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25 · OAKVILLE BEAVER Friday, April 3, 2009 Spring Home and Garden An Oakville Beaver Special Feature How to build a greenhouse in your own backyard Spring is in the air and the flowers will soon be in full bloom. Do you wish it could be like this all year? Maybe it's time to consider building and maintaining a greenhouse in your own backyard. The ancient Romans were the first to protect plants from nature's blast by housing them under slabs of rock on top of heated pits. By the 18th century, explorers began to create glasshouses, closer to the greenhouses we know today. But it was not until 1800 that gardeners realized light was more important to a plant's health than simply heat. In 1851, Sir Joseph Paxton, a horticulturist for a British duke and the leading landscaper of his generation, erected London's Crystal Palace, a prefabricated structure made with iron and glass -- the first of its kind in the world. Paxton's creation was a milestone for architectural design and greenhouse development. It set the stage for future greenhouse design. But the greatest achievements for home greenhouses have come in the last 40 years. Today, about 1,500 people are members of the Hobby Greenhouse Association, a group that provides enthusiasts with advice on the upkeep of home greenhouses. If you are thinking about constructing and maintaining a greenhouse in your own backyard --whether it be to have fresh vegetables year-round or simply because gardening is your passion -- here are some things to consider: TYPES OF GREENHOUSES Keepers of a hot greenhouse should maintain a temperature of at least 65 F, ideal for tropical or exotic plants. The temperature remains about 55 F in a warm greenhouse, which is perfect for growing flowers such as sunflowers or vegetables such as lettuce that you would normally plant outdoors. In other words, this type of greenhouse is the right investment for those who want to protect their outdoor gardens in the winter months. In a cold greenhouse, the temperature should be between 40 and 45 degrees. This climate is best for growing seedlings, which rarely require lots of heat and is a great place to get a jump-start on summer gardens, including coveted tomatoes, a plant that is often hard to grow. Plant databases and encyclopedias are excellent research tools that can help you decide which plants would grow best in each type of greenhouses. BUILDING YOUR GREENHOUSE After you have decided what type of greenhouse you will have, you need to start planning its location. Pay attention to the parts of your backyard that get maximum amounts of sunlight during the day. Greenhouses should receive at least six hours of direct sunlight a day, but you can supplement light with lamps if necessary, especially during winter's shorter days. Check with experts at a nursery, garden center or commercial greenhouse for advice on what type of supplemental light will serve your needs. (It varies, depending on the types of plants you are growing.) Also, consider the design of your greenhouse. For example, if you live in a snowy climate, you will have to build a house with an arched, rounded roof that forces the precipitation to the ground. Mounds of snow piled on top of the greenhouse could cause structural damage and reduce the temperature inside. You also have to decide if you want a freestanding greenhouse that is separate from your home or one that is attached. Its really a matter of personal taste and, again, depends on your reasons for building a greenhouse. Consult greenhouse experts and think about all of your options. When building a greenhouse, you can use foam or rigid board insulation in the foundation to prevent the freezing ground below from affecting the temperature inside. This will help lower heating costs. MAINTAINING YOUR GREENHOUSE The fun begins once your greenhouse is up and running. The key to success is paying attention to your plants. Always keep the temperature constant, and water and fertilize plants as directed. Be aware of each plant's maintenance needs. For example, a rare orchid or African violet probably will require more attention than an onion or daisy. Remember, as a greenhouse keeper, green is now your signature colour. Wear it well.