Lining a 4 ft high raised garden ... size 8X4X4

Asked May 26, 2020, 3:25 PM EDT

My 88 year old husband has built me a 4 ft.raised garden using steel stakes , coated wire, and lining it with 3ml plastic sheeting we bought at Lowes. My daughter and son in law came by briefly and said I can't grow vegetables in this because the plastic is not save, like water bottles are. I am upset, and can not tell my husband this as he has worked so hard making this happen. Are there any options? I hope so....

Bernalillo County New Mexico

1 Response

Thank you for your question. I have surveyed Extension articles from half of the states, and every single one recommends using 3ml black plastic to line raised beds. In fact, you are far more at risk for using treated wood than plastic liners: https://www.extension.iastate.edu/smallfarms/toxicity-concerns-about-raised-bed-construction-materials

he three plastics used to make bottles (PET, HDPE, and LDPE) are considered to be safe, and safe enough they can be recycled. (https://www2.illinois.gov/cms/agency/recycling/i-cycle/Pages/plastics.aspx) Lowe's 3 ml plastic is also polyethylene (https://www.lowes.com/pd/BARRICADE-10-ft-x-25-ft-Clear-3-mil-Plastic-Sheeting/1000158123

The other difference which makes this sheeting safe is the mediation of soil microbes in your raised garden bed. There are some microbes that are able to degrade ("eat") the chemicals given off by plastic, so it does not reach plant roots. And, in order for the chemicals to reach them, the chemical has to move laterally, which is not how water works. I suggest you place non-edible plants such as nasturtiums (which also act as trap plants for aphids) around the outside of the planter, with edibles further away from the liner. Hope this helps keep family peace--and health. Good luck!