Underground Greenhouse Designs For Year Round Food and Food Protection

People all over the world have been using an underground greenhouse for ages. Once you dig down about six to eight feet underground, in most places in the world the temperature stays a fairly constant 50 or 60 degrees year round. This makes it possible to:
• grow a garden year-round in the sweltering desert or freezing mountain top, no matter what the weather throws at you
• Hide your garden out of sight
• Keep animals and scavengers out
• Combine ancient and modern ideas
• Build to your exact needs and climate

Growing your own food is important, but in a complete collapse situation it’s also important that you can protect your food. Are your neighbors as prepared as you? They won’t think to ask permission when they are starving.

An underground greenhouse is easier to protect. There are many designs that you can make even safer with the addition of some security features. It’s also easier to keep animals out and control the environment that you grow your food in.

Underground Greenhouse Design

From Nepal to Brazil you can find tons of different ways to build an underground greenhouse. But there are several things you’ll need to think about in your situation.

How you build your underground greenhouse will make a big difference in how well it performs. This video gives a good idea of how different designs for an underground greenhouse will work at different times in the year.

1. Climate, Weather, Location

Even though you’ll find a lot of shelter from the elements six to eight feet underground, you’ll still need to think about where you live. How much direct sunlight do you get each day? The direction your roof faces and the angle you use on the roof will change how much sunlight and warmth gets into the underground greenhouse.

What about floods? An underground greenhouse needs to be above the water table and it’s not the best idea in an area that floods often. In some areas, drainage and pumps can help protect against a flood.

If you live near hills, you can build into the side of one. This means you don’t have to dig down so far and you have the added security of a sloped roof that blends into the landscape better. Digging an underground greenhouse right up next to your house gives you an efficiency bonus because the heat from your house will help the greenhouse stay warm. Plus, your existing security system can be extended a bit to keep it safer without a lot more fuss.

 

Image from Aerin Aichi via Wikimedia Commons

2. Security

The security of your underground greenhouse is another factor to consider. It’s a lot easier to keep deer and other animals out of an underground greenhouse than a traditional garden plot. But people are smarter than animals.

You might think that your neighbors wouldn’t break in and steal your family’s supplies, but think twice. When people get hungry, they won’t just passively lay down and starve to death. They will be coming for your hard work and they won’t care how they get it.

There are plenty of designs for underground greenhouses that would be pretty easy to break into. But you can adjust your plans to make sure you have a door that locks, sturdy roofing instead of flimsy plastic, and materials that keep your investment safe.

Of course, one of the biggest advantages of an underground greenhouse is that it’s tucked away out of sight. This might not help guard against your immediate neighbors, but it does help you protect against people roaming the area looking for an easy mark.

At the one minute mark of this video you can see a very small underground greenhouse built flush to the ground. This greenhouse is not well planned but it is nearly completely hidden. I would not recommend this design to supply your entire family with food, but in a pinch or with extremely limited supplies and space, this design will keep your food hidden from view.

3. Types and Amount of Food

The size of your underground greenhouse will most likely be determined by the cost to build it and the area of space you have. But it’s still worth thinking about how much food you will need to grow to feed your family.

You’ll also want to design the environment so you can have the best growing conditions for the kinds of food you want to grow. When making that choice, you’ll want to focus on plants that grow quickly, have big harvests, and give your family a lot of nutrition.

Image from Aerin Aichi via Wikimedia Commons

Hardy and easy to grow vegetables like potatoes, beets, cabbage, tomatoes, and kale will give you big harvests for an extended period of time. Plus they can be used in lots of different recipes and even preserved for future use. Fruit can be a little more difficult since a lot of it grows on trees, but some berry bushes can help you keep variety in your diet and they are pretty agreeable to growing in an underground greenhouse.

Don’t forget about herbs as well. They might not have the same nutritional content as other plants, but they are pretty easy to grow. Just because it’s the end of the world doesn’t mean you want to sacrifice the taste of your food.

This video shows a walipini (underground greenhouse) in its second year of growth. One thing to learn from this video is that if you live in an area of the world that gets snowfall, you’ll have to take the time to sweep the snow off the roof in order to let the sunlight through. Otherwise you can see what an underground greenhouse looks like when it’s had time to grow up a bit.

