your aphids, also called greenfly.  There are also parasitic wasps and lacewings which also eat other pests as well. You can buy these online and they come in suspended animation in little blister packs. You spread them out with a camel hair paint brush so as not to damage them, and lift them onto the areas where the bad insects are eating your crops. That’s it!

Another way to get rid of pests such as caterpillars is to use a bacterium called bacillus thuringensis. This comes as a white powder which you spray on. It makes the caterpillars sick so they die, but is harmless to fish and people.

Here are some aphids and the ladybugs that like to eat them:


Aphids eating a plant



Ladybugs, ladybirds

You can also use harmless fats and oils to drown the insects that are eating your plants. But no insecticides or pesticides. They really do kill the fish, even if they are labelled ‘organic’!! You can be sure that none of the children will get poisoned by aquaponics for schools.

There are no weeds in aquaponic farming systems, so you do not need to use herbicide. So aquaponics for schools is not a toxic or dangerous activity.

There is no digging in aquaponics, and you can put the grow beds and raceways for the floating rafts up on tables and stands, so even people with bad backs can and do farm with aquaponic systems.

You can do all the work you need to do, including regular testing of the water to make sure the pH and other factors are correct, in a few hours a day. Your aquaponic systems are low tech mechanical systems with fish and plants growing in them. You have to make sure the fish and the plants have the best growing conditions. This sometimes means adding garden lime or potash to the water in tiny measured quantities to make sure that the water stays at a pH of around 7.0, or neutral.  This is something to do for your biochemistry classes. Looking at the kH and hardness of your water supply and other features of water quality analysis will give them lots of practical experience of how classroom work applies in the real commercial world of fish farming and modern recirculating aquaculture.

But before you go ahead and construct your own school aquaponics system, you need to look at all the business side of aquaponic farming in your area and do a business plan. If you cannot sell your fish and vegetables, you should not grow them!  Aquaponic systems can produce up to four times as much food for the space used, compared to conventional soil farming.  1/16 of a hectare of rooftop space can produce around 5 metric tons of fish and up to double that of vegetable plants a year. That is a lot of food to not be able to sell locally!  Schools that have their own aquaponic systems need to be sure that they are not going to have a lot of food that is simply rotting on the roof.  This is also very intensive fish and vegetable farming.

Market research is the first thing you do when you want to start a business, and aquaponic farming is a business. Aquaponic systems are very efficient food factories if properly managed and operated. This is something really interesting to do for your business class as a project. From your market research in local shops, markets and restaurants you can work out how much food you need to grow to cover the expense of constructing and operating a commercial aquaponic farm on the roof of your school. So then you can work out if there is enough room on your school roof for a big enough farm to cover your costs and perhaps make a bit of a profit. Aquaponics for schools is not aquaponics for fools!

If you are considering this kind of small commercial aquaponic intensive fish and vegetable farm on your school roof, please get in touch with us here

Call me! - Charlotte Appleton: Offline

» Get Skype, call free! and we can help you set this up correctly over Skype for a reasonable fee. If your farm is very big, it might be worth your while for a consultant to come and oversee the installation of your farm and the first few months of the business.  Aquaponics for schools can become aquaponics for whole communities.  If you get the whole community involved in their intensive fish and vegetable farm on your school roof, the sky is the limit!

Aquaponics Global Anthology 1 is available for instant download and to print out here: [paiddownloads id=”1″]

Feb 11

Looming World Famine Due To Speculators And Failing Agriculture.

You may have noticed that the price of basic foods keeps going up. You may hate thinking in percentages, but do the maths. Are your wages going up at the same rate as food prices?

If you are a farmer, are you getting the prices for the food that you grow, to afford the wages to keep pace with the rising cost of living? Could the land you are farming be intensively farmed enough using the methods you are currently using, to provide an income for you and your family adequate to cover food and living expenses at the current rate of price inflation? Is the agriculture you know sustainable and viable commercially? In the long term? Are you in sustainable food production? Please do the math!

The results of your calculations may well turn out to be disturbing. But what is happening here, in the West, has already happened in North Africa (the riots and revolutions were to a great extent sparked off by FOOD PRICES, since they could no longer afford to eat properly), much of Asia, South America, etc, etc…  Their agriculture is out of synch with basic incomes.  There is no sustainable food production in many of these places. Some of them have devoted so much acreage to export crops they have not grown enough to feed themselves!

People can’t afford to eat a balanced diet. In many of these places, it isn’t that the food isn’t available. It is that it is becoming too expensive.  Essential parts of a balanced diet, such as fresh fruit and vegetables, are becoming beyond many people’s means.  Organic food is often imported, and some of the most expensive food is organic.

There are two factors conspiring to cause this hike every year in food prices. One is climate change, which is afflicting farmers worldwide with weird and wild weather, droughts, floods, storms, and plagues. This is causing crop losses. Which means a lot of food that was exported worldwide, just isn’t now. It no longer is there to be trucked out.  Agriculture as conventionally understood has failed in these places miserably.  It has often become unsustainable, and people in these places have no source of sustainable food, let alone organic food.

