Here’s some amazing tech from Japan: Tokyo-based Mebiol is working on an membrane–based plant cultivation technology called Imec that makes it possible to let plants grow on thin film instead of soil. The film is made of a water-absorbent material called hydrogel and is just “tens of microns” thick.
Mebiol says that tomatoes, radish, cucumber, melons etc. need up to 80% less water to grow when compared with conventional culture and that 1g of SkyGel (that’s the brand name of the hydrogel) absorbs and holds 100ml of water. In contrast to soil, bacteria or viruses have no chance to harm the plants. Another advantage is that SkyGel can be used on various surfaces, including sand, concrete or ice (see this PDF for examples from recent years).
The film can be used to grow plants for 2-3 years before it needs to be replaced, according to the company.
This video, shot by Diginfonews in Tokyo, provides more insight (on both the advantages and the disadvantages of Imec):