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Quality over Quantity – Growing Nutrient Dense Food in Urban Gardens


By Kat Gawlik,

If we are to grow and produce enough food to meet our families’ nutritional needs in an urban situation, we need to go beyond organic, to remineralise the soil where there are deficiencies, cultivate soils rich with microbes and to grow food that is nutrient dense.

The Koanga Institute’s 200sqm Urban Garden Project’s aim is to showcase how people living in small urban sections can satisfy their nutritional needs following a Weston Price diet; that is whole unprocessed foods including eggs and meat from rabbits and guinea pigs. The project garden located at the Koanga Institute in Wairoa, New Zealand includes 40sqm of bio-intensive gardens, a top bar beehive, rabbits over a worm farm, a chicken scratch yard which is where all the compost is made, a passive solar cloche incorporating water drums as thermal mass, guinea pig tractor, a forest garden area with 34 different heritage fruit/nut trees, bushes and vines planted with understory and nitrogen fixing plants, soldier fly farm and water-wise wicking beds. The garden was designed during a Permaculture Design Certificate at the Koanga Institute a few years ago and has been flourishing for 16 months now. See previous blog posts for further background information.


The Urban Garden project is ‘not just a pretty and functional garden’. It is a research garden where the soil is tested, inputs and outputs are recorded, nutrient levels of the foods are tested using a refractometer, and a monetary value is put on what is harvested showing the economic viability and savings that could be made by people with a similar setup. Last month, $793 worth of food was produced in the urban garden, and that is just the beginning. Once the fruit trees start producing, it will be a different story.

There is a focus on growing nutrient dense food because in an urban situation where we have minimal space the emphasis is on quality not quantity. At Koanga Institute, they are very focused on adding minerals from seaweed, animal bones, phosphorus accumulators such as lupins and oats, garden lime, liquid iodine and pre-mixed cocktails of minerals such as EF Nature’s Garden from Environmental Fertilisers into the compost to add to the calcium and phosphorus deficient soils in NZ.


An Essential Tool- The Refractometer

A refractometer measures the sugar, mineral and protein levels in plant material and reflects nutrient level and pest/disease resistance in the plant. Extract the sap from the plant using a garlic crusher and add a few drops to the glass before covering it. Hold it up to the light to see the brix reading.


The refractometer measures the amount of light that is refracted or bent, which reflects the amount of water and dissolved solids in the sap/liquid.

Below a brix reading of 12, the soil needs some work, anything over 12 is considered to be nutritionally dense, and of high quality- fit for human consumption! A recent test at Koanga Institute revealed the hulless oat which is grown for eating and also to add to compost as a highly ligneous carbon additive, had a brix level of 22! This is great as the minerals and nutrients will be recycled through the compost pile and eventually given back to the plants.

Watch the video below to see how a refractometer was used to test the brix levels of chinese cabbage harvested from the wicking beds in the 200sqm Urban Garden.

Kay Baxter Tests Nutrient Density from a Wicking Bed in the 200sqm Urban Garden

Try using a refractometer to test the quality of food bought from the supermarket and compare it to your own home grown food. It is also a good tool to measure the effectiveness of any fertilising regimes. The best time to test is at least a couple of hours after the sun has hit the leaves in the morning, and usually the brix levels may change at night when the sugars in the leaves are more concentrated in the roots. They can be bought from Koanga Institute in NZ, or from the PRI shop in Australia.


The Koanga Institute currently has a crowd-funding campaign on Indiegogo to raise funds to keep maintaining and testing the techniques in the 200sqm Urban Garden, and to further develop it to include a council-approved legal composting toilet, passive solar food dryer, permanent wicking beds, aquaponics, and to convert a concreted area into a plethora of horizontal and vertical food growing systems. We want our urban garden to be an example for the rest of the world of how we can be food secure and nutritionally resilient in cities and urban areas.

Please help us reach our target by contributing to our crowd-funder (get ebooks, seeds and perks in return!) and following Koanga’s 200sqm Urban Garden Project to see how you too can replicate a productive system in an urban situation that grows healthy plants, animals and people!



  1. I think a primal/paleo diet is better for Permaculture because you can save the small amount of grain you grow as back up or supplement feed for the animals. Plus, there is no evidence to suggest humans had eaten grains prior to 12,000BC

    1. Even though people may not have eaten grains before 12,0000BC, that doesn’t mean it shouldn’t be eaten. As we evolve so does our diet, and I think that is important to keep in mind. Grain is a staple crop that has supplemented our diet for a very long time

    2. In an urban garden situation when space is limited, grain is not efficient to grow. You are better off growing potatoes or root crops that you get more return from a small space. In Koanga Institute’s urban garden they are experimenting with growing potatoes vertically in wooden frames that are added to creating a ‘wall’, and they are finding not all of NZ’s heritage varieties of potatoes are suited to that style of growing.

      1. Indeed root crops like potatoes allow better caloric density in an urban garden. But they are also significantly lower in protein than grains. 100g of potato has 2g of protein, while 100g of wheat, maize,millet, or oats have over 9g of protein. Given how cheap grains are from the grocer, however, it does make little sense to grow them in the typical urban garden compared to fresh fruit and vegetables, which are much more expensive from a grocer.

        1. Currently in the Koanga Urban Garden, most protein derived is through chicken eggs (daily) and meat from the rabbits and guinea pigs (not so regularly). Once the nut trees are producing that is another source, along with beans and corn etc when harvested.

  2. We have little evidence of what *anybody* ate prior to 12,000 BC. What we do know is that Native Americans were breeding and eating maize (corn) shortly after arriving on American shores, we know that because processing maize into meal results in slicks or cups on rocks where it is ground. But for grains that don’t require such processing, we have no easy evidence of their consumption — or non-consumption, for that matter. Lack of evidence is not evidence of lack. Just sayin’.

  3. Quality is a unit less measure. In reality, we need to strive for nutrient density when planning use of space. In some places, nutrient value is equated with cash cost, but as we have been mixing diets between cultures and places as long as we have practiced migration, there is no true “cultural” diet.

    We can and must produce so we harvest the most of our natural inputs (sunlight, rainfall, carbon/ nitrogen/ oxygen from the air) while encouraging natural cycles to continue. Within this, we also need to remember that nature moves nutrients through and across spaces (places) so it is not entirely unnatural to bring in small amounts to manage and promote well balanced conditions.

    It is when we assume that dollars = nutrients and that nature will process and provide at whatever level our extraction and addition is that we fall into an imbalance. This imbalance costs all systems.

  4. Agreed Ed, Nutrient balance and density should be considered across the biota – not just feeding the humans/human influenced animals.

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