If you’ve ever dreamed of having your own greenhouse but couldn’t make that a possibility, you’ll be pleased to learn that DIY mini greenhouses are becoming a popular alternative. In this case, “mini” actually describes a large range of sizes: your mini greenhouse can be a 12”x12” tabletop unit or a 2’x5’ freestanding cart on wheels. It can even be covered milk jug.
While you can buy pre-fabricated mini greenhouses, you can also create your own, personalized mini greenhouse designed specifically for your needs. Materials don’t need to be expensive, either.
Just as with raised beds, there are dozens of different ways to build a mini greenhouse. This article won’t go through all of the various designs, but it will describe the basic principles to consider when building your own. Remember, the larger your greenhouse, the more planning and construction components are required.
Location, Location, Location
Your greenhouse may well be portable, but before you determine its dimensions, decide where you will place it. Greenhouses need tons of sunlight, especially in the morning; a perfect place would be the south or southeast side of your building. If your greenhouse will only be used during the summer, don’t worry if you have a few trees that provide shade in the afternoon as long as they don’t block the morning sun. If you will also use it during the winter months, afternoon sun is critical, too.
Types of mini greenhouses
Next, determine what you want your greenhouse to look like. Will it be a free-standing greenhouse? A tabletop unit? Window-mounted? The type of mini greenhouse you choose may be based largely on its sun exposure.
You’ll also need to consider how much interior space is needed based on plant type and how you plan on accessing the plants. Removing a lid? Unlatching a small hinged door? Lifting up plastic covering? Keep in mind that the smaller your greenhouse, the harder it is to regulate its temperature due to the air volume and exposed surface area.
An essential part of your mini greenhouse is the covering that provides insulation, access to sunlight, and elemental protection. While glass is a traditional covering, it is a harder DIY material to work with. Although it is sturdier than other coverings and inexpensive to maintain, it is expensive to install and repair. Fiberglass is lighter and stronger than glass and will last years. Only clear fiberglass should be used for optimal sun exposure over time.
You’ve certainly seen mini greenhouses constructed with a plastic cover. Opaque or translucent plastic will filter sunlight differently, so take your greenhouse location under consideration. Plastic is an inexpensive option, but remember that it will degrade over time and need replacing. Plastic also provides excellent heat retention and is great for small projects.
You may need a heating system depending on the plants you are growing, location/construction of your mini greenhouse, and its sun exposure level. If nights in your region get cold, you will want to invest in a 220-volt electric heater or small gas/oil heater.
Air circulation and ventilation
Depending on its size, a mini greenhouse may or may not need air circulation. If you have a tabletop greenhouse, you are likely circulating its small volume of air sufficiently every time you open its door. Otherwise, consider having a small circulating fan in your greenhouse, lest the warm air rise to where you don’t want it to be.
For larger mini greenhouses, an exhaust fan serves the purpose of ventilation, which is essential for exchanging inside air for outside air to control temperature, replenish carbon dioxide, or remove moisture. Smaller mini greenhouses won’t need artificial ventilation methods for the same reason they won’t need artificial air circulation devices.
For designs and inspiration on how to build your mini greenhouse, visit:
A mini greenhouse built over a raised bed:
A compilation of mini greenhouse designs:
Creative Commons Flickr photo courtesy of Cy-V