A peek into the fish tank - aquaponics explained

It has been well over 6 months now since the hydroponics system was first set up in the Permapatch Community Garden. And what a success it has been! Rows and rows of fresh crunchy lettuces in all shapes and colours.

And - despite us knowing that growing strawberries in Sydney (and a garden full of magpies) would always be a challenge - we even harvested a small crop of strawberries. 

Shannon and Anthony are our aquaponics specialists and together with Trevor from HydroMasta, Colin, Roman, and many other helpers in the garden they have put hours of sweat, love, and quite possibly a few tears into the beautiful system.  What started out as hydroponic (when we added nutrients manually) turned aquaponic earlier this year. In March, fish were introduced into the system and their waste now provides the nutrients. 

Asked what kind of fish we have, Shannon explains that we have silver perch in the system. Silver perch were selected because they can handle some temperature variation and high nutrient conditions. We have been running the system with only 100 fish to start, to make sure that everything works. It will take approximately 12 month for the fish to reach plate size and be ready for eating. As they are predatory fish, we can't add any more to the system as they will eat the younger fish. We will monitor the nutrient loads in the system while the fish are growing and determine how many fish we think the system can ultimately handle. 

Shannon adds that silver perch are highly adaptable fish that don't require sunlight, so they will feel comfortable in the tank. The fish are fed to provide them with the main nutrients they need. They also eat algae, which will grow within the tank. We've also included a couple of oxygen stones in the tank, to keep dissolved oxygen levels high. 

So how exactly does it all work? There are two main components - a fish tank and a plant bed. Nutrient-rich water from the fish tank is pumped through a bed where plants take up the nutrients to grow.

When we feed the fish they excrete waste, either in form of solids or solubles. The solubles can eventually be taken up by plants, however we don't want the solids to accumulate. Therefore a clarifier has been designed to create a centrifugal swirl. It drives the solid waste to the bottom of the blue tank. Take a look at the diagram below - in the middle you have the green fishtank and the blue clarifier. The solids settle down in it and can be removed by opening the tap at the bottom. The clear water above the solids is returned from the clarifier to the fish tank.

Let's follow the nutrient-rich water as it is pumped to the plant bed. On its journey, ammonia is dissolved in the water. However, in that form the nitrogen is not available to plants.  Bacteria help convert it first to nitrite, then to nitrate, which can be absorbed by the roots. With nitrate removed, clean and healthy water is circled back to the fish to live in.   

The principle is fairly straightforward, however getting it all up running and ensuring it remains in balance for happy fish and happy plants is no easy feat: every morning and evening our tireless helpers on the chicken roster also feed the fish - a big thank you to everybody involved! 

We all can also help ensure everything is running as it should be. The easiest thing to check is that the pump is running - it needs to be on always. If you notice for example that the water is no longer flowing, that there is a leak or anything else a bit "fishy", please notify the aquaponics crew immediately: Colin on 0411 578178.

Of course, the happiness of fish and plants is regularly checked. In addition to everything else, Colin is monitoring nutrient levels. It's all  a question of balance. For example, in winter when plants grow more slowly and also fish activity decreases, we can halve the amount of food given to the fish. Growth and therefore feeding will pick up again, come spring.  

A big thank you to Shannon and Anthony for providing this information. We look forward to many more lettuce harvests. 

Transformation task force PermaBee

It is not often that a Sunday working bee truly transforms the face of the garden. However, last Sunday's (19th April) working bee achieved exactly that.

The upper garden had always been reminiscent of its past life as a car park; and despite luscious private plots it never quite managed to acquire the same cozy feel of the lower garden. So a few months ago, the plan was hatched to cover the bitumen surface with woodchips.

Woodchips would not just be a cosmetic enhancement. They would also help to keep the upper garden cool(er) in summer and encourage beneficial ground and fungal networks to grow. And, all of the energy that is used sweeping the upper garden's surface clean of leaf litter and bark strips could go into proper gardening activities.

How many woodchips does it take for such an endeavor? MOUNTAINS of woodchips! 