The other factor is that certain deregulated banks, once banned from doing this, are now buying up food stocks and hoarding them until the price of these foods (corn, sugar, soybeans, wheat, and other staple crops) goes up enough for them to sell them and make a huge profit. Banks do not care if people starve because of the artificial scarcity of food they are causing. Banks like the scarcity. It puts up the price and they make more money. Banks are in business to make money, not to provide us with affordable food. The worldwide commodity markets make imported food sent to your country much more expensive than it should be.  But why is agriculture in your country so inefficient that you have to import food in the first place?  Imported food is expensive food!  Some of the most expensive imported food is organic food.

Even in London, England, where I live, doctors in the poorer districts are now coming across children with the distended stomachs usually seen in Oxfam photos of African famine disasters. This stomach distension is a common symptom of malnutrition. It is not that these children have not eaten, it is just that they have been eating a poor diet with not enough vegetables, fruit, and high quality protein. High animal feed prices mean that meat has become a luxury in many poor households. Coupled with ignorance about dietary nutritional values, a diet of breakfast cereals, bread and jam can soon lead to health problems.  Half of the food we eat in the UK is imported food.  This puts up real food prices on food such as fruit and many vegetables.  Why can’t we do more of our own food production?  And why can’t we grow more organic food?

However, there is a sustainable food solution waiting around the corner. Much of the food which is most expensive is imported or in the case of locally produced meat, fed on imported animal feed. Yet new food production technologies for growing good clean food locally in massive quantities, with few expensive inputs, and on a much reduced necessary area, exist. Each city district could be using disused land and derelict buildings to grow all their own vegetables and fish, reducing the need for expensive imported food and trucked-in food.  These sustainable food production technologies also use few staff, and should make locally grown food less expensive than imported food.  It’s urgent that we decrease real food prices.  Otherwise we will soon be paying the price of our folly in lives!

To make this sustainable food production technology more popular, a shift in dietary tastes needs to occur. People should be eating more sustainably produced freshwater fish such as tilapia and trout rather than the heart-unhealthy fatty meat and similarly unhealthy stodge they susbsist on today, to their wellbeing’s detriment. Eating more sustainably produced farmed fish would also help ocean fish, which are in danger of disappearing. Cheaper, fresher locally produced organic vegetables, eaten regularly, would prevent a lot of people from getting sick.  Organic farming may be part of the solution, but it is doubtful whether organic farming as conventionally understood can produce enough food to get places like the UK unhooked from unsustainable imported food. However, there are food production technologies that can be certified organic, even though they do not use soil at all.  You don’t need soil to farm organic food. You just need water for sustainable food production!

One of these local organic food production technologies, which translates well into an efficient and emission-free urban agriculture method, is called aquaponics. Established research at the University of the Virgin Islands in the United States and elsewhere has proven that, using aquaponic agriculture, you can grow five metric tons of tilapia and at least that much in vegetable biomass (given properly trained management) on 1/8 of an acre (1/16 of a hectare) in a year. This is done without using any soil, artificial fertilizer or chemical pesticides at all. All sorts of crops can be grown, including high-priced ones such as basil and other culinary herbs, also fancy lettuce, tomatoes, cucumbers and melons. The quality of the produce is very high and cropping is continuous on a ‘conveyor belt’ like system of floating rafts.  Food prices for all this food are affordable, and the food is locally grown and sold locally, so it is fresher.  This organic food is used as soon as it is harvested, and never gets into the hands of speculators and banks.  It’s time we separated food production from food speculation!

The fish water feeds the plants and the plants in the hydroponic part of the aquaponic system clean the water for the fish. Most of the water is recycled in this form of agriculture. If you are keen to save water where you farm, aquaponic systems run in series can save 90% of the water you are currently using, to grow much more food per hectare, all year round in many cases. This means that with proper management, you can get a fast return on investing in your new aquaponic system and training, in as little as two years from turning on the pumps. After that, with continued close attention to standard operating procedures, you should soon be going into profit with this method of sustainable food production.  This is a very efficient and clean form of agriculture.

Here at Aquaponics Global, we can help you do this, either over Skype or on a residency. We also conduct seminars and lectures if you would like to get together with other farmers in your area to invite us over on a tour to show you first hand what this is all about. It certainly isn’t rocket science but it DOES take a bit of retraining. If you have never looked after fish before, there is a lot to learn. And what fish would sell best in your area? Would you be able to shift 500 tilapia at a time? Should you kit up (and budget) for the more expensive trout production cycle instead? Considerations like this need to be taken into account. That fish water for the plants can’t be obtained without farming the fish! I am talking about intensively farming several thousand fish sustainably in the same system with hydroponic vegetable production.  This is about maximum food production for minimum inputs in minimum time using minimum space and water.

Call us, leave a message or book an appointment to call if you are intrigued by the possibilities of this agricultural revolution. It’s called the Blue Revolution and it’s certainly here.

To learn more about aquaponic farming and how to construct and operate your own aquaponics system, I seriously suggest you read the following books, which also include a volume about how to build your own greenhouse, in which to do aquaponics in a cold climate: