Aquaculture with Wicking
A New Idea
RAWW System – Recirculating Aquaculture with Wicking bed System
Aquaculture with Wicking
The RAWW System integrates the well known systems of Aquaculture and Wicking into one unit, bringing the best of both worlds together to produce fish and vegetables and can be applied commercially or on a smaller scale.
Imagine having a year-round supply of fresh homegrown vegetables and healthy fish produced in a way that is easy to manage, uses far less water than conventional systems and that you can harvest anytime.
This exciting and unique way that I have personally tried and tested since 2018 brings together a plateful of fish protein with vibrantly healthy vegetables. I strongly believe that the RAWW system, with its consistent and ample supply of nutrient rich water and the warmth from the tunnel, creates a perfect environment for both the vegetables and fish to “do their thing” and thrive.
No matter where you are, or what kind of environment you are in. This is an exciting way of sustainable food production!
The R.A.W.W. System
The RAWW System merges the growing of fish in a Recirculating Aquaculture System with the production of vegetables grown in Wicking Beds containing SOIL with no separation between the fish component and the vegetable production component.
It is a closed system that combines the best of science with nature to grow food. Fish, stocked in the pond, enrich the water, which feeds into the soil of the wicking beds where vegetables are grown. All of this takes place in a tunnel which provides a protected environment.
Each installation can be customised to suit any space based on your specific need. From space in your back yard to conventional farming. The RAWW System is a wonderful way to grow nutrient dense food.
Fish Pond & Wicking Bed
The warmth of the closed environment creates an ideal temperature for your fish & vegetables to thrive in. With a RAWW System, vegetables receive all the richness from the soil (because they are grown in Soil)… PLUS the nutritious waste water from the fish.
The waste water, following the RAWW Systems unique design, flows through a mechanical filter, followed by a biological filter. This allows for the waste water to wick up through the wicking beds and creates a wet zone for the plant roots to absorb the nutrient dense water.
The water then completes its circuit back into the fish pond, returning purified and well oxygenated for your fish to continue flourishing.
In the wicking beds, the plant roots absorb the nitrates from the water, and minimal amounts of organic supplemental feeding is needed to produce an abundance of vegetables.
Why the emphasis on Soil and microorganisms?
- Soil essentially is what keeps us alive, it provides us with our basic needs of clothing, shelter and food.
- Quality soil naturally holds minerals and inorganic matter (derived from rocks).
- Organic matter (humus) is made from the decomposition of dead organisms found in soil.
- Organisms such as algae, bacteria, fungi and earthworms are naturally found in soil and play an intricate part in producing quality soil and therefore quality vegetables.
- Air and water, found in the pores between the soil particles, are essential for all plant life.
- Soil shows us the never-ending cycle of life (with no negative impact to the environment) by continuously breaking down matter and building it up into soil to feed plant life.
- Growing vegetables in soil is easy – there is no hard science involved. Occasionally adding good quality compost into your Wicking Beds, which is easily available at nurseries or hardware stores, is however important. The microorganisms in the soil (our superheroes), on receiving the compost, will breakdown the organic and inorganic matter into substances that are easily available to the plants. The synergy of soil, air, sunlight and water unite to support the intelligence of plant life to provide us with healthy vibrant food.
- Wicking is known to use far less water than conventional farming methods and because of the ideal climate in a RAWW System, the vegetables thrive.
- Growing your vegetables in Wicking Beds means that once the vegetable roots are established and reach the wet zone, there will be no need to continue watering by hand, leaving you to enjoy watching their rapid growth in this ideal environment.
Microorganisms
Being wicking beds, the plants thrive in nutrient-rich soil, bustling with powerful microorganisms that are key to the success of the R.A.W.W. System. Much like how they’re essential to our gut health, indeed, microorganisms form the foundation of all ecological systems. Think of friendly microorganisms as nature’s chefs, preparing a nutrient-rich feast for your plants’ roots. A healthy soil teems with 100 times more microorganisms than water. These microorganisms also act as architects, building robust soil structures that efficiently retain water. These marvellous wonders of nature found in healthy soil establish a solid basis for your plants to thrive in.
RAWW - How it all began
Farming Background
Coming from a horticultural and commercial farming background I have a deep understanding that in order to grow vegetables certain requirements are needed. For starters, a healthy soil teeming with natures microorganisms is essentially the foundation for growing healthy vegetables. Just as your gut needs a good healthy microbiome, so does the soil in order for your plants to flourish. A good water source is crucial as vegetables are composed mainly of water and thirdly, growing in a calm environment with little to no wind cannot be underrated!
Left Commercial Farming
Leaving commercial farming in 2016, I ended up in an area that was not entirely suitable for vegetable production. Its challenges were big – nutrient deficient sand to anchor my plants into the earth, a current drought in the area meant we all had to hold back on our water consumption and then the wind…. boy oh boy, the wind.
A few days of blasting wind not only leaves your veggies in tatters but sucks out any remaining water from the sand. What a challenge this was! And being from farming descent, my hands just ached to be in the soil and I needed to watch things grow.
