Alginate-based hydrogel substrates for the cultivation of Daucus carota in space agriculture

Kurzfassung

One major challenge of growing plants in space is transport, reuse, or disposal of the cultivation substrate after harvest. Therefore, developing substrates that are lightweight, enable healthy plant development and ensure low waste is essential for food production in space. This study evaluates two geometries, beads (Alg_AC_beads) and gels (Alg_AC_gel), of alginate hydrogel supplemented with activated carbon (AC) as substrates for carrot (Daucus carota subsp. sativus cv Caravel). Carrots were selected because of compatibility challenges with growing root crops in soilless culture systems and because they could provide astronaut crews with a menu option that many other vegetables lack: a crisp texture. The results highlight that alginate-based hydrogel preparation, morphology and degradation behavior strongly influence carrot growth. Over 21 days, the values of porosity and swelling rate for the Alg_AC_gel strongly diminished, inhibiting carrot development. The Alg_AC_beads allowed for better root aeration and carrot growth, but they did not show better dry weights compared to Alg_AC_gel. Further studies are recommended to further improve the alginate enriched with AC beads for root crops production and applications in space agriculture.