Hydroponic farming, although known since the times of Babylon, still raises a lot of controversy, myths, and misconceptions. This is especially evident in the context of vertical farming. In this text, we will dispel some of the myths and present the benefits and potential that comes with using this cultivation method.
Hydroponic farming is a method of growing plants that has existed since the time of Babylon. It may come to you as a surprise that The Hanging Gardens of Semiramis served as a prototype for today’s hydroponic systems. Their intricate layout consisted of seven separate terraces. To avoid flooding or overflow, the roof of each level was covered with tar and a lead coating. The outer edges of the terraces were covered with climbing plants, which descended towards the lower terraces, creating a green and steep mountain with trees, hedges, bushes and flowers. It looked as if the gardens were floating in the air, hence they are referred to as hanging gardens. Water from the Euphrates River was used to irrigate the gardens. It was delivered to different levels using a system built in of channels and drains.
Hydroponic farming is soilless plant cultivation carried out in appropriate substrates or even without them. These are so-called organic or inert substrates used to stabilize the plant. They do not contain any nutrients and are easily permeable to aqueous solutions.
Plant roots have continuous access to macro- (nitrogen, phosphorus, potassium, magnesium, calcium, sulfur) and micronutrients (iron, chlorine, copper, zinc, boron, molybdenum, manganese, nickel) dissolved in water (nutrient solution). The amount of micro and macro elements depends on the cultivated plant species and whether the aim is, for example, faster plant growth, flowering or fruit setting.
Hydroponics is mainly used in greenhouse vegetable, herb, and ornamental plant cultivation, as well as in vertical farming. It is worth noting that hydroponic plant cultivation can be done both indoors and outdoors, e.g., in a garden. However, it is more often talked about in the context of indoor cultivation of plants, as hydroponic can be an alternative to traditional farming methods.
Vertical farming in a hydroponic system is a technology that allows for independence from external climatic and atmospheric conditions. We already know that this modern farming method will be important for ensuring food security in the future. Research on it is conducted by private companies as well as public institutions. NASA scientists are conducting experiments on crops grown in controlled conditions using hydroponic, aeroponic, and aquaponic farming techniques.
In the era of increasing concern for the natural environment, a positive trend in reducing the use of chemical pesticides is observed across the European Union. According to the data of the European Commission, the risk related to the use of chemical pesticides in agriculture shows a steady decrease: by 14% compared to the reference period 2015-2017 and by 1% compared to 2019.
This positive information shows that farmers are increasingly conscious and responsible about the use of pesticides, which translates into an improvement in the condition of the natural environment and consumer health. In the context of these activities, it is worth noting that in 2022 Poland used an average of 2.1 kg of plant protection products per hectare, which is lower than the EU average of 3.1 kg/ha.
Many people associate hydroponics with the use of synthetic substances, which can lead to concerns about the quality of the plants produced. However, in vertical farming, hydroponics is used with significantly less fertilizer – up to 65% less! There is no need to use plant protection products, because these are isolated crops, which, when properly functioning, do not have “access” to weeds, insects, fungi or viruses.
It is important to note that all plants, regardless of their origin, undergo quality control before they are sold. Vegetable and fruit producers have a legal obligation to send their products to accredited laboratories to ensure they are safe for consumption. This process is controlled by national and EU laws, regulations, and other legal documents. As a result, consumers can rest assured that the fruits and vegetables they purchase have passed rigorous safety standards and are fit for consumption.
As part of its R&D activities, Hydropolis has multiple vertical farming operations and conducts studies of the plant’s microbiological composition. In 2021, the company conducted tests on Lollo Bionda lettuce and found impressive results. According to the guidelines contained in the European Commission’s regulation, one kilogram of fresh lettuce grown in a greenhouse cannot have more than 4500 mg NO3 per kg during the collection period from October 1 to March 31 1. The results showed that the vertically grown lettuce had 10 times fewer nitrates than the mandatory limit, demonstrating the high quality of Hydropolis’s vertical farming practices.
| Source | Nitrates mg NO3/kg FW |
| UE | Maximum permitted levels (mg NO3/kg):Harvested from October 1 to March 31: greenhouse lettuce4500 |
| Hydropolis | Amount: 449,193 |
Vertical farming requires about one-third less space than traditional agriculture to produce the same number of herbs or lettuce. Over 720 hours on a 12-hectare area, the same amount of food is produced as in traditional farming on 50 hectares for 365 days.
In 2019, the global market value of vertical agricultural products was estimated at USD 1.02 billion. It is expected to grow at a compound annual growth rate (CAGR) of 25.7% from 2020 to 2027.
Vertical farming is an integral part of modern agriculture, which aims at the sustainable use of resources: both land and water. The efficiency of land, water, CO2, and light energy utilization in vertical farming can be up to 100, 40, 2, and 1.7 times higher, respectively, than in greenhouses2.
With the right conditions in hydroponic vertical farming, plants grow faster and are more resistant to diseases (compared to traditional agriculture). This allows for increased yields and improved quality of food production.
1 COMMISSION REGULATION (EC) No 1881/2006 of December 19, 2006 setting maximum levels for certain contaminants in foodstuffs (Text with EOG relevance).
2 HORTSCIENCE 53(4):496–503, Responses of Sweet Basil to Different Daily Light Integrals in Photosynthesis, Morphology, Yield, and Nutritional Quality, 2018.
