Investigation of Konjac Glucomannan seed tapes for vertical farming and riverbank revegetation

Seed tapes made from water-soluble biopolymers can be used to secure plant seeds in specific locations or to plant them in the soil. Konjac glucomannan, also called konjac gum, is a biopolymer with a high water-holding capacity. It is a polysaccharide extracted from the ground tuber of plants belonging to the genus Amorphophallus.

Commercially available seed tapes usually consist of two layers of cellulose and typically dissolve in the soil within 4-8 weeks. This timeframe is significantly longer than what is required for vertical farming experiments using textile substrates, where the seeds typically need to be secured for about 1-2 weeks until they have developed enough roots to anchor themselves in the textile. Even when using seed tapes in the soil – for example, for riverbank revegetation – it is not necessarily essential for the seed tape to take a long time to dissolve.

Therefore, a project was conducted to investigate the potential use of konjac glucomannan seed tapes in vertical farming applications and along waterways. First, konjac glucomannan films of various thicknesses were produced from solutions with different polymer concentrations and optimized until the films were stable enough to be handled. The optimized konjac glucomannan seed tapes, containing various types of seeds, were incorporated into double-layer knitted fabrics, which were used in vertical farming trials, and also tested in soil. The decomposition times of the seed tapes were measured.

Konjac glucomannan seed tapes did not prove effective in vertical farming, as the irrigation was insufficient to dissolve the material during 21 days, and the seeds did not germinate. However, they completely dissolved in the riverbank revegetation trials within 7 days, and the plant seeds were able to germinate, develop roots, and subsequently grow normally, as expected. These trials demonstrate that konjac glucomannan seed tapes are suitable for riverbank revegetation.