But how?
I do have a strong belief that the answer always travels with the question. If we ask, wait and observe …. the answers do come. So, this was my big question that I put “out there” in 2017, how do we grow vegetables under these conditions?
the Wicking System concept
It wasn’t long before late one night my wife was scrolling through her Facebook and came across the concept of wicking, a system that is popular in Australia. This intrigued us and led us to a good session with google and being engrossed in learning about the many benefits of wicking. The fact that wicking beds use less water……a whole lot less, meant it was worth a try.
Going back many years now in the story, probably one of the first discussions I had with my wife when I met her, was my fascination and desire to farm fish.
Farming fish for me was all about finding a sustainable way of growing fish that didn’t face the challenges of fish raised in the oceans. I wanted to explore a viable way to grow fish as a healthy protein source. By growing fish in ponds, it meant that I could control what I fed the fish and keep an eye on the quality of the water. Having them in a warm enclosed tunnel, created ideal temperatures to keep the fish active and very hungry.
This led to the fish being harvestable at 9 months weighing an average of 500gram.
Combining my expertise
The next step was to combine my knowledge and love for growing vegetables with my curiosity of fish farming into one system that benefits each other.
My thoughts were on the nutrient rich fish waste, surely there must be a way to use this through the wicking beds in a continual cycle to benefit the plants? I played around with connecting the pond to the wicking beds and it all came together perfectly – initially calling her Fish and Wicks, we have now given her a more grown-up name of Recirculating Aquaculture with Wicking Beds System (RAWW System).
Using wicking beds for growing vegetables, I got to choose the type of soil I wanted to use, so I made sure I added plenty of organic matter and microorganisms (natures miracle workers) into the mix to get the soil suitable for the vegetables to flourish in. Minimal supplementary fertilisers and organic matter are added into the soil from time to time.
Problems Solved
My water problem was solved by recirculating the fish waste water through the wicking beds. The plants receive this nutrient rich water as it passes through the cleaning filters before returning back into the fish ponds. Very little top up water is needed, and none of the water goes to waste.
I can testify that wicking definitely uses far less water than conventional farming methods. Whilst the vegetables don’t get the rain, they do have a constant “on tap” supply of water through the wicking beds. I am amazed how the vegetables appear to grow quicker than in conventional farming ways and I love the fact that I can “push” the growing season of summer veg a little further in the warm tunnel environment.
My issues with the wind devastating my crops have gone as the vegetables grow peacefully in their protected paradise.
The RAWW System
The RAWW System is low maintenance and easy to operate. It is a well-thought-out uncomplicated recirculating system which is user friendly. It uses conservative amounts of water and utilises all the fish waste – a winning formula for water scarce areas while growing healthy fish and vegetables.
With Recycling, lower carbon footprint and healthy nature interaction in mind, the RAWW System will fill your gardening spirit with joy and your body with healthy vibrant food.
This has been an exciting process and continues to keep me in awe of the variety of vegetables that one can grow in this system whilst the fish are growing. I’m personally loving this Recirculating Aquaculture with Wicking bed System that is sustaining me and my family.
Frequently Asked Questions
Wicking Bed System Q&A
What is a wicking bed system?
A wicking bed is a raised contained growing bed used for growing vegetables and herbs. It holds a body of water underneath the soil and this water wicks up into the soil from below and feeds into the root structure of your plants.
It works opposite to the conventional way of watering plants from above. It is a water wise method of growing vegetables and proves to use a lot less water than conventional methods of growing vegetables.
How does a wicking bed system work?
Water is contained below the soil (like a reservoir), it is wicked up via capillary action into the soil. The roots of your vegetable have access to this abundance of water.
Does a wicking bed use less water?
Studies have shown that growing vegetables in a wicking bed system uses less water than conventional methods of growing vegetables.
Do plants grow better in a closed tunnel environment?
A tunnel covered in plastic holds the heat within creating a warm and sheltered environment. This sheltered environment is a good thing as wind can severely damage and set back the growth of your vegetables. The warmth in the tunnel means you can “extend” the growing season of your summer vegetables.
Is fish faeces good for vegetables?
The faeces of fish is composed of nitrogen, phosphorous, potassium, calcium and magnesium. Interestingly fish excrete ammonia mostly from their gills as part of their digestion process.
In a RAWW System, the fish faeces solids are held back through mechanical filtration (this can be used as a fertiliser on fruit trees etc). The ammonia in the water is then biologically treated, which makes it available to plants in the form of nitrates. Nitrates is a form of nitrogen and plays an essential part in healthy leaf growth.
What is the difference between nitrites and nitrates?
Fish excrete ammonia, bacteria break the ammonia down into nitrites. The nitrites are then broken down by another form of bacteria into nitrates. Nitrites consist of one nitrogen atom with two oxygen atoms. Nitrates consist of one nitrogen atom and three oxygen atoms.
What nutrients do my plants get from fish waste water?
From fish faeces you get nitrogen, phosphorous, potassium, calcium and magnesium along with several trace elements.
