Seed Coating and Media Amendment Effects on Germination in Stinging Nettle (Urtica dioica L.).

Stinging nettle (Urtica dioica L.) is a promising alternative crop with a long history of usage. For centuries U. dioica has been harvested for food, fiber and medicine. The earliest studies on U. dioica agronomy were performed in the 1940’s with up to 500 ha planted in Austria and Germany.

One of the challenges in U. dioica agronomy is seed that is too small for direct seeding. In the current study, we examined the impact of seed coating on germination rates under lab and greenhouse conditions. Seed coating benefits small seeded species by improving germination and seedling establishment. Seed coating also leads to increased size and uniformity: qualities that necessary in mechanized planting systems where singulation and precise placement are critical. Seed coating materials can also be used to deliver protectants, nutrients, and safeners.

Seed germination in both coated and uncoated seeds was low: <50% in the greenhouse experiment and <15% in the lab trial. Seed coating did not improve germination potential and in the lab experiment actually depressed it. In the green house germination trial, seeding depth had greater impact on seed germination than media amendment with litter. Germination was highest in surface placed seed for both coated and uncoated seed. Amendment with litter was observed to depress germination in both coated and uncoated seed except in the uncoated treatment planted at 0.5 cm. seeding depth was also observed to have a negative impact on germination with the best performance being observed for surface placed seed (0 cm). The only exception was in uncoated seed in media amended with litter where germination was observed to increase with depth. In terms of germination rate, the trends were similar for both coated and uncoated seed relative to final tallies, with seeding depth having no significant effect on time to germination.