A sowing unit including water-absorbing material, an enclosure and a seed, wherein the water-absorbing material includes a hygroscopic negatively-charged material capable of binding a positively charged nutrient ion selected from NH4+, L-arginine, L-lysine and L-histidine; and optionally a nutrient including a positively charged nutrient ion selected from K+, NH4+, L-arginine, L-lysine and L-histidine. Methods and uses of the sowing unit are described.