How many vegetables and herbs can be produced in a small space in an urban environment in a calendar year?
The climate is changing and pollution of the air, soil and sea is increasing. Our self-experiment aims to produce fresh food, such as vegetables and herbs, for our own consumption in a self-controlled way. This allows us to enjoy fresher and healthier food and produces less packaging waste. In addition, with our self-supplying balcony garden, we are trying to save water through hydropponic cultivation and to do completely without herbicides and pesticides.
With this report we want to summarize and publish all our experiences in one place.
We summarize how much and what we have grown hydroponically. This also includes the consumption of electricity, fertiliser and water. We will go deeper into what has worked well and what has worked less well. We report on how we have changed ourselves and our purchasing behaviour during this time.
Our principles are "A garden for those without a garden" and "Do it for yourself and the environment".
Be curious what kind of results we will present.
Throughout 2019, from April to November, we harvested a total of 135 kg of vegetables, salads and herbs.
The effective cultivation area on our 2 balconies was 6.5 m². This means that our plants have taken up 6.5 m². But as you can see in the blog posts, there was still enough free space left to use the balconies as usual. But we did not quite reach our goal of 200 kg.
Why 200 kg? We had read that every person should eat about 100 kg of vegetables, salads etc. per year. This is how the figure of 200 kg for two people came about. What we had not taken into account in our euphoria was that we did not grow apples or root vegetables, for example, i.e. anything that had the right weight. Harvesting 200 kg in 6 months main harvest time - so we misjudged.
You would have to harvest "every day" about 1.1 kg. Who can process / eat 1.1 kg of vegetables, herbs, salads every day?
In order to demonstrate how the quantity relates to the weight, we took photos and published them in our July report. When we talk about 200 kg today we know better what this amount of vegetable is. But nevertheless we have miscalculated.
Despite this we are very satisfied with our result of 135 kg. Since we are not vegatarians, what we harvested was more than enough for 2 persons. In the harvest peak phase we had even provided grateful neighbours and friends with salads, peppers, cucumbers, tomatoes etc. - as we had overproduction that we could no longer cope with. From September on we also did not fill all the planting holes anymore, because it was simply too much for us.
The only vegetables we bought were potatoes, carrots, onions and other root vegetables and of course apples or pears.
First of all - a certain interest and commitment for such a self-sustaining project should be present. Whether for ecological or nutritional reasons, or whatever.
Our main reasons were:
I would like to do something for me, namely to eat fresh and healthy food and do it in an ecologically sensible way. In addition, cultivation should be feasible for us.
Feasible means that we do not have a garden, but two balconies. We are both in business, so we only have limited time. We travel a lot, both privately and on business, but it had to work out anyway. So the hydroponics cultivation was the ideal solution for us.
We chose the automated, hydroponic cultivation. All plant containers were supplied via a central water/nutrient tank. Individual plant pots, e.g. the vertical plant columns, were additionally supplied by small water pumps controlled by a timer. The complete system was automated via timers in such a way that we could leave the plants to themselves for about 10 days if necessary (vacation).
It was a real effort to ensure there were always enough young plants - after all, we had 320 planting holes. The challenge here was to plan when what was ripe for harvesting and when these plants needed to be replaced by new ones. Here we had our timing problems. The beautiful word biodiversity gets a new meaning when you have had too much of one and too little of another. But next year will be better for sure.
Ongoing maintenance was essentially limited to measuring the EC and pH values using a hand-held meter and adjusting by fertilizing or lowering the pH value. Of course, the plants had to be cut out or tied, as is the case with plants.
We were mostly protected from pests. Only the cabbage butterfly gave us some trouble. But we simply let him do his job. We had aphids very rarely, at the beginning with Asian salads. Due to their filigree structure they are predestined for aphids. Pesticides were never used.
It may sound overstated, but at the peak of the harvest season July / August, we were most involved with the harvesting and, in connection with this, the timely utilization of the yield. So if you don't like cooking, you should keep your hands off such projects. Because everyone who grows plants will avoid throwing away one leaf too many. We have learnt again - to know how much effort it takes to grow food. We now have even more respect for food. Things that you lose sight of when supermarkets are always full.
Everything worked well, in 7 months of operation we had only 2 major failures. Once a supply hose for the upper balcony was pulled out through a pumpkin that had grown over the hose. The other time a pipe in a plant column was blocked by too much root growth. In both cases the problem was noticed in time so that no plant losses occurred.
