Tips for owning and managing a backyard greenhouse

In eastern Idaho, gardeners need every advantage to help them have a successful crop of vegetables and garden plants.

One of the best ways to extend your growing season on both ends is having a backyard greenhouse. These structures do not have to be overly elaborate, expensive, or even permanent to make a significant difference in the success rate of your home harvest.

Here are a few tips to keep in mind as you plan, design, and build your own backyard greenhouse.

Set your budget for all aspects of owning a greenhouse. This should include the initial building cost, maintenance, future replacement of the plastic or exterior covering, heating, cooling, and any extra water usage. Depending on your location and the size of your greenhouse, inquire with your local county planning and building department for proper permitting requirements, and structural snow load requirements.

Determine if you want to run your greenhouse year-round or just at the beginning and end of the seasons. This is important because a year-round greenhouse will need to be built using materials that have a higher heat retention capability. By doing this you will reduce your cost of heating the structure in the bitter cold of winter.

Snow load on greenhouses can be very destructive if they are not properly built to withstand the weight. Most of the less expensive greenhouses are designed to be taken down during the heavy snows of winter, and then reassembled in early spring to get plants started. Additionally, you will want to have a greenhouse with enough slant to the roof that it will naturally shed the snow off the top. The greenhouse plastic wrap covering that you buy at a local hardware store works well for these temporary greenhouses, but will deteriorate after 1 to 2 years of use. Wind will also shorten the life of your plastic, and if your greenhouse is not properly anchored down, the wind can make your greenhouse an airborne structure.

Select a site that has adequate drainage. A greenhouse with standing water on the floor due to poor drainage is an invitation for diseases and insects to start living and causing problems for the structure.

Select a location for your building that has a close proximity or easy access to a water source.

There are several types of building materials available for constructing a greenhouse. The most durable is a double wall polycarbonate sheeting that will last for many years, and will give the best heat retention value of the greenhouse construction materials available. The higher quality polycarbonate sheeting will have a UV protectant film applied to one side of the material to increase it durability. Unfortunately it is also expensive, and many times the only way to buy it is through a catalog or the internet. Other types of building materials are corrugated poly sheeting, greenhouse plastic with a UV treatment, and glass windows.

Ventilation is an often neglected aspect of building a backyard greenhouse, but overheating can result in heat stressed or dead plants. Design your greenhouse so that air can flow throughout, generally having vents or windows that open on both ends is necessary to achieve this. There are automatic window opening systems that can be installed on your greenhouse and this can reduce the hassle of having to open and close windows if the temperatures are fluctuating heavily.

If a greenhouse is not within your budget a cold frame may be within your reach. These are generally constructed of low cost materials, and have no heat source. They are generally made from old salvaged windows or inexpensive greenhouse plastic. The walls are generally made of wood boards, and are not taller than two to three feet tall, with the windows or plastic placed on top to allow sunlight in, trap heat, and keep the cold out.