The 2009 ASHS Annual Conference

A study was conducted to determine the influence of container design (Accelerator™ and black plastic containers) and MicroKote™ on the growth, nutrient uptake, and water loss from container-grown Ligustrum japonicum Thunb. ‘Recurvifolium’. Concern has been expressed by growers that plants produced in Accelerator™ containers dry out too fast and weeds grow from the openings on the sides of the container. MicroKote™ is a new micronutrient supplement that is painted on the inside wall of the container and contains Ca, Mg, Cu, Fe, Mn, and Zn. Plants were grown outdoors in full sun from May to Oct., 2008 on woven nursery groundcloth with a spacing of 90 cm on center. The substrate was an 8:1 blend of pine bark to sand with standard amendments. Plants were irrigated three times per day at 400 mL of water per irrigation using spray stakes so that water was not limiting. Treatments included a factorial combination of Accelerator™ containers (10.9 L) and standard black plastic squat containers (10.1 L) treated or not treated with MicroKote™. Container design had no influence on plant growth or final foliar nutrient concentrations. In July, water loss from plants growing in Accelerator™ containers was 69% greater than for plants in black plastic containers. Evaporation accounted for 65% for the water lost from Accelerator™ containers, compared to 35% for standard plastic containers. There was no difference in transpiration between types of containers in July. In September, total water loss was 23% greater for Accelerator™ containers compared to standard containers. Evaporation accounted for 53% of total water loss for the Accelerator™ containers compared to 22% for the standard containers. Transpiration accounted for 78% of water lost from standard containers in September compared to 47% for the Accelerator™ containers. Mean and maximum root zone temperatures from May to October were 27.8 °C and 45.0 °C for the Accelerator™ and 29.7 °C and 49.4 °C for the standard container, respectively. MicroKote™ had no influence on plant growth or final nutrient concentrations in the foliage. Weeds growing from holes in the sides of the Accelerator™ containers were not a problem in this study, though the author has seen problems in commercial nurseries. Under conditions of non-limiting water, plants grew just as well in both types of containers. Further work is warranted under conditions of limiting water during nursery production.