Japanese Winter temperatures plunge below freezing on a regular basis, despite skies often being bright, clear and sunny. In these low temperatures, seed germination is usually impossible and growth usually grinds to a halt in any open air farming environment. Snow and frost damage is also a very likely risk for most unprotected crops. Greenhouses are therefore an important part of farming in Japan for both large and small scale operations. Die hard DIY gardeners also use greenhouses to produce home grown food for their close knit families, friends and communities.
Busy supermarkets require vegetables to sell throughout the Winter season regardless of weather related hardships for farmers and their crops. The farmers’ overall growing cycle and the propagation of seedling stock must also continue in all weather conditions to ensure seedlings are available for the coming planting seasons. This is particularly important for rice production, as the young seedlings produced in Winter are vital for the later planting of paddies in what is perhaps one of Japan’s most important crops for food production and sustainability.
Relatively simple plastic covered greenhouses go a long way to help protect crops against the cold, frost and snow for many farming operations. Black rubber or plastic ground covers on the floors of greenhouses also helps increase the absorption of sun rays and increases greenhouse temperatures for plants.
Artificially heated greenhouse operations however, allow even more flexibility to farmers in terms of what crops they are able to grow during Winter. Propagation of seeds and potential for growth of plants can be significantly boosted inside these greenhouses, no matter what the weather conditions outside. For this reason, heated greenhouses are widely used in Japan in numerous fields of farming and are extremely important for the farming strategies and planting cycles employed.
Artificially heated greenhouses found in Japan vary from relatively small and simple “metal hoop” and plastic structures, to large, elaborate commercial “buildings” covered in multiple layers of glass or plastic to maximize heat capture efficiency. Most artificially heated greenhouses use either electric or propane gas to power their heating systems.
Due to the added expense in building and running the heated greenhouses, they are usually reserved for larger scale operations growing ornamental plants for shops and higher valued vegetable crops. They also play an important role in guaranteeing the massive requirement for commercial production of seedlings for rice farmers who choose to buy trays of rice seedlings at paddy planting time.