What to Consider Before Buying a Greenhouse

With winter on its way, some gardeners are calling it quits and parting with their plants for the year. Others realize that the joys of gardening need not cease at the end of October. By buying a greenhouse, you can enjoy warm-weather flowers, fruits, and vegetables all year long.

You can buy your greenhouse at a local garden center, a hardware store, or online. Prices vary from anywhere between $300 for a basic setup to several thousand for more large-scale structures. But before you go shopping around for the better bargain, you need to determine what type of greenhouse is right for you. Your decision will depend on several factors.

1. External Climate

The climate where you live impacts the temperature inside your greenhouse. In general, a freestanding structure will allow you more control over greenhouse temperatures because it will be exposed to more regular sunlight than an attached greenhouse, which will be frequently shaded by your house, depending on the time of day.

2. Internal Climate

What temperature would you like to maintain inside your greenhouse? This factor won't affect what greenhouse structure you'll need, but you may have to purchase some extra hardware to maintain your desired temperature. Greenhouse heaters can be powered by gas, propane, or electricity. Depending on the climate, you may only need to run the heater overnight.

If you just plan on starting or housing seedlings through the winter, a "cool greenhouse" that stays around 45 degrees Fahrenheit should be sufficient. You can protect your plants from winter frosts by covering your greenhouse with bubble insulation, available at most hardware stores. Some gardeners say a swimming pool solar cover works just as well.

You may need to up the temperature if you want to grow tender perennials, most of which will do well in a "warm greenhouse" with temperatures around 55 degrees Fahrenheit. To do this, you'll need to buy a greenhouse heater.

If you plan to grow tropical plants, which require temperatures of at least 65 degrees Fahrenheit, you'll need to run a more powerful heater, possibly day and night depending on the weather in your area. This type of greenhouse, known as a "hothouse", is the most expensive to maintain.

3. Stability

Another thing you should consider before running out to the store is whether you want a portable greenhouse or a permanent one.

If you live in an area with severe temperatures and lots of wind, you may want to take down your greenhouse and store it during unfavorable weather periods. On the other hand, some permanent greenhouses with foundations, while more expensive, may be sturdy enough to withstand harsh weather conditions.

4. Cost

A freestanding greenhouse may require a larger investment in electricity and heating since it stands apart from the rest of the house. Despite fluctuating temperatures, an attached greenhouse may lower your electric bill, since the heat generated inside the structure will help to warm your house. Plus, attached greenhouses carry the added benefit of convenience: simply step out the back door of your house, and you're in your garden paradise.

5. Permits

Evaluate your gardening needs to determine which type of greenhouse is right for you. Once you've decided, there's one last thing you need to do. Before you go out and buy your dream greenhouse, call your local building department and find out if you need a permit to build one in your area. In most towns, hobby greenhouses don't require a permit, but it's a good idea to find out before you go out and buy yours. The last thing you want is to spend a bunch of time and money on your greenhouse only to get a call from a local official ordering you to take it down.