What vegetables can be grown in a wicking bed system?
Most vegetables and herbs can be grown in a wicking bed system. I’ve had success with leeks, carrots, butternut, aubergine, beetroot, all leafy greens, tomatoes, beans and a variety of herbs.
I have a healthy rue plant growing in the wicking system which I trim and drop around my vegetables as a form of pest control. A comfrey plant is thriving in my wicking bed too. This I chop and drop, or make a tea from, to add into the soil as a natural fertilizer. I also let stinging nettle grow in the wicking bed and make a natural fertilizer tea from it.
What are the disadvantages of installing a wicking bed system?
The initial set up of Wicking beds is expensive.
Do you use mulch in a wicking bed system?
Yes, a good layer of mulch is important. Not only does it provide food for the microorganisms but it also assists with water retention in your wicking bed.
What fertilizer can I use in a wicking bed system?
Use organic fertiliser such as bone meal, chicken litter, vermicompost, matured cow, goat, donkey, horse manure and well-made compost.
What soil is used in a wicking bed system?
The first layer is sand to assist with the wicking, followed by a good mix of potting soil and compost.
Advantages of a wicking bed system?
- Vegetables don’t dry out in a wicking bed as they have a constant supply of water to absorb through their roots.
- There is less weeds to control in this type of environment.
- Being raised beds, the vegetables are grown at a comfortable height.
- In a closed tunnel system with wicking beds, the temperature is consistently warm and protected from cold winds and excess rain.
Recirculating Aquaculture System Q&A
What is a Recirculating Aquaculture System?
A Recirculating Aquaculture System, abbreviated to RAS, is a closed circuit which continuously loops the dirty water from the fish pond through a filtration system that cleans and treats the water before returning it back into the fish pond.
What are the advantages of a Recirculating Aquaculture System?
A RAS, set up correctly, is an efficient and effective form of raising fish. Stocking density of your fish can be intensified according to the size of your filtration system.
What are the disadvantages of a Recirculating Aquaculture System?
There are many components which make up a RAS, this makes the initial set up cost expensive. The circulation and aeration pumps need a continuous supply of electricity.
How much does Recirculating Aquaculture System cost?
The size of the system to be installed will affect the price of the installation. An estimated cost of installing a RAWW System consisting of a tunnel size of 6metres by 10metres, comprising of a pond (3metres x 2metres) , and 2 wicking beds is ZAR150,000.00.
Which species are cultured in Recirculating Aquaculture System?
In a RAS system Tilapia, Trout & Catfish can be farmed. In the RAWW System, to date, Tilapia have been successfully farmed.
What is the difference between aquaponics and a Recirculating Aquaculture System?
Aquaponics is the combination of raising fish and growing vegetables in an inert media which gets nutrition from the fish waste and other nutrients added into the water.
A Recirculating Aquaculture System (RAS) raises fish only with no vegetable growing involved.
A RAWW System combines a Recirculating Aquaculture System (RAS) with Wicking beds, this means that the vegetables are grown in soil and receive nutrients both from the soil and from the fish waste.
What is the water quality monitoring in Recirculating Aquaculture System?
The following can be monitored in a Recirculating Aquaculture System - Dissolved Oxygen, pH, temperature and ammonia. All these will indicate the quality of your water which will affect the growth of your fish.
What is the main purpose of biological filtration in Recirculating Aquaculture System?
Fish waste is high in ammonia. The main purpose of a biological filter is to convert ammonia into nitrites, then into nitrates. This keeps the water clean and healthy for the fish.
What are the problems that you face when operating the Recirculating Aquaculture System?
These systems are built to be robust and user-friendly. But, as with all working equipment, regularly checking that the pumps are in working order is important as the system relies heavily on the circulation and aeration pumps to keep the system functioning at all times.
How do I keep my RAS functioning properly?
The RAWW Systems are built to be robust and user-friendly. But, as with all working equipment, regularly checking that the pumps are in working order is important as the system relies heavily on the circulation and aeration pumps to keep the system functioning at all times. Flushing and cleaning of filters habitually is necessary and checking on your water quality indicates the health of the pond water.
What is the principle of Recirculating Aquaculture System?
A Recirculating Aquaculture System is a closed recirculating system that comprises of a mechanical filter – for solids removal, biological filter- to turn the ammonia into nitrites/nitrates, a polishing filter – for fine solid removal and aeration and circulation pumps which create the necessary flow of keeping the water healthy.
The RAWW System comprises of the above filters and pumps with the inclusion of Wicking Beds. The RAWW System feeds the nutrient dense waste water from the fish to your plants.
How are solid wastes removed from a Recirculating Aquaculture System?
These are removed by a mechanical filtration which filters the solids out of the water and is collected in a tank. This must be flushed out frequently, and this nutrient rich fertiliser can be fed to fruit trees and such.
Why is it important to have a well oxygenated pond for growing fish?
Everything in life relies on oxygen to function. A well oxygenated body of water is a healthy body of water which benefits both the fish and microorganisms that clean the water.