23/05/2026
The fringe benefits of Flood & Drain irrigation!
Bell siphons are a great example of fluid mechanics, but very troublesome, with no way to control when they prime; the more siphons you have the bigger the problem!
So we designed made & use our own ‘invention’ which used Daniel Bernoulli’s principle (another example of fluid mechanics); with a float switch inside the siphon to trigger the siphon controller to turn the pump(s) on & off; a monumental game changer!
Once you’ve got full siphon control it opens a world of options, to enjoy the benefits of F & D:-
1. The obvious . . . It’s automated.
2. Less obvious; if the bed is made correctly, F & D eliminates all anaerobic issues (the main problem with wicking beds).
3. Even less obvious, F & D aerates the soil . . . As the bed floods, it expels air from the soil, replaced with fresh air as it drains; that ‘fresh’ air is 80% nitrogen . . . so, the micro-biology in the soil get all the nitrogen it needs to convert into bio-available nitrogen for the plants, negating the need for any ammonia from the fish or synthetic nitrogen fertiliser. All you need is an abundant ‘organic’ population of ‘natural’ micro-biology!
4. OK . . with no need for fish . . . there’s no need to 24/7 F & D, a couple of cycles each day is just enough to irrigate, fertilise and aerate the soil!!!
5. Nitrogen is the main nutrient required, but we do need more; so . . . add a worm farm! Set the worm farm up so it gets a ‘trickle’ of water through the farm and back to sump; the worms are kept moist without flooding; the nutrients get flushed back to sump, then circulated by the F & D to fertilise the plants for free!
Summary
• The best thing to come out of Aquaponics is F & D; the rest is a waste of time, money & effort!
• A wicking bed is little better; it’s only a watering system, there’s little if any aeration, and the soil needs regular nutrient replenishment!
• F & D is 20% irrigation, 30% free fertilising, thanks to the worms & 50% aeration . . . nitrogen for the plants, oxygen for the micro-fauna!
The system we run has three gold fish, more for aesthetics than function, running two F & D cycles per day; total run time, twenty minutes per day, a saving of 98% compared to a traditional 24/7 aquaponics setup.
Factor in the costs of buying, feeding & managing high stocking rate fish, & the inevitable mortality with fish farming & you have a recipe for an expensive, high maintenance, & anxiety grow system, that's still has a nutrient shortfall!
The system we have occasionally gets some dolomite lime, the rest of the nutrients come from the worms!
We run the system costs 30 cents per month to run, run on mains powered 12 volt, 100 watt, switch mode power supply,!
Don’t be put off by the need for a pump for each grow bed; the benefits outweigh the cost; an up side; if / when a pump fails it doesn’t take the whole system down; simply ‘bridge out’ the affected grow bed until it can be fixed or replaced; everything else continues on as per normal!