  Colin at the summit of Woodchip Mountain

 Colin at the summit of Woodchip Mountain

And of course, it takes people to move the mountains.  Given the scale of the project, we asked Permaculture Sydney North (PSN) to lend us a helping hand and called a special Permabee working bee. This meant instead of our usual afternoon shift of a couple of hours, we started early to make the most of the day.

And things progressed really well! By the time we gathered for late morning tea the mountains had already been eroded to mere speed bumps.

                     Time for morning team - catching up with old friends and making new ones.

                    Time for morning team - catching up with old friends and making new ones.

Not that there we were short of tasks...There is always something to do in the garden. A whole range of activities had been planned and prioritised for the day:

  Our impressive project schedule for the day. After number 9 we ran out of white space on the board...

Our impressive project schedule for the day. After number 9 we ran out of white space on the board...

Excitingly, about 400 new seedlings had arrived just in time for the working bee. We received a mix of little lettuces, cabbages, carrots, coriander and several others. So not only would we be able to refill the lettuce pots of the acquaponics, the common beds had been weeded and topped up with compost the Sunday prior - perfectly prepared to provide for the little seedlings. 

Tasks like these cannot be tackled on morning tea alone. Since the early morning we had fired up the pizza oven and served pizzas for lunch. 

We're certainly getting the hang of how to get the pizza oven going, and even used the residual heat for roasting corn cobs and a slow-cooked pork roast. 

Activities continued well into the afternoon, until the wind picked up and temperatures dropped announcing a change in weather. Time to clean up and pack the tools away!  

It had been a wonderful day, - very productive in terms of all the tasks we accomplished. But most importantly, it was really fulfilling to work alongside like-minded people and have a great time turning our garden into an even homelier place. Thank you to everyone involved! 

It's raining again!

Oh, and what a washed-out Easter weekend it was! It seemed the garden's new rain gauge had just gone up in time to measure and confirm the weatherman's forecast of "Sydney will be wettest on Saturday with some suburbs recording above 50mm..." - it read 52mm of rain on Saturday evening. 

The garden's new rain gauge - nice and dry (not for long)

The rain gauge is mounted on one of the tall poles bordering the strawberry plot in the upper garden. You can't miss it when walking along the wall bed towards the caravan.  

There is of course a science behind correctly measuring the amount of rainfall. The Bureau of Meteorology explains the details and how the professionals do it. In the garden, we're interested in getting a better idea of the amount of rain the beds receive. Sydney showers can be quite local, and sometimes a "massive downpour" in one suburb might not mean a lot of rain for the neighbouring one.  It'll hopefully also help our kind watering volunteers to assess whether they need to give the communal beds an extra drop. 

So how do we keep track of the rainfall? Ideally, we'd start each early day with an empty gauge and meticulously check the amount of rain in the gauge at a given time later the same day. Practically speaking though we won't have a rain gauge roster ;-)  As with most things in the community garden, the rain gauge is there for everybody to take measurements. Next time you take a read, why not share it on the white board? Or leave a comment here on the blog? 

We hope you enjoy keeping an eye on the amount of rain the garden gets!

Pizz'stralia Day

On Sunday 25th of January, we once again took refuge in the garden to get away from the flag waving masses at our Pizz'stralia Day Pizza Feast. What a lovely way to spend this patriotic weekend, amongst our lush garden and and even lusher gardeners! Lots of people came along and brought all sorts of delicious ingredients with them including our ex-president Jonno, who brought some gorgeous fresh dough... 

There were sumptuous salads from the garden and pizzas smothered in forests of basil and tomatoes from the garden.

Happy Pizz'stralia Day!

This was our first big event for the year and it was delicious! The pizza oven is amazing and a great addition to the garden community.

Wood-Fired Pizza Oven Progress Report

Who doesn't like pizza? When I eat pizza, I feel as though the chaos of the universe all falls into place; it finally all makes sense, everything is at peace.

It has to be good pizza, ...though everyone has a different idea of what this constitutes. A victim of personal subjectivity, pizza can be a fraught territory, like talking about religion or politics. From the scandalous, yet tasty, Hawaiian, to the purist and minimalist Margherita, even the shape of the pizza can cause conflict among otherwise peace-loving people. 

Cheesy, tomatoey, garlicky, basil-y. Hot and crispy, paper thin, the point of the slice yielding and drooping slightly with lush delicate ripeness. That's how I like mine! Others disagree.

