Research has shown that a problem in pot-in-pot (PIP) production systems has been the growth of roots out of the planted container, through holes in the holder pot and into the surrounding soil. A study was conducted with Lagerstroemia indica x fauriei ‘Acoma’ to evaluate methods for reducing rooting-out problems in a PIP production system. The products tested were Biobarrier™, a geotextile fabric impregnated with trifluralin; Root Control™ fabric bag material; and Spin Out™, a commercial formulation of copper hydroxide (7.1%) in latex paint. Biobarrier™ reduced plant height, shoot dry weight, percent root dry weight outside of the planted container and total biomass compared to the non-treated control. For the control, 7.1% of the total root dry weight was found between the holder pot and planted container compared to 0.2% for the Biobarrier™ treatment. When the holder pot and planted container or the planted container and Root Control™ fabric were both treated with Spin Out™, plant height and shoot dry weight were reduced. Spin Out™ reduced root circling on the sidewalls of the planted containers but not on the bottom of the containers. All treatments except the control reduced rooting-out to a degree which allowed for the manual harvesting of the planted container from the holder pot after seven months in the field.
Technical assistance of Bruce Tucker, financial assistance of Griffin Corporation, Valdosta, GA, statistical assistance of Ben Mullinix and donation of plant material by Wight Nurseries, Cairo, GA, Biobarrier™ by Reemay, Inc., Old Hickory, TN and Root Control™ fabric by Root Control, Inc., Oklahoma City, OK is acknowledged and gratefully appreciated.