For our balcony garden project, we have used commercially available plant pots / hydroponic systems, whenever possible. One planting system is a vertical hydroponic plant tower, another one a drip irrigation system for tomatoes, both we'll sell in our online-shop. To ensure the success of our balcony garden project, we have to use the balcony space as effective as possible. That's why we built a DIY NFT system for the balcony railings. For this we bought PVC-U rectangular and round pipes and glued them to long pipes with a glue, approved for drinking water applications. In these pipes we drilled holes for the net pots. The NFT balcony railings will later be integrated into the automatic nutrient solution irrigation system.
Perlite is of volcanic origin and highly porous. Perlite has advantages when growing from seeds, as it can be easily rinsed off from the roots. Plants grown in this way can also be easily converted into aeroponic systems (mist from nutrient solution), as the roots are completely free of substrate.
In our project we will place the carrots and radishes in a large tub filled with perlite, which is then flowed through with a time-controlled nutrient solution. The experiment is to show whether typical root vegetables can also be cultivated without soil in a kind of flood and drain system. The plan is to cultivate carrots, radishes, beetroot and spring onions in perlite. Let's see if it works.
It is early March 2019 - since we are aiming to grow 200 kg of vegetables and herbs on our own balcony, a small greenhouse was installed on the balcony in autumn 2018. It was built directly in front of a window so that it can be heated with the warm room air when the window is open.
This allows us to expose our young plants to natural light relatively early in the year, what is still best. Furthermore, the seedlings get better accustomed to the conditions outside due to the temperature fluctuations - as far as our theory goes.
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The plants in the planting tower are watered automatically. The planting column is a Deep Water System (DWC). At present the timer setting is adjusted so that the pump runs 15 minutes per hour, from 8 am to 8 pm. The nutrient solution is set to pH 5.9 and the conductivity to 1300 µS/cm. The adjustment / measurement is done by simple measuring instruments. Water temperature is 10-15 °C, which is not optimal, but still works quite well.
The seedlings in the trays get the same nutrient solution, but are watered manually. Some of the plants are later converted into so-called drip systems (re-circulating drip irrigation) more about this later.
We have added a schematic sketch of the function of the hydroponic plant tower. In simple terms, nutrient solution is pumped upwards by a pump and flows through the 3 plant levels back into the nutrient container, where a snorkel effect in the overflow pipes brings additional oxygen into the nutrient solution. A high oxygen supply is very important.
So far, the following has been planted:
Asia pick or pluck lettuce , Komatsuma, turnip greens, early lettuce, basil, strawberries, parsley, cauliflower, Chinese cabbage, savoy cabbage, babyleaf lettuce, pak choi, strawberry, rucola, romanesco, broccoli, lovage, tomato Berner, tomato Phantasia, yellow pepper, balcony tomato, cherry tomato, red pepper, eggplant, chilli.