Organic Production of Sunflowers in High Tunnels

This study evaluated the organic production of sunflower cut flowers in high tunnels. Cover crops were grown over the winter and incorporated into the soil in the following spring and subsequently sunflower plants (Infrared Mix F₁) were grown in the high tunnels. There were four cover crop treatments: Annual ryegrass (Lolium multiflorum Lam.) (75 lbs/acre), Annual ryegrass (50 lbs/acre) + hairy vetch (Vicia villosa) (31 lbs/acre), Caliente 199 mustard blend (Brassica juncea + Sinapis alba) (10 lbs/acre), and no cover crop (control). Results showed that in general, sunflower plants grown in the no cover crop plot were taller than plants grown in the cover crop plots, especially earlier in the season. However, the total number of cut stems was similar among all treatments, with plants grown in mustard plot produced slightly less stems. The soil analysis data showed that prior to tilling the cover crops, soil nitrate concentrations in the top 20 cm were higher in the no cover crop plot than in the cover crop plots. Further studies will be conducted to look at the long-term effects of cover crops on soil properties and crop production in high tunnels.