8 DIY Mini Greenhouse Ideas To Extend Your Growing Season On A Budget

A greenhouse is any structure used to grow plants in a controlled environment. The clear roof and sides allow sunlight in for the plants and keep the temperature and humidity levels higher than outside the structure. Greenhouses are often large commercial structures, but home gardeners can use them, too.

On a smaller scale, a mini greenhouse can be a great way to extend your growing season. Here’s what you need to know about DIY mini greenhouses and some ideas to get you started.

Benefits of Building a Mini Greenhouse

The primary benefit of using a greenhouse is that it provides a more controlled environment for growing plants as compared to growing them outside. A greenhouse allows you to grow plants longer, even all winter, depending on what you’re growing.

Starting seeds in a greenhouse enables you to grow plants earlier in the season, but the space can also be used to protect tender plants from extreme weather, to get more harvests of fruit or vegetables per year, and to grow a greater variety of plants.

You can buy a greenhouse for your garden, but there are some benefits to building your own miniature version. Most importantly, it allows you to enjoy all the uses of a greenhouse even if you have limited space. And, you can save money by making your own small greenhouse as compared to buying a pre-built larger greenhouse.

Ideas for Making Your Own Mini Greenhouse

Enjoying a greenhouse in your garden doesn’t have to be expensive and it doesn’t require a lot of room. Use the space you have and these ideas to construct your own simple but effective mini greenhouse.

1. Upcycle Scraps

The basic elements of a greenhouse are very simple. A greenhouse can be large or contain fancy equipment, but it can also just be a structure with four sides and a top. Use scraps to build a very basic greenhouse for starting seeds or keeping tender plants warm.

Scrap wood planks, siding, or pieces of metal can be used to create the sides of a small greenhouse box. Use an old window with a hinge to attach it to the sides of the box. Alternatively, you can make a greenhouse from old windows without using these other elements, as their frames can be joined together. Even old plastic bottles can be combined to create "windows" for a greenhouse.

2. Recycle Old Picture Frames

Picture frames are ideal for creating the sides and top of a small greenhouse box. You can either use the glass that comes in the frame or remove the glass and stretch clear plastic across the frame.

Use the frames to create a box with a lid you can use to keep small plants warm or to get a head start on seeds and vegetables. If you don’t have old picture frames, they’re easy to find at flea markets.

3. Reuse Plastic Containers

For really small DIY greenhouses, use plastic containers like clear plastic cups or berry and other fruit containers, or even make a plastic bottle greenhouse.

Simply place a container over the top of a seed tray or a small pot or container to create an instant, single-plant greenhouse. The plastic will be enough to keep small, tender plants warm and moist in colder weather.

4. Use a Clear Storage Bin

For a slightly larger but equally simple solution, make a plastic tote greenhouse using a clear plastic storage bin. You can turn it upside down and place it over plants growing in an outdoor bed or over containers on a patio. Alternatively, use it right side up.

Place seed trays and small containers right in the bin. Use the lid or not depending on how much protection your plants need from the elements.

5. Enclose a Shelving Unit

An old shelving unit can be turned into a simple greenhouse with a plastic cover. Place plants or seed trays on the shelves and cover the entire unit with clear plastic.

You can find plastic covers with zipper access through a door or window. You could create your own plastic cover for less money, but the zipped covers are easier to use.

6. Upcycle an Old Glass Cabinet

Glass curio cabinets make easy greenhouses. If you have one on hand, you have a greenhouse ready to go. If not, look for one anywhere that sells used furniture: a flea market, secondhand shop, or antique market.

A glass cabinet like this is best used indoors. If you’re going to place it outside, find a way to stabilize it. It can easily tip over and break.

7. Use an Aquarium

A glass aquarium is like a pre-built mini greenhouse. Turn it upside down to cover plants or use it upright with the screen at the top as a lid.

It’s easy to find aquariums for free or low cost if you know where to look. Check local online communities where people give away or sell items they don’t need anymore. You might also find one at a flea market or secondhand store.

8. Buy a Greenhouse Kit

This option costs more than creating your own structure, but it’s also less expensive than buying a large, pre-made greenhouse. You can find kits for small DIY greenhouses online. The kit provides all the materials and instructions for building the greenhouse.

A greenhouse doesn’t have to be grand or expensive. It can be a simple plastic cup or an old fish aquarium. Use these ideas to inspire your creativity and make your own mini greenhouse.

More Growing Inspiration

• Ready to start growing? Try winter sowing seeds in your garden, giving them a little protection with a mini greenhouse or cold frame.
• Grow exotic plants under glass indoors with these 8 enchanting terrarium plants that flourish all year.
• Have you tried germinating seeds in paper towel? This easy method makes no mess and results in fast, reliable growth.
• Browse stunning flowers, delicious vegetables, and aromatic herb seeds in the Gardening Know How Shop – your go-to destination for all things gardening.

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