PHOTO: iStock/Thinkstock
April 13, 2016

A greenhouse is a practical, rewarding solution and is the best way to extend your growing abilities. Whether you choose a kit, a custom design or a do-it-yourself project, selecting one style from so many options can be intimidating. The most successful greenhouse gardener is the one who researches before they dig in. Before you invest in one, consider the following.

Your Growing Goals

The type and size of greenhouse you’ll need depends on how you plan to use it, and the larger the structure is, the more flexible the use will be. For example, if you only want to start your garden early by sprouting your own seedlings, a simple and inexpensive cold frame, aka “miniature greenhouse,” should fit the bill. A medium-sized greenhouse can double as a potting and tool shed, and a large, grower greenhouse will have plenty of room for seeding, storage, and even growing fruits, vegetables and flowers during the coldest months.

Finding A Greenhouse In Your Budget

Plants are expensive, but greenhouses can also be pricey, along with the additional cost of outfitting your investment. Associated greenhouse costs can include:

  • plant benches
  • heating and cooling systems
  • insulation
  • grow lights
  • a water source

Greenhouses also require sunny, level real estate. Don’t forget to include your time, because greenhouses can’t be successful on their own.

You’ll be surprised at how quickly you can fill a greenhouse, so if you have the money and the space, many experienced growers recommend building or buying a larger structure than you currently need. If you can’t go bigger, check into features such as multi-tiered shelving and plant hangers to organize and maximize your growing space.

Choosing Greenhouse Building Materials

Successful, attractive greenhouses can be made of various materials, and all have their pros and cons.

  • Glass lets in the most light, holds heat well and virtually lasts forever. It’s also expensive.
  • A double-walled polycarbonate covering is becoming more popular because it’s moderately priced, is easy to install and has a long lifespan.
  • Fiberglass comes in many different grades lasting from three to 20 years, but is highly combustible and easily damaged by hail.
  • Polyethylene is often used in kit greenhouses because it’s inexpensive, but will quickly buckle under snow, hail, and wind.
  • Plastics will yellow over time, reducing their light-transmittance abilities.

If your winter is generally harsh, you’ll need a greenhouse made of materials that hold heat well and can bear the weight of snow and ice. For heat, your options are primarily electricity, propane and natural gas, but remember that if the power goes out, your plants will be helpless to the elements.

For more moderate winter temperatures and hot summers, go for materials that provide better UV protection. In Southern states, you may be able to manage without a dedicated heating system, but a mechanical ventilation or mist system with circulation fans will probably be necessary.

Pick A Sunny Location

Your plants will need at least six hours of direct sunlight each day. Most experts recommend an east-west orientation in northern states and a north-south placement in southern states. Where the weather is hot, nearby shade trees work well to protect tender spring seedlings and allow more winter light after they’ve shed their leaves. Just remember to locate your greenhouse far from the threat of falling branches.

Check Your Zoning Laws

Before you build or start shopping, investigate any local ordinances and necessary permits that might be required for adding a greenhouse. Hobby greenhouses may not need a building permit, but depending on local zoning requirements, the size of your structure and the location related to your neighbor’s property lines, it’s a good idea to check.

Always Keep Learning

“I rarely have a customer who hasn’t already been thinking about a greenhouse for at least a year,” says Dan Barry, head of sales at Hartley Botanic, offering custom-built greenhouses and accessories. One book he recommends is Greenhouse Gardener’s Companion (2000, revised) by Shane Smith. “I know some customers that actually keep a copy in their greenhouse.”

A greenhouse is a long-term investment, so just as you plan your garden, plan carefully before you build, and then enjoy your growing dream come true.


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