There is a growing need for safe, healthy, and natural food items, and what seems like a decreasing amount of space to grow healthy organic food in nutrient-rich soil. Growers are always looking for methods which will save energy, reduce pollution, grow more and higher quality crops, and they want something that is affordable. Underground greenhouses are a preferred method for the environmentally conscious grower.
Underground greenhouses can be constructed within a wide variety of geographic and climatic conditions, and because the ground is warmer in the winter and cooler in the summer, you are creating a far more stable micro-climate than growing outside. Typically, the design is built three to five feet underground, and the setup allows for the collection and storage of daytime solar radiation. Growing can be done all year long regardless of the weather conditions, which is why the underground greenhouses are referred to as the Walipini, meaning the “place of warmth”.
The greenhouse is covered with plastic sheeting, and the longest area of the rectangle of the design faces the winter sun. For the Southern Hemisphere it would face to the north, and vice versa for those in the Northern Hemisphere. The depth of the project allows the farmer to utilise thermal constant temperatures, enabling food to grow in colder weather conditions. The underground, nature-friendly method has been around for decades, and proven to be an efficient design which utilizes nature’s resources in order to provide a stable and warm environment for year-long growing.
Angle of the Roof to the Sun
The angle of the roof makes a difference on the sun’s ability to heat your greenhouse. The roof should be facing directly on 21/21December at a 900 angle. This angle will maximize the heat during the winter solstice and minimize the heat during the summer solstice.
The angle of your roof will depend on your latitude. Find out your latitude and then add 23°. This number will be the angle of decline that you will need on your roof.
Solar greenhouses rely mostly on sunshine for growing, and the crops are not determined by weather conditions. For those growing in areas such as western China, this method has proved to be resilient and effective. The greenhouses have enabled farmers in diverse regions to vastly increase farming output, producing vegetables during a time of year that they otherwise wouldn’t have produced. The underground greenhouse method has consequently revolutionised the surrounding economy there.
Ma Junxian, from Guyuan City, makes at least 20,000 yuan (2,941 U.S. dollars) in yearly annual income by growing celery, broccoli and chilli throughout the year in his 667-square-meter greenhouse. The earnings are 10 times as much as what he is used to earning when he had been growing using more conventional farming methods which rely solely on the weather for a harvest.
The underground greenhouse method allows for natural insulation, while optimising solar absorbance. These partially subterranean greenhouses appear to be the best for growing winter horticultural crops, and have been adopted in numerous countries, such as Japan, Russia, Korea, and now even the United States. These underground greenhouses can be something built very small for an individual or family, or it can be much larger to accommodate for more commercial needs. But it has proven to be more beneficial for growers than conventional methods which are at the mercy of varying weather conditions. Cheaper than aquaponics, but more effort than urban homesteading, an underground greenhouse is almost universally viable, more than affordable, and ecologically smart.
*cross-posted from http://csglobe.com