Impact of Biopots on Plant Performance and Pot Degradation in Landscapes

Horticulture industry professionals and consumers are interested in biodegradable pots as alternatives to plastic pots given their perceived environmental sustainability. Research is underway investigating the impact of biopots on plant growth and development, durability of biopots for commercial production and shipping practices, and pot degradability after being planted in landscapes. This presentation reports first-year results on the impact of seven plantable biopots and one plastic pot on the performance of three ornamental species, Impatiens x 'Sunpatiens Compact Magenta', Cleome x 'Senorita Rosalita', Lantana x 'Luscious Citrus' in five landscape locations (IL, KY, MS, WV, and TX) and the degradation of these biopots at the end of the growing season. The seven biopots were Jiffy pot (peat moss), SoilWrap (bio-polymer), Fertilpot (wood pulp), coir (coconut fiber), Cowpot (composted cow manure), NetPot (slotted pressed rice hulls), and straw pot (rice straw). As a comparison, 4-in plastic pot was included. Rooted cuttings of the above plants were potted into these eight types of pots and grown in the greenhouses at five locations until marketable sizes before being transplanted to respective landscapes. The experiment was a completely randomized design with three replications and three subsamples. Due to differences in climate conditions among different locations, the experiments were terminated in each location when the growing degree day reached to 4630 with a base temperature of 40 °F. Upon termination, shoot dry weight was determined after oven dried. All pots were dug out, cleaned, rated visually, and dried in the oven. The degradation percentage was determined by comparing the dry weight of the dug pots with the dry weight of the new pots. Results from El Paso, TX, indicated that plant species did not affect the pot degradation. The degradation percentages of the seven biopots at the end of the growing season were 92%, 82%, 66%, 50%, 49%, 39%, and 5% for SoilWrap, Cowpot, Fertilpot, Jiffy pot, straw pot, coir, and NetPot, respectively. The impact of pot type on plant growth varied with time. Based on the bi-weekly measurement of plant growth index, plants in SoilWrap grew better, followed by NetPot and Jiffy pot, and plastic pots produced smallest plants. However, the effect of pot type diminished as plants grew. The final shoot dry weight of lantana was greatest in SoilWrap and smallest in plastic pots, but no differences were found among other pot types.