If you want to grow underground why not just live underground? You can purchase an old U.S. Air Force Atlas-F or Titan 1 missile complex for somewhere between $150,000.00 and $2,000,000.00 and have anywhere from 5 fenced in acres to 100 fenced in acres.
　
The Atlas-F ICBM sites were the heaviest constructed of all U.S. missile sites during the Cold War. They were designed to withstand a direct overhead blast (airburst, not ground burst) of a "Big Ivan," a 100MT nuclear device, the worlds most powerful ever that when tested only had half the fissionable material added so it was roughly 50MT when detonated at 10,500 meters every seismic recording station around the world recorded the blast quake.
　
The structures were designed to withstand 10,000 psi of blast pressure and the two 3-foot thick blast doors were also made to withstand 10,000 psi of blast pressure. They were so heavily constructed that when the pyramids have eroded away to nothing but small mounds in the sand these places will still be as strong as the day they were constructed.
　
Two 3-foot thick blast doors made to withstand 10,000psi of blast pressure ….. no cozzer is kicking that in, in the middle of the night, not even if they brought a SWAT team and an Army regiment with them.
　
They have three phase electricity so you would never be wanting for enough electricity no matter what you did. They have fresh air intake systems with filters on them for chemical, biological weapons and will filter out any radioactive particles.
　
Because they are so deep underground weather conditions do not effect you in the least. It could be 120 degrees or 80 below zero and you would never know the difference and your heating bills would not go up at all no matter how cold it got. You wouldn’t need A/C because at that depth the ground, and the complex, will always want to be at 58 degrees so you would only need heat.
　
Other than the small, but very thick and sturdy cement entrance and the first of the blast doors there is no exterior maintenance to ever do. You never have to put a roof on one, you never have to clean or replace the gutters on one. You never have to paint or stain or replace the siding of one. You never have to replace a broken window or even wash a dirty window. A dozen tornadoes could tap dance above you and pound on your door all day and all night and you would never hear a single thing and there would be nothing found later that could be described as being damage.
　
Another option is one of AT&T’s old Cold War national communications bunkers they have been selling off now for a few years. They range in size from about 6,500sq. ft. to 15,000sq. ft. and like the missile sites are on fenced in lots, all 5 acres or larger.
　
They are not real deep and not nearly as heavily as constructed as the USAF missile sites but they were still built to withstand a pretty good wallop. They had the 10,000 psi blast doors and the same sort of air filtration system but they are only 4-foot thick concrete that is encased in a thick layer of lead and then a layer of steel and then have on average about 5 feet of earth above them.
　
The "Long Line" communications bunkers on average cost more than say an Atlas-F missile site but then while not as deep or as strong they are no less that 3 times larger than the Atlas-F sites and as much as about 7 times as large (that is unless someone would build in the actual missile silo itself and then they would have a MASSIVE amount of square footage, and that is interior space, and they are shaped in a way that is more homeowner friendly. They are square or rectangles and the Atlas-F sites are two level round/cylinders with a MASSIVE steel reinforced concrete pillar in the center.
　
I have considered one, I have talked with Realtors and owners and even with AT&T but so far I have not found one in an area I wanted to live in that was in a condition I wanted to tackle. Some have luxury homes above them and the underground units are luxury units and some have been flooded with water for decades and others are anywhere in between. It just depends on how much money someone has to spend, how much of a project they are willing to take on and if they can find one of these structures in an area they would like to live in.
　
But if you want to grow underground then there is the perfect solution. Structures that in today’s dollars would cost hundreds of millions of dollars to build that are now able too be purchased for around $150k and up. Not a bad value.
If you have a cool $2mil lying around there is a Titan 1 missile site on 100 acres in Colorado. Without building in any of the 3 missile silos you would have roughly 72,000 square feet to wander around in. There is a 3-mile long underground tunnel running from one end of the underground complex to the other. To give you an idea of how much space they have, a Titan 1 missile site in Oklahoma was made into a town high school … and it isn’t some little Mayberry-sized town either.
　
So why dig a 12’ by 12’ foot hole in the ground when you can have a structure that is almost indestructible … it would literally take a direct or near direct ground burst from a nuclear weapon to destroy them … the structures would laugh off anything less … so if you are going to go for it .. why not go for the gold? If you are going to dream ...... dream big!
　
An Atlas-F missile site or an AT&T "Long Line" communication bunker would do you proud.
