The Scoop On Plastics

There are three types of plastic pots that greenhouse growers typically use on a daily basis, according to Dr. Steven Cline of the Missouri Botanical Garden.

Polyethylene – The heavier plastic pots, including black wall pots used for nursery materials and larger greenhouse products.

Polypropylene – The lighter, medium-sized pots typically used for most of the other greenhouse products.

Polystyrene – Used for cell packs and trays.

According to Cline, recyclers cannot grind up all three plastic products together. Therefore, he encourages consumers, retailers and growers who participate in his program to at least sort out the polystyrene (cell packs and trays) from the other pots. This is an easy way to sort the pots in lieu of sorting by the numbering system on the bottom.

Also, Thomas Dudek of MSU Extension has a list of common plastic resins from greenhouses accepted by some recyclers.

Low density polyethylene (LDPE) – Used for greenhouse film and trickle irrigation tubing.

Linear low density polyethylene (LLDPE) – For stretch film for row covers.

Polyvinyl chloride (PVC) –Typically for rigid piping.

Polycarbonate (PC) – A clear, strong plastic sometimes used for greenhouse walls or roofing.

For Western Michigan growers, MSU Extension provides resources on recycling here .