4. Other Storage Spaces

An underground greenhouse is about the same temperature as a root cellar. This makes it a great place to store other foods and equipment for survival, such as water. When you’re designing your underground greenhouse, consider adding a small room that doesn’t get direct sunlight. You can keep root vegetables and water barrels down there, and it will already be secured with your security system.

5. Growing Equipment

Depending on your budget and climate, you might want to have a more efficient growing system in place. For example, instead of planting in soil you might want to work with hydro or aeroponics. Growing in air or water takes different supplies and a dedicated set up, but you can get much faster and more frequent harvests.

Those techniques might make the most sense if you need a dig a smaller underground greenhouse but can’t afford to sacrifice the amount of food you’ll get out of your project. At the same time, you’ll have to buy lots of different types of equipment and do more research to make sure your setup will work well.

It’s worth looking into if you’re already going to be building an underground greenhouse. You’ll already have so much time and energy into the project that you don’t want to cut corners now if it means the survival of your family is on the line.

In this video, you can see an underground greenhouse that has just been finished and doesn’t have plants in it yet. This guy is set up with a pond in the middle of the greenhouse where he can have fish. Eventually, he is going to set up a hydroponic system for growing plants, which is why the pond exists. Notice in the video he starts from the outside and you can see that there is snow and ice on the ground. But when we walks into the greenhouse, the pond isn’t frozen over. This is proof of how well this setup works to keep the temperature warmer. He’s also got a nice berm surrounding the greenhouse, which lets the dirt work as extra insulation.

Parts Of A Underground Greenhouse

The design of your underground greenhouse is going to play a major role in how each part of it is built. But there are some basic things to keep in mind no matter what design plans you go with. Here are some things to think about for each part.

Irrigation and Drainage

The floor of your underground greenhouse isn’t just the part you walk on. You’ll need to keep irrigation and drainage in mind. A thick layer of gravel underneath your topsoil is one way to accomplish this. Make sure to put in a few different layers of gravel with the bigger stuff at the bottom and the finer stuff just below the topsoil.

You can get fancier with a piped irrigation system if you like. Dig trenches and lay down soaker hose. Make sure everything is sealed tightly with rubber cement. Don’t forget a pressure regulator and something to prevent backflow.

Walls

Materials like steel are sturdier and more secure, but something like clay or brick will be natural insulation. You will want the walls to have a slope from roof to floor.

Roof

The roof of your underground greenhouse will trap heat, protect your garden from rain and snow, and determine how much sunlight is let into your underground greenhouse. The angle of the roof is very important.

You want your roof to be angled so that on the winter solstice (the shortest day of the year with the least amount of sunlight) the rays from the sun hit the roof perpendicularly. This angle will maximise the sunlight you get all year round, even in those cold winter months. To do this, add 23 degrees to your latitude.

Many underground greenhouse designs include a roof that angles in both directions, but if you plan to go with one sloped roof, you want it to face South if you live in the Northern hemisphere and North if you live in the Southern hemisphere. Again, this is to maximise the energy from the sun in your area.

Don’t forget to include a rain gutter to prevent soil erosion, and with the bonus of gathering rain water. With some simple piping and planning in advance, you can pipe that water right into a collection point inside your greenhouse.

Image from Aerin Aichi via flickr.com

Door

You will need a door to enter the underground greenhouse with a ramp, ladder, or steps up to the surface. The door will need to be secure to prevent people from getting into the greenhouse. You’ll also want to make sure the door is well insulated because this is one of the biggest places you will lose heat and let the cold in.

Ventilation

Ventilation is crucial. Remember, you’ll want to avoid using fans or other electric solutions for ventilation, but something as simple as a chimney can be the answer.

Building An Underground Greenhouse

Homesteadoconomics has a great video series on building an underground greenhouse. In this first part, you can see the him digging out the area, mostly by hand. His father in law comes in with a backhoe after a while and you can see that it makes a huge difference. For a bigger greenhouse, it would definitely be worth the time and cost to rent some equipment. Digging by hand is easy for about a foot into the ground, but it gets a lot more difficult the further down into the earth you go. He pours a concrete footer to support the door of the greenhouse. In the video he talks about his ideas for each step and how the final greenhouse will work.

