Here is the third idea.
Build an aquaponics system for high-output vegetables and fresh fish
It might seem daunting at first, but raising fish and using their waste to grow food crops without soil, a process more popularly known as aquaponics, can actually be quite simple. Raising fish in small water tanks generates ammonia-containing waste, which can then be converted into nitrite for fixation in growing soils. Nitrite is then converted into both nitrobacter and nitrospira, two substances that are crucial for maintaining the necessary nitrogen cycle, which promotes plant growth.
“Fish excrete ammonia in their wastes and through their gills,” explains aquaponics expert Rebecca Nelson in a piece for the Aquaponics Journal, which explains how to build your aquaponics system at home. “Nitrifying bacteria, which naturally live in the soil, water and air, convert ammonia first to nitrite and then to nitrate… [which] is used by plants to grow and flourish.”
Since pre-built aquaponics systems can cost thousands of dollars, building your own may be the preferable option. Aquaponicsideasonline.com provides resources and a wealth of information for building and managing an aquaponics system. http://aquaponicsideasonline.com/.
On the next page are 12 ways to become more self-sufficient.