I am grateful to NPR for their recent piece in The Salt entitled Organic Farming Has A Plastic Problem. One Solution Is Controversial. It discusses the complexity of one of the norms of modern horticulture that is hard for us organic farmers to talk about: we cover the ground with plastic in order to grow your food using a system known as Plasticulture. We don't do this for all crops wherever possible, but we use it for many.
I remember as a child I had a book about Earth Day that taught me to reduce, reuse, recycle. I started to take these matters so seriously as an adolescent that I would deplore my mother every time she applied plastic wrap to a bowl of leftovers instead of using the Pyrex. I was shocked to learn during my first day as an organic farm apprentice that the real-world challenges of food production don't conform to the black-and-white perspectives I held as a child. Plastic mulch isn't in line with the ideals of the organic movement. And yet many organic farmers choose to use the stuff in order to have some insurance against unpredictable weather and save themselves and their crew back-breaking labor and its associated impact on profitability. This technology does have a lot of benefits, both economically to the farmer and, I would hypothesize, environmentally as well. HOW CAN THAT POSSIBLY BE?!? Allow me to explain.
1) You want tomatoes asap. And so do we! Raised beds covered in black plastic allow the soil to warm more quickly in the springtime so we can extend the season for warm-weather crops like tomatoes, cucumbers, and zucchini by a few weeks. We can also prepare beds for early spring planting late in the previous fall so that if we have a cool wet spring, our plantings aren't delayed by our inability to work the fields in March.
2) Weeds mean business. Without herbicides, organic farmers rely on mechanical cultivation to remove weeds from around plants and within planting rows. When the weather is favorable, this is a very effective means of controlling the weeds that compete for the water, nutrients, and sunlight your veggies need to grow. But as you've likely noticed in recent months, sometimes it rains a lot. And then rains some more. For days. During this time we are unable to get cultivation equipment into the field and the weeds quickly become unmanageable, choking out small direct-seeded crops like beets in no time. Attempting to cultivate the soil when the conditions aren't right can lead to soil compaction, plus any amount of soil disturbance can contribute to a loss of soil integrity and erosion. In other words, plasticulture may help protect soil under unfavorable conditions. Its improvements on crop yields due to weed control mean that more of the inputs we use result in harvestable product. High-yielding food crops that use fewer inputs per calorie produced are a good thing for both farmers and the environment.
3) Irrigation takes energy too. In addition to warming the soil and suppressing weed growth, the plastic helps to keep soil moisture close to the plants roots where they need it. Plants, especially during key growth phases such as when potatoes set tubers or onions begin to make bulbs, require very consistent levels of moisture to succeed. This means that if we aren't getting at least an inch of rain every week we are applying it through our irrigation system requiring electricity to pump water form a well. This pumping is energy and water-intensive and hot dry weather can quickly evaporate our efforts.
As the NPR piece explains, better products are being developed and tested but for now we farmers are left with the choice between using plastic mulch or forgoing these many benefits. With so many challenges to mid-size organic farming including skilled labor shortages, increased weather extremes, and a lack of efficient distribution networks, we make compromises and continue to do the best we can.
Thanks for reading! I welcome your thoughts and questions.