Large Scale Recycling of Used Potting Media with Solarization

Project Overview

Project Type: On-Farm Research
Funds awarded in 2013: $3,161.00
Projected End Date: 12/31/2015
Region: Southern
State: Florida
Principal Investigator:
Shawn Steed
UF/IFAS Extension

Annual Reports


  • Additional Plants: native plants, ornamentals


  • Education and Training: extension, on-farm/ranch research
  • Energy: solar energy
  • Pest Management: soil solarization
  • Soil Management: organic matter, soil analysis

    Proposal abstract:

    This project will research the viability of recycling old potting media from dumped container plants using solarization. Currently old container potting media is usually dumped in piles in a back fringe of the nursery leaching remaining fertilizer into the surrounding areas. Some nurseries have found ways to deal with this issue by incorporating the old media with a percentage of new mix. The majority of nursery producers do not reuse their old potting media. This is from fear of contamination of new media with pathogens, nematode infestations and weed seeds that will reduce quality and add costs to production. Soil physical properties may change with the breakdown of bark and decomposition of peat and may also adversely affect new potting media. In recent years there have been issues with availability of peat and pine bark. Sustainability of peat is a debatable question and composted pine bark availability has fluctuated due to demand in energy producing feedstocks. Old potting media represents a major opportunity in the overall sustainability of the nursery industry. This resource that is currently a problematic waste might possibly be reused as a component of container media for freshly potted plants if a low cost, large scale, easily managed solution could be developed with potential drawbacks (ie. weeds, nematodes, pathogens) analyzed and accounted for.

    Project objectives from proposal:

    To determine viability of solarization of old potting media.

    We will look at two different methods using a similar approach, only the scale will differ. We will solarize used potting media with clear poly and determine if the results (temperatures and treatment) are satisfactory to growers in terms of pest counts and physical attributes of the processed media.

    We will also recycle this material in different ratios with fresh potting soil to determine if there is suitability in growing woody ornamental plants.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.