How to Design a Greenhouse or Walipini

Growing year round. It may seem like a dream in some wintry environments. But if you have the space and means to build a greenhouse, it can be a reality. There are a lot of options for how to design and build your dream greenhouse. Your local climate, space available, and budget may determine what you end up with. Here are some things to consider when planning how to design a greenhouse or walipini.

Should I Build a Greenhouse?

A greenhouse is traditionally an enclosed structure that protects the area inside it from harsh weather so you can grow sensitive plants. The earliest known greenhouses were found in Roman ruins from thousands of years ago. It’s not too suprising that a culture known for engineering found a way to grow Mediterranean fruits and vegetables even in the far northern extremes of their empire. Back then the structures were solid walls with thin translucent sheets of mica on the roof to allow the sun’s rays to provide heat and light into the protected space. Modern greenhouses use glass or polycarbonate plastic for their walls and roof to maximize sun exposure.

Greenhouses with large areas of glass or plastic can lose energy very quickly in a cold climate. So they may not be the right design for every garden. You should build a greenhouse if:

• You only plan to grow for spring, summer, and fall, or you only need a few degrees of temperature protection to keep your plants growing over the winter.
• You have a significant budget to spend on a well insulated structure and/or you can afford to pay for supplemental heating if needed.
• You intend to integrate your greenhouse with your living space.

Should I Build a Walipini?

If you need significant temperature protection, but don’t have the budget to build a fully weatherproofed solarium onto your house, there are other options. Some gardeners advocate for greenhouses that are protected by being partially buried in the ground. One of the most famous designs is called a “walipini”. An advocacy group published plans for a project to encourage small land owners in South America to build trench-style greenhouses. These plans became popular in the United States. The key for making an earth sheltered greenhouse work is to tailor your design to the correct sun angles for your latitude.

Earth sheltered greenhouses can be very efficient to run and provide a lot of temperature-controlled growing space without needing a lot of supplemental heat. But they can be tricky to fit into your landscape. You should build a walipini or earth sheltered greenhouse if:

• You have a south-facing slope that gets plenty of unobstructed sun throughout the cold season.
• You have access to earth moving equipment. Or you can hire someone to dig a large trench with precise specifications.
• You can provide heat sink materials like stone, water containers, or other heat absorbing items that can provide passive heating for your design.

Should I Build Heated or Unheated?

The decision to heat your greenhouse or not depends mostly on what you plan to grow and if you can afford to provide supplemental heat if you need it. There are tons of ways to improve the efficiency of your greenhouse. Getting the sun angles just right, storing water in dark containers to provide a heat sink, and making sure you keep the cold wind away from the structure can work wonders. But if you want to grow very tropical fruits or veggies, you will probably have to provide some supplemental heat.

Heating comes in many forms. Here are some heating options to consider:

• Natural decomposition of organic matter can generate a lot of heat. Storing your compost pile in the greenhouse can provide supplemental heat and good soil to add to your greenhouse beds.
• Burning wood can be a renewable heat source, especially if you have your own source of woody biomass. Rocket heaters or small woodstoves can efficiently provide heat for a greenhouse space. However, they can require a lot of oversight to maintain constant temperatures.
• Electric or fossil-fuel fired space heaters can be set up with thermostats or other automated methods to keep your greenhouse at the right temperature. As long as the fuel tank is refilled or the heater is plugged into the grid, they can operate as long as you need them. But they are the most expensive supplemental heating option.

If you want to grow plants that will require supplemental heating, you have to have the budget for it. But it can make your greenhouse much more successful. It opens up the opportunity to grow almost any plant at any time of year.

Next Steps

If you’ve considered all your options and made some decisions, it’s time to get started with planning how to design a greenhouse or walipini. Make sure you lay out all the necessary materials, tools, and equipment so you have an accurate budget before you start. These kinds of garden projects can get expensive if you’re not careful, so crunch the numbers at the start so you know what to expect. Then, once you have your design, take action and start your build. You’ll be enjoying hothouse tomatoes or a banana from your own tree in no time. Good luck!

Not sure if you need a greenhouse to grow your favorite plant in your area? Knowing your USDA hardiness zone for your garden and for your plant can help. Check out my blog post on What is a Hardiness Zone for all the details. Enjoy!