Jul 17

Use Aquaponics To Save Water When Growing Food

A good book about the water crisis.


You can use aquaponics to save water by up to 90% when growing food. In these times of global climate change and frequent drought, it is very important for farmers to save water!

First and foremost, food is grown in the hydroponics section of an aquaponics system. It usually consists of vegetables and soft fruit such as tomatoes, melons, squash and cucumbers. In the usual sort of farming, you irrigate them once and then throw away the water. In aquaponics, you save water because this water is sent for cleaning to the plants and re-used, for growing food.

Fish are intensively farmed in the fish rearing tanks of an aquaponics system. However, unlike usual fish farming, you save water because the water used by the fish is cleaned by the plants and re-used, since it is miracle gro for growing food, and is not thrown away.

The fish are the source of the nitrates for the plants, and the plants clean the nitrates out of the water, so it can be recirculated clean back to the fish.  The water goes round and round like that. Growing food all the time at a tremendous rate!

The water is in tanks and hydroponic tanks made out of solid walls and lined with pond liner so they do not leak. You save water because the water you are using does not sink straight into the ground and flow away on the first use. It is used again and again for growing food.

None of the water in an aquaponics system soaks directly into the ground. It is kept and constantly re-used.

The water is also covered over and shaded by a shed over the fish tanks, and floating polystyrene rafts full of plants or at least two inches of growing medium such as expanded clay balls (hydroleca or hydroton brand clay rocks) which prevent the water surface heating up to evaporation temperatures.

Less than 10% of the water volume in the system is lost to the outside daily. Some, however, has to be used in a Deep Water system with floating rafts in it in order to flush out the fish poo from the filter into a settling pond for composting and subsequent dewatering.

Meanwhile, you can get five metric tons of basil and five metric tons of fish a year, just as an example yield (from the University of the Virgin Islands’s data on their commercial aquaponics system), off 0.05 of a hectare of growing space with aquaponics. By using aquaponics you save water, at 90% of the water you would otherwise had to have used to get the above results.

If you would like to download more articles from this site about aquaponics to read at your leisure, I have edited together the first six months’ worth of posts from this site into the ‘Aquaponics Global Anthology 1‘.  It is immediately available for download and printing out here: [paiddownloads id="1"]