Recycled Waste Paper as a Non-chemical Alternative for Weed Control in Container Production

Studies were conducted to evaluate recycled waste paper mulch as a means of controlling weeds in the production of container-grown crops. Two forms of recycled waste paper products were evaluated—pelletized and crumbled. Both were tested at two depths, 12.5 mm (0.5 in) and 25 mm (1 in). A fabric disk and a fabric disk treated with Spin Out were also evaluated. With both the recycled waste paper mulch treatments and the fabric disk treatments, spurge seed were sown either under or on top of the treatment. Recycled waste paper pellets applied to a depth of 25 mm (1 in) suppressed spurge germination, regardless of whether spurge seed were sown on top of the mulch or under the mulch. Recycled crumble provided poor spurge control at both depths, and there was increased spurge growth when spurge were sown on top of the mulch compared to when the seed were sown under the crumble mulch. Pellets at the 25 mm (1 in) depth, provided weed control equal to that of Rout (oxyfluorfen + oryzalin) herbicide. Results from the fabric disks showed limited spurge control was obtained with any treatment. Fabric disks allowed weed growth around the container circumference and in the area where the disk fits around the plant. Both cultivars of azaleas grown with recycled waste paper mulch were generally similar in size to non-treated control plants and Rout treated plants at 240 DAT (days after treatment). At 550 DAT plant growth was similar among all treatments except ‘Fashion’ azalea had smaller growth indices when grown with pellets compared to those grown with crumble. Container medium solution pH and electrical conductivity (soluble salts) were within the recommended range for acceptable plant growth. Research suggests that pellets applied at 25 mm (1 in) should provide effective non-chemical weed control resulting in less herbicide use and/or fewer hours of labor for weeding.