Fresh, abundant fruit and vegetables in year round supply are what most residents of the modern mega-cities of Japan have come to expect. People rarely stop to consider exactly how any of the fresh produce got there, let alone giving extra thought to how it is grown during peak Winter seasons.
In reality however, the cold temperatures and conditions in rural Japan in Winter dictate a major difference in how vegetables need to be grown in the off season. While Summer sees various farming techniques that protect crops from persistent heat, insects and high humidity, Winter farming calls for warmth and protection from bitterly cold winds, frost and snow. As such, when the growing days become shorter, farmers all across Japan turn to plastic … And mountains of it!
Frost protection tunnels for lettuce are a common sight in the agricultural areas of Japan in Winter. Preparing and planting the tunnels with seedlings is a labor intensive activity. Specialized machines are used to both mound the soil into raised rows as well as to stretch black plastic over the leveled mounds. This aids heat capture and prevents weed growth as the seedlings develop. The plastic liner is pre-cut with staggered holes positioned abreast for placement of the individual plants. The liner has the edges automatically tucked neatly under the soil to secure it in place.
Directly after planting, half hoops of metal rod are then pushed into the soft soil to form a tunnel structure above the black plastic. A further sheet of strong, clear plastic is laid over the the top of the structure to form an enclosed tunnel. Finally, the tunnel plastic is strapped to the metal hoops to provide a tight cover and aerodynamic structure that can withstand strong Winter winds and snow. The soil mounds and seedlings are now protected and ready for Winter growth.
The plastic tunnels are only a meter or so in width and are spaced so farmers can walk between them for servicing requirements. Later in the Winter season as temperatures begin rise and the risks of frost withdraws, the lower edges of the tunnels can be opened to allow better aeration and to give access for spraying, inspection or any other treatment required.
While plots of land for growing vegetables in Japan tend to be relatively small individually, the cumulative sight of numerous neighboring plots covered with tunnels often makes the landscape look like a sea of plastic stretching into the distance.
While labor intensive and requiring large amounts of plastic, this method is really the only cost effective option for growing low value Winter crops in freezing temperatures. Not to mention perhaps the only cost competitive method of fulfilling demands from local supermarkets needing to stock their shelves with fresh, local produce.
Propane gas heated greenhouses are also incorporated into Japan’s Winter farming strategies, but these are mainly employed for growing higher value crops. In late Winter, greenhouses are also important for production of seedling stock in preparation for the coming Spring’s growing season.
The cost of a single lettuce in Japan can be almost three times more in Winter than in Summer. Much of this difference in price comes down to the resources, effort and the amount of plastic required to fulfill supply.
So, while shoppers may think nothing more of the lettuce they just scanned through the time saving DIY scanning checkout, it should be known that there is huge amount of very necessarily work, plastic and cost involved in protecting and getting that very lettuce into the customer’s Winter groceries bag.