Hydro-gel is a super absorbent polymer that has been used in horticulture since the 1970’s and more recently became an established component of certain hydroponic products.
Noteworthy characteristics of Hydro-gel include an ability to absorb several hundred times its own weight of liquid and a predictable slow releasing of any absorbed liquid. The granules will also absorb nutrient solution, again releasing this gradually over a long period of time. Once the granules start to show signs of releasing the liquid, they can easily be replenished by simply adding more liquid.
Many everyday products contain Hydro-gel, like Ona Gel for example, but in horticulture it’s most often used with decorative plants – the types stocked by supermarkets featuring a clear vase and coloured gel as the medium. Hydro-gel also appears in several other areas, from providing moisture when transplanting trees to being used as a soil enhancer, aiding water retention, and turning previously barren areas into places where plants can grow.
Another unique quality of Hydro-gel is that it will accommodate plants when used with saline water right up to the strength of seawater. Bearing in mind fresh water supplies are limited for some parts of the world, any opportunity to reduce agricultural demands on dwindling supplies should be explored.
Hydro-gel is also being heralded as the potential solution to space mission hydroponics. Due to the small amount of space required for transport and the efficient use of water, it represents a very strong candidate.
Currently the use of Hydro-gel as the sole medium really only proves effective for seedlings and plants with a lot of green growth. The limited amount of moisture released by the Hydro-gel does not at present meet the requirements of heavily fruiting plants.
Whilst this restriction currently makes Hydro-gel unsuitable for commercial projects, it also happens to be one of the mediums’ biggest assets. A series of studies actually suggest that the product could help reduce the amount of water used in agriculture by over 50%! Furthermore, Hydro-gel is also very easy to clean and re-use. These ecological benefits of Hydro-gel are perhaps the driving force behind continuing research and development. On the reverse side of the ecological debate, the polymer has plastic components and takes a long time to biodegrade in landfill site.
A recent development in Japan has seen plants grow from a special ultra thin film of hydro-gel. By significantly reducing the amount of hydro-gel used, many of the previously encountered problems were avoided. The film looks a little bit like the spreader mat used in nft systems, but instead of merely carrying the solution, it acts as the media and allows roots to establish. The scientists have successfully grown spinach, tomatoes and even melons using the film. Although only small plants managed to emerge from the testing process, the fact that they grew on the film and produced fruits raises hope for further and more significant breakthroughs in the future.
Clearly there are big plans in store for this dynamic product, and if all goes to plan, it could go on to trigger a revolution in hydroponic growth!