Home & Design July 24, 2008
Greenhouses
Indoor Growing

A greenhouse may be as grand as a summer palace or as plain as a muddy old shoe. It may be an architect’s dream of Victorian splendor, a homely Quonset hut or just pieced-together plastic and wire.

The elegant ones are often called “conservatories,” and are frequently given over to the cities where they are built to become educational facilities, though not always. And the plain ones serve to gladden the heart of only the gardener who tends them.

Greenhouses are ultimately democratic, for the same sun beats on them whether they are beautiful or ordinary and the same mice attempt to wiggle in to snack on the botanical products inside.

There are many companies that will sell you plans for greenhouses, including one from the UK that asks: “What could be nicer than picking your own lemons or grapes, or sitting in the shade of an enormous passionflower.”

Well, put that way, how could you not want a greenhouse?

Hollywood has used greenhouses in many films—there’s something inspiring about all that glass to break—usually portraying the avid gardener as eccentric (think Katherine Hepburn potting a plant and giving sage advice) or murderous (think any number of scary movies) or a great place to hide booze (think Days of Wine and Roses.) But truth be told, greenhouses are usually tended by nice people who like flowers and vegetables (OK, there was the rich man in St. Louis who filled his tall greenhouse with exotic birds and big plants and was said to have a giraffe in the mix until city fathers cracked down on him.)

But whether you favor a greenhouse palace or a very simple shelter, whether you want to grow hothouse flowers or vegetables, your greenhouse can make you happy year-round.

Idaho’s famed professional “farmgirl” Mary Jane Butters, who runs an organic operation in Moscow, writes in her Mary Jane’s Ideabook Cookbook Lifebook, “You could be supplying your family’s daily quota of winter greens from September through May nonstop, without ever going to the grocery store. All you need is a simple unheated plastic hoop-house and a selection of frost-tolerant seed.”

There’s plenty of free advice for do-it-yourself types on the Internet, as well.Beyond what you can grow, gardening is good for you and good for others. A national program called Greenhouse Grants provides greenhouses to facilities that use horticulture as a treatment in working with older adults, families at risk, abused children, and people with physical or mental disabilities. The foundation was started by a family as a way to remember a lost son.

Beyond the therapeutic values, some use greenhouses to provide produce to sell at local farmer’s markets. So you could grow your own greens, or fill your greenhouse with flowers. As one greenhouse fan rhapsodized in The New York Times: On a gray cold winter day you can fling open that greenhouse door and be enveloped by the brilliant colors and scents of  summer. >>>

 
Questions and Answers:

Question:
What is a greenhouse and what is the purpose of a greenhouse?

Answer:
Greenhouse construction for sustenance is growing.Utilizing the greenhouse concept and understanding our climate allows us to create micro environments in which plants generate. A simple greenhouse may be a “grow hole” that is excavated a few feet into the earth, partially filled with compost, planted, and covered with a glazing material. Glazing material is typically glass or plastic. Cold Frame greenhouses are constructed tents or framed boxes of glazing material. They are placed over a section of plants in the garden, and the design allows them to be removed or replaced as weather presents itself.
—John Benson, Webb Landscaping

Question:

Are greenhouses for keeping plants in forever or is the object to get them moved outside?

Answer:
Some tropical plants may stay in the greenhouse for their entire life, but the general objective is to move plants outside. Most homeowners use their greenhouse to extend the season, to get an early start or to extend it in the fall, or both. They start bedding plants and veggies early from seeds, and when the weather is warm enough they move them outside.
—Sun Valley Garden Center Staff

Question:
How do you help plants cope with the transition from greenhouse to garden?

Answer:
They need to be hardened off by moving them into the great outdoors when the weather is warm for quite a few consecutive days and generally the danger of frost has passed. They should be kept in a protected area out of direct sunlight where their leaf and stem tissue can toughen up. Outside temperatures, especially nighttime temps, need to be watched during the entire season, since frost is often just around the corner. Greenhouses can also be used to extend the season in the fall if you move container grown plants into your greenhouse before the first frost.
—Sun Valley Garden Center Staff

Question:
How do you maintain the humidity inside a greenhouse and how does that intermingle with how you feed plants?

Answer:
When I water, I am not careful at all. I spill it over onto the heated brick floor, which holds water. You don’t want your plants in standing water, so don’t use any trays under them. But with the running water, some plants get an iron deficiency. If the leaves turn yellow, you need to add iron to the soil. I fertilize in the fall, and then give them a rest and then hit them again in mid-January when the plants appear to be booting up for spring. Plants go on the length of light to determine if it’s time to fruit or blossom and that’s when I fertilize. You learn how to feed each one by touching the soil and checking the leaves. Most plants will show neglect after three days without water. When it’s time to take them out, I tend to choose a cloudy day so they don’t burn up.
—Lynn Clarke, master gardener and designer of large gardens and greenhouses

Question:
How is the warmth of a greenhouse generated?

Answer:
In our climate, constructing greenhouses and incorporating solar greenhouse design ideas is beneficial because they:
    • Have glazing oriented to receive maximum solar heat during the winter.
    • Use heat sinking/storing materials to retain solar heat.
    • Have large amounts of insulation where there is little or no direct sunlight.
    • Use  glazing material and glazing installation methods that minimize heat loss.
    • Rely primarily on natural ventilation for summer cooling.
– John Benson, Webb Landscaping

Question:
How do you keep the delicate balance between good bugs and bad in your greenhouse?

Answer:
 I have trouble with scale, mealy bugs and sometimes aphids. Spiders are your friend. The greenhouse is where all the bugs want to live because it is warm and attractive, but in one of our green houses we have finches and a frog and so we use organic sprays for insect control. Just before I bring the plants in for the fall, I will wash the leaves with soapy water to wash off any larvae and then spray them with dormant oil. There are systemic control methods that go into the roots and make the leaves toxic, but you can’t use that on a lemon tree because you want to use the lemons. If you get a plant with aphids, put some plastic over it so it doesn’t leave a trail on the way out and throw it away. These will explode on the environment and it’s better just to get another plant. Just preen and look over your plants and look for trouble spots. I wash the leaves weekly. You also should know if you have self-pollinators or plants like tomatoes that will need a little help because for the most part, this is a sterile environment. But try everything. It’s the only way to learn.
—Lynn Clarke, master gardener and designer of large gardens and greenhouses

This article appears in the Spring 2008 Issue of Sun Valley Magazine.