Aquaponics Vegetable Garden
Opening in Summer 2020
To greatly reduce transport mileage and provide in our own needs, it was decided early 2019 to build Alladale’s own aquaponics vegetable garden. Construction started in June 2019 by clearing a reasonably flat area, roughly 1 acre in size. In October, the three main greenhouses were erect, which will house the fish, vegetables, and herbs.
The aquaponics growth system has been chosen, because it is now widely acknowledged that horticulture is an industry of increasing costs and diminishing returns where landscapes, both large and small, require constant chemical fertilisation. The fertilisers are derived of course from dwindling and polluting fossil fuels.
• Traditional horticulture is inherently unsustainable and systems are breaking down. Lifetime droughts are now common
• Pollinator colonies are breaking down
• Super weeds, resistant to even poisons that created them, are rampant
By introducing Aquaponics at Alladale, we hope to demonstrate real change and leadership in the exemplary production of food, namely:
(1) how to produce high quality food locally
(2) how to use locally
(3) how to support locally
(4) how to be local
We want to move forward using technological advances and scientific knowledge to produce food outside of natural ecosystems that can be done virtually anywhere it is needed. It is using
resources and ingenuity to produce food with almost no environmental impact, that can be done in almost any climate. Leadership in this field will demonstrate highly efficient labour use and only 5% of the water of traditional food growing systems.
The term ‘Aquaponics’ was coined in 1970’s as a combination of the words ‘aquaculture’ & ‘hydroponics’. Aquaponics is the cultivation of aquatic animals & plants in natural or controlled environments.
Hydroponics is the growing of plants without soil, using water to carry the nutrients. The term ‘aquaponics’ was created to designate the raising of fish & plants in one interconnected
soils system. Aquaponics can solve the major problems of both freshwater aquaculture & hydroponics.
The major problem in land-based aquaculture is that fish waste in the water creates continuously elevating levels of ammonia. If left unchecked, this toxic element will rapidly kill the fish.
The aquaculture industry typically uses one or both of two options to resolve the problem.
(1) a constant supply of fresh water to replace the toxic water
(2) expensive filtration systems
Neither of the above are ideal.
The former not only uses voluminous quantities of our precious water, but also creates equally large quantities of high-ammonia water that is toxic to any natural ecosystem.
The latter is simply very expensive. The high cost is especially pertinent to smaller commercial operations as most filtration units only make financial sense at large economies of scale.
Fish farms in natural bodies of water, often called “open net pens”, are rife with problems, notably their potential for negatively impacting wild fish stocks.
The major problem in hydroponics is the ongoing need for large inputs of fertilisers. A soil-less production system means all the mineral – all the food – required by the plants must be continually added. These fossil-fuel derived (“chemical”) are very expensive. Available organic fertilisers are not commonly used because they are less water soluble, thus more likely to cause problems & can be several times more expensive than their ‘chemical’ counterparts.
Hydroponic farms are a major water consumer as many use a drain-to-waste system. Even hydroponic farms that recirculate water must drain and replace their water regularly as they do not host a living ecosystem that balances itself.
By combining fish and plants into one system, aquaponics can solve the primary problem of both aquaculture and hydroponics. Fish waste provides a near perfect plant food and is some of the most prized fertiliser. The plants, using the minerals created from the waste, do most of the work of cleaning the water for the fish. The fish feed the plants. The plants clean the water. The symbiosis is as logical as it is effective.
The third living component in aquaponics is bacteria. The whole system hosts specific types of bacteria that serve two roles. One family detoxifies ammonia in the effluent by converting it into nitrates. Another family mineralises organic matter (primarily fish faeces and uneaten feed) by breaking it down into its elemental constituents which are usable by plants. Without this vital conversion in a closed system, both fish and plants would rapidly die. Establishing the bacterial cultures and monitoring their health is one of the most important tasks of an aquaponic farmer.