Underground Food Farms
Underground farms are entirely possible, in these farms a circular function of soil churning, water movement and natural filtering flows throughout the entire system, energy can be gathered using several methods such as solar energy and an Egyptian system of refraction.
Underground placement of a multi level farm will require a turning soil system, this system she be able section by section of churning soil and should use a form of companion plants every other cycle to prevent soil degradation. Companion seeds or plants return much needed nutrients back into the ground and permit for long term conditions of soil use.
This will requiring a irrigation system that uses a natural filter and would require some modifications to ensure each system maintains the proper levels of nutrients, certain fish types can be used to help facilitate this but should not be harvested for meat, they are part of the internal system and promote healthy vibrant biological conditions.
These farms will use a two part system of lighting one is gathered by solar energy panels to fuel batteries so that proper circular flow of air and water continue. The main stay of light flow should be through refraction based on Egyptian techniques for pyramids. These lights should refract sunlight through every floor and can be modified to refract in circles, spherical or otherwise on the node above the planting stations. Even if there are 50 layers to this it won’t matter. Any conditional excess light can be absorbed both in the station and above ground in multiple layers to maximize light absorption.
Air flow through a natural wind based system with a back up energy system can be devices to help promote oxygen and carbon exchange.
When taking into consideration that below ground use is a regulated temperature system proper use and conditions will be required to appropriately grow each plant in conditions based on temperature.
Also above ground systems can be used to maximize energy efficiency, flow for both air and water using gravity to help create effective use of force and minimize energy use. Gravity syphons are a prime example of this. Equaling out the draw and flow may take a little modification but should not be much of an issue. Very little external energy should be required to maintain this.
This can be used in some of the most desolate land areas and even deserts can become fertile lands.
Several methods of design can be used as a multi tier model not just here but even in space. Underwater too.
(I had a drawing design once I find it I'll add it here.)