The one thing we CAN all agree on however is that pizza is awesome. 

It's taking shape and is almost finished, our long awaiting dream Wood Fired Pizza and Bread Oven.

Yesterday Andrew and Gary completed the arch and flue for the oven and the final bit of building is this week, when they install the insulating silicone based fire blanket, and render the dome to a fine finish.  The area around the oven will be tiled to provide a clean, washable and smart work surface and then early next week will see a first firing of the oven to put the final cure to the beast.

Soon to follow, an opening event to Christen the Oven. Get your finest pizza dough and sourdough’s underway, there will be a taste test competition for best base, sauciest toppings and best overall pizza chef. Game on!!

Pizza Oven - The Dream Becomes Reality!

Its almost here, our long awaiting dream Wood Fired Pizza and Bread Oven .

Today was a significant step forward with the final delivery of the dome for the Calabrese Courtyard Oven. Now the 3D Jigsaw and build by numbers process has commenced. Go to the website to see how the oven can be crafted to suit .

Today saw the delivery of the dome which weighs 240kg or so, and location in position on top of the firebricks and insulation board

This lift and location could not have happened by myself and Colin, Jo and Roman, the regular BOB the builders made herculean efforts to lift 1m high into place.

Don’t just wait though, in the next few days we will need to decorate the oven in our unique PermaPatch Style.




Aquaponics - A Breakthrough!

After some delays and several obstacles, our hard working team, with the can-do, must-do and will-do attitude have gone above and beyond the call of being great dudes and here we are; finally seeing the completion of the much hyped, eagerly anticipated PermaPatch aquaculture system! 

 He who holds the hammer.

He who holds the hammer.

The day began slowly due to a comprehensive and robust discussion regarding such weighty subjects as the weather, measurements and positioning, all important parameters worthy of intense debate when embarking upon these complex tasks.

 Making progress... Jo, Colin and Ivan

Making progress... Jo, Colin and Ivan

The A-team was joined today by Jo's nephew, Ivan who was visiting all the way from WA. Thanks to Ivan for coming along, it was nice to have some agreeable help!

 The totally awesome crew of high achieving PermaPatchers, Roman, Colin and Jo.

The totally awesome crew of high achieving PermaPatchers, Roman, Colin and Jo.

So finally......         


This aquaponics table can support up to 120 plants, with the water flowing through the trays and back to the fish tank... a virtuous circle indeed. The plants are fed by the nitrogen from the fish waste and in turn the water is oxygenated, ad infinitum. :)

Do visit the garden soon to marvel at this rather incredible development. 

Aquaculture WIP Report

Do you remember the aquaculture system that we had installed in the garden?  We removed it early this year.  It was composed of a couple of bathtubs and a tank containing yabbies and goldfish that pumped up through the hydroponic food garden. It was donated to the garden by our members Anthony and Shannon, who had previously had it installed on the balcony of their apartment.  Quite a genius setup!!

The good news is that, as you may know, aquaculture is coming back to PermaPatch in A BIG WAY! Lane Cove Council gave us a grant that has enabled the garden to build a cutting edge, state of the art aquaculture system, and it's all been built, designed and, in the future, used by members of the garden.  

If you have been the garden recently you may have seen Colin, Roman and Jo working really hard at getting this job done. Jo has provided so much expertise and labour to the construction of the system and we are so grateful to members and patrons who donate their time to the garden, because in the end, isn't that what it is all about?? So shout out to these boys when you see them and let them know what a good job you think they are doing! 

 Colin and Roman enjoying a job well done.

Colin and Roman enjoying a job well done.

Once it's complete we will be growing all sorts of food that will be fertilised by the silver perch that will live in the cycling tank!  Delicious! 

Our member Wendy Bishop came in one day to sketch the construction and plot in a potential path that will run behind the structure to allow better access to the crops...!  Her drawing is amazing! I am so jealous of her amazing artistic skill! A big thank you to Wendy for donating her time to creating this work of art for us.

 Drawing by Wendy Bishop

Drawing by Wendy Bishop

Keep your eye on the garden and watch it become more amazing everyday! So many exciting developments coming up!!