Backyard Aquaponics
A place to discuss aquaponics

Time for me to make a start on my "gunna-do' list and tackel one of the jobs on the list
The one I want to take on first is the issue of water usage in AP v/s ground gardens...

I don't imagine that it would take much to do the experiment. I would only use a small system to do this - I will use one 200L blue barrel as the tank (laid on its side with an access panel cut in the top) and another blue barrel cut in half to form 2 X 100L GB's.... It would be set up next to a ground garden which has the same surface area as the 2 blue barrel GB's combined.

In order to be a fair test, they would have to both be planted with the same number of plants and kinds of plants as well. They will also have to recieve the same amount of sun light.
To be fair the soil in which the plants grow should be in peak condition too (well composted and have a good population of earth worms) A well composted garden will retain water better too...

Have I missed anything - I am open to suggestions and correction

your AP beds would have to be cycled in order for a fair comparison if the soil bed is composted

There will be a difference between summer and winter i havent watered my dirt garden in weeks [ also havent topped up the aqua] .If you look at the enclosed photo the area of my dirt garden it equals the area of the grow beds .The soil in the dirt garden is the best you can get .Over summer the dirt garden had to be watered every day hose running 10 minutes the aqua needed to be topped up every fourth day hose running 10 min . You will find every situation is different [ Hope this helps ]

every bit helps mate _ the more of us who do this experiment the more info and proof we have

The topics of summer and winter watering was raised here at home after I posted the last post... So I would have to have the system over a period of time to get fair and accurate readings...

As far as cyceling... that is not a problem as I would take water from the 4000L of water I have in the other systems to start the system

And that set up looks great mate!!

That shot was taken a while ago [just to show the layout] will do a series as soon as the glasshouse is on line

Hi AM,
Feel free to move my other post from your system thread to here if you like.

The only things i can think of are, the soil be well cultivated to the same depth as the growbed and the soil area should have a boundary extending downward to prevent lateral root growth outside the designated area.

AM F&F is correct, but in my opinion water use is water use regardless of if it comes from the sky or from a tap.

Obviously the AP system's finest hour is during a dry hot summer. THAT would be the test period i'd use. AP water "use" may be close to dirt use during a winter, but dirt will never be better.

Just as an aside............i potted up some fruit trees into some REALLY big pots 2 weeks ago. We have had no rain for the past what, 3 or 4 days, but its been BLOODY FREEZING. Checked the pots today........very dry. and that was with a layer of straw over the dirt.

HEX made a VERY good point.

I'll expand on it.

AP veggies grow faster and bigger. we know this.

So for any experiment to have true value it would have to be on litres per kg of tommies, for example.

Otherwise you'll have a situation where you'll have half the yield from your dirt plants to that of your AP plants. More vegetation = more transpiration = skewed results on AP water use.

make sense?

My evaporation rate was very high for the past 2 weeks which have been bone dry... I was losing more water to the marine studies students system every day, but when you see the mass of green plant matter which is dependant on the one tank which feeds that system you begin to understand - there is a HUGE amount of transpiration and even guttation taking place (not to mention evaporation )

don't forget the wet and dry seasons are opposite for southern Australia and northern Australia, so Steve's cold wet winter would be up against the cool dry winter in North Queensland, and then the hot dry summer against the hot wet summer.

I think the soil plot will be more difficult to control with all the variables.
AP will lose moisture to the air via evap/transpiration, but the soil plot could lose it to both the air (evap/trans) and the surrounding soil via capilliary action.

It might even gain some moisture by the same method which would be hard to quantify.

This is part of why AP is said to be better than traditional methods of gardening as there is no loss of water to surrounding areas which are in effect unproductive zones...


It they are gaining water from the surrounding soil I would assume that there has been rain - that would mean that the 2 GB's and the tank itself would have acted as collectors and stored the water instead of the water peculating away to the water table below, out of the reach of the roots of most veg...

CSIRO would be the ones to actually get the proof in numbers, I think that as Hex says, too many variables and not enough equipment for home testing of soil moisture, temp, evap/trans etc

I only want to do an obvious, uncomplicated test to see which would need more water...
If its raining, neither needs water... the AP system stores the extra water where the soil garden loses it to the surrounds...
If it is dry, the ground garden loses water to all the same places as the AP system, but the AP loses water in less ways than the ground system...
At the same time we could see how well the plants grow - how fast they grow, how strong etc etc etc