There are many DIY building instructions always Internet on the subject of hydroponics planting systems. Cheaper is always possible. Since we wanted to make hydroponics cultivation and our shop www.küchenfrisch.de more known with our blog, we used as many products as possible that are available for purchase at our shop. We wanted to show what works and how it works to create trust in our products.
Only with the planting systems that we ourselves did not yet have on offer, we resorted to the DIY method. One example is the NFT balcony railing, the modified Deep Water containers or our DWC planters with trellis. We have always made sure that all the hardware we use is free of harmful substances such as plasticizers. To be sure that we did everything correctly, samples were sent to a food laboratory for analysis. Result: No plasticizers could be detected (see taste and analysis below).
It was also important for us (especially for my wife) that what belongs to the hydroponic planting system visually fits into the given ambience and that the balconies could still fulfil their original purpose of being an oasis of well-being.
The following were used in our project
3 planting columns (124 planting holes)
2 Wilma Drip Systems (16 plant pots)
3 DWC - Deep Water Planters modified - (37 planting holes)
2 planters boxes with trellis equipped with DWC (20 planting holes)
2 NFT wall systems (70 planting holes)
2 NFT DIY balcony railing systems (54 planting holes)
1 planter modified to the Drip System
1 central reservoir
Various small parts such as timers, hoses, fixing material ....
Total space for 320 plants
The one-off investment costs for 320 planting holes were between 1500 - 1800 euros. Since the hydroponics system can be used anew every year, the costs are relativized. With the experience we have gained, 240 planting holes are probably sufficient for 2 persons and our requirements are completely sufficient.
For our balcony garden project it was of course also important to record which running costs are incurred. We determined the amount of water using a water meter and calculated the electricity consumption based on the specified wattage and running time. We documented the added fertilizer and the pH-agent for pH-regulation at each addition and added it at the end of the project.
The table shows the various consumption values, in total 225 EUR for 7 months of comfortable gardening and harvesting of a good 135 kg of delicious, varied greenery.
We have compared the consumption of water with the garden of my parents again, as already done in July in the blog - the saving of about 75% water has been confirmed. Terrific!
During the 7 months my parents needed about 25 m³ water - we only needed 6.2 m³. Because we wanted to have everything under control this year we deliberately did not use rainwater, but this can be changed in the future.
For fertilizer we only added about 70% of the recommended amount. We have not intentionally reduced the amount of fertilizer but kept the maintenance effort low and only measured and added fertilizer about every 14 days. Nevertheless, everything has grown super, further optimizations are still possible. Not included are the seeds and substrate material used.
Unfortunately, there are still sometimes reservations that hydroponic cultivation is "unnatural" and that the herbs, salads and vegetables do not taste as good as when grown in soil. We have tried not to be biased in our taste evaluation and have also asked many test eaters from our acquaintance for their opinion.
Conclusion: The taste of hydroponically grown herbs, salads and vegetables is very good, even more intense.
Analysis of tomatoes and nutrient solution for plastic components
The second much discussed topic is plasticisers from plastics in food. In setting up the system, we have taken care to use only plastics that are used in the food sector. In our case these are PP, PE, ABS and rigid PVC (PVC-U).
Nevertheless, we have had our tomatoes, which have a longer growing period, and the nutrient solution tested by an analytical laboratory for "plasticizers in food". The samples were tested for 25 plasticizers with the result that NO plasticizers could be detected. Even though we expected this, we are pleased with this confirmation. Unfortunately we are not allowed to publish the test report.
That worked well:
That did not work optimally:
This should be taken into account:
Our expectations have been fully met. We were surprised how well and without problems everything worked out. The effort after the whole system was up and running is really not comparable with the effort that is required in a garden. We didn't have to water every day, and with snails or pest infestation we had almost no work. Most of the work in a positive sense was harvesting and processing the crop. We can only wonder that hydroponic cultivation is not better known in Germany. Even for people who have a garden, hydroponic cultivation makes sense - to save resources and reduce work.
In addition, our shopping and eating habits have changed considerably. Our purchases have been reduced considerably, we have eaten many more salads and vegetables and cooked in a more varied way. A great experience!
Of course there are people who say that hydroponics is unnatural - which is partly true. But is the cultivation of crops on fields so natural when you look at all the monocultures - these were also artificially created by humans - or have you ever seen a single variety of vegetable field that planted itself? Just because it is not grown in soil but in water does not mean that it is perseveringly more unnatural. There are also many plants that grow in water, like algae, water lilies, rice or watercress.
In this sense we hope that we could show and explain the hydroponic cultivation to you, so that everyone can form his own opinion.