INTRODUCTION TO AQUAPONICS

How to Grow Food in Small Urban SpacesGraham Wood

1 WHAT IS AQUAPONICS?

Aquaponic food production combines soil-less vegetable growing (Hydroponics) and fish farming (Aquaculture) within a closed recirculating system.

Aquaponic systems mimic the natural waterway ecosystems and comprises a highly effective growing method for indoor food production.

ISSUES WITH TRADITIONAL FOOD GROWING

Dwindling fish

stocks.

Oil based fertilisers.

Genetically modified.

Soil depletion.

Water shortage.

Deforestation.

Food miles.

Climate change.

2 PLANTS

Majority of vegetables can grow in Aquaponics.A variety of crops can be grown -- Lettuce, Spinach, Chard, Cucumbers, Kale, Spinach, Rocket, Watercress, Basil, Peppers, Tomatoes, and Strawberries.

When starting a new system it is better to grow a variety of salad crops until your system is more mature.

In Australia they have even grown fruit trees.

3 FISH

Factors that contribute to healthy fish are: Temperature Water quality (pH & Ammonia) Food.

Fish are fed, they digest and break down the food producing waste by excreting ammonia through urine, faeces, and gills.

Usually recommend using Gold fish or Carp if starting off in Aquaponics as they are the most robust fish and produce large quantities of ammonia which is ideal for Aquaponics.

4 NITROGEN CYCLE

The Nitrogen cycle is the most significant process within Aquaponics as it is responsible for the conversion of fish waste into nutrients for the plants, and without this process, the water quality would deteriorate rapidly and become toxic to both the fish and plants.

Nitrogen gas (N2) is 78% of the atmosphere, and plant and animal cells need nitrogen to produce proteins, nucleic acids, and amino acids.

Nitrosomonas bacteria converts ammonia (NH3) into nitrite (NO2) and then the Nitrobacter bacteria converts the nitrite into nitrate (NO3).

Nitrate is a very accessible nutrient source for plants.

5 AQUAPONICS SYSTEM

Variety of Aquaponics designs that are used in both commercial and hobbyist settings. The most common systems in usage. NFT (Nutrient Film

Technique) – used mainly in hydroponics

Flood & Drain system – (most common hobbyist system)

Raft system – (most common in commercial systems)

5.1 NFT (NUTRIENT FILM TECHNIQUE)

NFT can be hobbyist or commercial, but is the least commonly used with aquaponics. The plants are placed in pots and a small amount of water (or a film of water) is trickled through the base of the channel from which the roots access the water.Can be layered vertically and wall space can be used. It can also be extended very easily and is the lightest in weight.

5.2 FLOOD & DRAIN SYSTEM

Most common design used in hobbyist systems. Grow bed filled with a ‘grow media’ normally consisting of either gravel or clay pebbles. Plants are planted directly into the media.The grow beds are flooded and drained periodically, allowing water to circulate through the system on a regular basis.

5.3 DEEP FLOW OR RAFT SYSTEM

Deep flow/raft is mainly used for commercial or larger systems. The grow beds are essentially long troughs of water, the plants sit on rafts made from Styrofoam with holes for pots to allow the plants to sit with their roots immersed in the water.

Restricted to salad vegetables as the weight of larger plants such as tomatoes and cucumbers cannot be supported easily on the rafts.

6 ADVANTAGES OF AQUAPONICS

Enabling self-sufficiency Providing household self-sufficiency of fruit and

vegetables.

Conservation of water Maximum water conservation due to water reuse and

recycling.

Efficient use of land Elimination of need for agricultural land to produce

similar crops.

Preserving the environment The overall reduction of environmental footprint for

crops.

Natural fertilisation Organic fertilization of plants with natural fish

emulsion.

Low Maintenance Aquaponics is very low maintenance compared with

todays ground Agriculture, Horticulture, and Aquaculture.

PRACTICAL HOME AQUAPONICS SYSTEMCan provide the average sized family with fresh leafy vegetables all year round, with the possibility of one or two edible fish per month as well.