Hydroponics gardening can be turned on its head to produce the fantastic idea of vertical hydroponics. This is where instead of growing plants next to each other horizontally, they are grown above each other vertically (see Figure 1). Growing plants vertically has benefits in many situations, with the biggest benefit being the small footprint that is needed to prouduce a substantially-sized crop. This is the same philosophy of building multi-storey buildings where much more space can be used while using a much smaller area land. The reduced footprint size has great advantages for growing plants on balconies, in apartments or yards with limited space, as well as along walls and fences.
Hydroponics Systems Suitable for Vertical Hydroponics
Vertical hydroponics does introduce challenges that need to be considered. Not all of the hydroponics systems that are discussed on another page of this site are suitable for vertical hydroponics. Namely, water culture and ebb & flow systems can not be used in a vertical hydroponic garden as these systems require liquid to either be in contact with the plant roots constantly (in wature culture), or for the roots to be flooded periodically (in ebb & flow systems). Drip systems, and aeroponics systems on the other hand can be perfectly adapted to vertical hydroponic gardening (see Figure 1). If the nutrient film technique is used, the garden needs to be angled slightly so as to ensure that the nutrient solution always passes down the base of the vessel and contacts the roots.
Vertical hydronic gardens can be designed in two main fashions. Firstly, the growth containers can be stacked on top of one another in a twisted fashion, forming small openings at the corners of each container within which plants can be planted. Secondly, plants can be inserted into holes of a vertical cylinder. The second design type is shown in Figure 2.
Drip systems are more suited to stacked container designs, as a dripper can be installed at the base of each plant, providing a continuous supply of nutrients. After passing through the container holding the plant, the nutrients would pass to a central fluid collection reservoir and be passed back to the pump for recirculation. With the aeroponics design, which is shown in Figure 1, nutrients can be sprayed into the reservoir either through a single sprayer located at the top of the growing vessel, or ideally at regular intervals within the vessel. The sprayers should be positioned so that they spray horizontally to maximise their spraying area, and spaced at intervals that would ensure each plant is sprayed. In this way, plants can be located at a number of angles within the vessel, further increasing the yield of the garden. After being sprayed, nutrients fall to the bottom of the vessel and are passed out to a collection tube that passes the fluid to the main nutrient reservoir for recycling.
Requirements for Vertical Hydroponics
Vertical hydroponics gardens aren’t that different in design to horizontal hydroponics gardens. They need vessels to grow plants, most commonly pots that are staggered or PVC pipes, a nutrient reservoir, nutrient solution, drippers if using drip system hydroponcis or sprayers if using aeroponics, fluid lines, and a pump. Because of their increased height compared to “horizantal” hydroponic gardens, vertical hydroponics gardens need pumps that can deliver greater pressure, so as to be able to deliver nutrients to the top of the garden along with sufficient pressure to spray the nutrients onto the plants. When purchasing a pump for a vertical garden, be sure to check that it can provide sufficient pressure at the height that your garden will be. Vertical hydroponics gardens can also be grown indoors, where the light needs to be oriented in a way that ensures all plants are illuminated. This can be achieved by using smaller lights and even a mirror or light-reflecting foil (see Figure 2).
Vertical hydroponics provides an intelligent solution to gardeners that have limited horizontal space and for gardeners that want to maximise their yield. They are mostly suited to plants such as lettuce and herbs that don’t grow very tall, and can be used effectively on walls, fences, balconies, and for higher density growth in small yards.
Images are from (1) Roberto K. 2003, “How to hydroponics”, 4th edition, and (2) Ars Electronica.