In part two, he’s got more of a structure to his underground greenhouse in place. In the first part of the video he shows how he poured the concrete footer and did some masonry work to support the roof and door frame. One piece of advice he uses is to skip the ready-mix bags because it ended up being more expensive than if he had just gone another way. The greenhouse is starting to take shape in this video.

In part three, the greenhouse is nearly complete and looks a lot more like a greenhouse. This design isn’t as concealed as some others are. He built a series of rafters instead of using ready-made trusses and that was a good choice for the offset roof design. One thing to notice is that he framed in a vent window and mentioned added one or two more. He bought panels for the roof for easy installation.

Survival Garden

It can be a big task to figure out what plants you’ll need to grow in your survival garden. There are lots of resources online to help you figure out what you need to plant. This article https://www.gardeningknowhow.com/edible/vegetables/vgen/survival-garden-how-to.htm will explain a bit more about survival gardens if you’re new to the idea.

Basically, there will come a point where the food you’ve stockpiled and preserved will run out. You’ll need to turn to hunting and growing your own to make this happen. Not everyone goes for the underground greenhouse straight away, but think about it. If you rely on a “secret” garden in the woods, you’re putting your food source in danger from animals, savvy scavengers who know what to look for, and a whole bunch of different natural disasters that could be the whole reason you’re surviving on your own in the first place.

It’s not a bad idea to have a stock of seeds somewhere or to have patches of edible foods growing out in the open. But building an underground greenhouse gives you a lot more control and protection in case of natural disasters or widespread pollution.

What To Plant in Your Underground Greenhouse

The whole point of an underground greenhouse is that you can grow year round. This means you aren’t limited to one season of growth to prepare food for the entire year. Even then, you’ll want to be prepared so that a bad year doesn’t force you to starve to death.

This article http://www.wellfedhomestead.com/how-much-should-you-plant-in-your-garden-to-provide-a-years-worth-of-food has a great chart that shows you how much of each plant you should put in a garden to help ensure that you have enough of a yeild that everyone gets enough to eat. A lot of the plants listed there are great ideas for an underground greenhouse.

Broccoli

Did you know that broccoli is a better source of calcium than milk? It’s also easier to grow in cooler seasons, which makes it a great idea for an underground greenhouse in areas of the world that get extremely cold. Even though being underground will do a lot to regulate the temperature, northern areas of the country will still have to battle cold to grow enough food to survive.

Cabbage

Cabbage is a good survival food that has two natural seasons, making it a great choice for an underground garden because it can thrive well in cooler temperatures. One great thing about cabbage is that it has the same nutritional value no matter how you cook it. Unlike a lot of other vegetables that lose nutrients when they are cooked, cabbage still gives you a big dose of vitamins.

Corn

Corn can be picky about soil and it takes up a lot of space vertically. But if you can grow it successfully, it is an amazing survival food that has a lot of energy and can be used a lot of different ways.

Kale

Kale has a ton of vitamins and minerals in it and it’s very good for you. You can dry it and crumble it into soups and stews for a huge boost of nutrition, even if you don’t like the taste. Kale is also a good choice for an underground greenhouse because it does well with cold weather (and might even taste better if it’s lived through a frost).

Potatoes

Potatoes are a staple in diets all over the world. They are a good pick for an underground garden, but they work well in containers too. You can plant potatoes in a barrel and add hay or dirt as the plant grows. It will naturally grow to the top and leave a trail of potatoes all the way down.

Squash

Squash is something you can store for a long time and it will stay ready to eat, which makes it a great choice for a survival garden. There are lots of different kinds of squash, so you can probably find something that everybody in the family likes. Depending on the type, squash can grow year round.

Tomatoes

Tomatoes are easy to preserve, versatile, and full of flavor and nutrition. Plus, with the right soil and sunlight you can grow a lot of them on one plant. Tomatoes are sure to be an important part of an underground greenhouse design.

Herbs

Don’t forget the herbs! You might not think herbs will make that much of a difference when the end of the world is here, but what’s the point in eating bland food when you can have delicious fresh herbs? Lots of herbs are easy to grow and versatile, such as oregano, basil, and cilantro. They pack a lot of flavor into food and they can easily be dried and used all year.