There are many ways to grow food, from the most basic and obvious being to drop seeds on the ground, drop water on them and hope something grows, to very advanced methods of growth where you grow the food in the air itself! Some methods of food growth don't even use the sun at all!
Aeroponics and Vertical Farming
A greenhouse uses the sunlight to trap heat generated by the place that it hits and holds onto it for hours. What makes a Walipini green house so different is that it uses the heat from the earth with the heat from the sun to generate even more heat.
A walipini greenhouse is sunken into the ground where the heat from the earth is between about 50-65 degrees naturally. This allows for more stable temperatures no matter how hot or cold it is outside as the temperature naturally tries to stabilize with the earth's temperatures beneath it. This allows for far less power consumption in order to keep it warm in the winter.
Natural Heating with Compost
Composting is a great natural and energy efficient way to heat a green house. In fact, the only energy needed is what it takes to make and move the pile! A compost pile can have temperatures upward of 140-160 degrees. It can also last several months and up to 2 years, with the final result being great fertilizer.
According to the Environmental Protection Agency, "Food scraps and yard waste together currently make up more than 28 percent of what we throw away".
Some designs incorporate the heat of the compost into other things, such as heating water. It may even be possible to heat a house with compost!
Most people know that a plant needs light, water, and nutrients, but these forms can be varied and in some cases produce even better results than their natural alternative. Every plant needs light, but it doesn't have to be sunlight. Many growers are using man made lighting to grow with. For years it was high pressure sodium, then it moved to Fluorescent bulbs, and now light emitting diodes (LED's) are being used. In fact, plants don't need the yellow spectrum of the sun, so some growers are using ultraviolet spectrum LED's in order to save on energy costs.
Water is obviously needed in plant growth, but what if I told you that there are better ways to give the plants what they need and save on most of the water typically used in gardening? There are a few types of gardening that utilize these water saving methods in their plant growth and have better results with it.
One of them is called hydroponic gardening. It actually has a few varients to it all with different names such as aquaponics and bioponics. These methods of growing utilize a pool or bath of water that the plants grow in instead of soil. Often times, they will have some sort of medium in it that helps hold the plant in place, but aside from that just has roots in a nutrient water.
The other type is known as aeroponics, and it's where the plants are grown with the roots just hanging in the air, though they are misted with a nutrient water mix very often or constantly giving it a high air to water ratio.
The other aspect of growing is the nutrients. While common gardening will usually employ only or mostly what's found in the ground on site, methods such as hydroponics often use a scientifically engineered nutrient mix to get the best results in their growing. Other growing methods use all natural nutrients such as Bioponics does.
While further methods such as aquaponics will use a cycle of life natural method to have each thing feeding another thing in a full cycle without needing any outside source. For example, with an aquaponics system it is typical that you would grow the plants in a water based nutrient pool similarly to how you would with a hydroponic system but the nutrients for it come from an algae that break down fish poop. The algae get to eat the fish poop, in this process feeding them, and the fish get to eat both the algae and what the plants produce. Each method varies, but in some worms are used and compost piles as well. The overall design will vary mostly depending on what type of fish you use, as some fish are herbivores (plant eaters), and others are carnivores (meat eaters), so worms and such may be needed in order to complete some cycles.
There is even a new method that has been used in recent times known as "vertical farming". This method uses the same basics as aeroponic farming or hydroponic farming, but it stacks them using artificial lights between each layer instead of just one layer total in order to maximize the growing area where height is typically wasted.
A more natural way to grow food and more traditional way is known as a "Food Forest". It's a method of growing said to be utilized by the Native Americans long ago. A food forest is typically an all natural area of food growth that maximized growth with several types of plants (potentially animals and bugs as well), all in a very low mantainance way. This allows nature to work as it does best while maximizing your food return.
There are seven layers to take into consideration with a food forest.
1. A "canopy layer" that is the larger fruit and nut trees (or preexisting trees), and will ensure the land will not get scorched by the hot sun causing a nice cool breeze on those hot days.
2. Dwarf trees will cover this layer and are typically more fruit and nut trees and will also ensure the sun doesn't scorch the land.
3. This layer is even closer to the ground and will cover bushes typically of berry varieties.
4. An "Herbaceous layer" typically of basic edible plants such as medicinal herbs, along with plants that bees and chickens like to eat.
5. This layer will be your ground cover layer. It will assure that the ground is fully covered as grass would typically do ensuring that the ground stays moist even when it hasn't rained recently, almost like a skin for the earth. This layer should also be planted with edible plants. (Mint is a great smelling ground cover and flavoring.)
6. This layer will take advantage of the under side of things as you would typically plant root based plants here such as carrots, potatoes, and beets.
7. The final layer to consider is one typically overlooked and that is the vertical layer! This layer typically contains vines, so grapes are a great thing to grow here.