Neighbours talking over the garden gate has long been a tradition. They share gardening tips, complain about the weather and pests yet are ever eager to discuss their gardens. That is what I had in mind when creating this blog. So stop by my garden gate to find out the latest happenings in my garden.

Happy Gardening!

Garden Gnome
"All my life through, the new sights of Nature made me rejoice like a child." ~ Madame Marie Curie"

Sunday, August 30, 2009

Continuous Harvest

Commercial Greenhouses
August 29, 2009

The idea of growing edible plants indoors is not a new one. Archaeological excavations of Pompeii (79 AD) uncovered the remains of early greenhouses so they have been in use since at least that time if not earlier. The ancient Romans ensured the survival of vegetables and grapes by using greenhouses to protect produce from in-climate weather. They were the early versions of the modern greenhouse. Modern greenhouses originated in Italy in the thirteenth century as a way to study, keep and propagate exotic plants brought back to Europe in early plant hunting expeditions. Greenhouses and conservatories were first used to grow plants indoors throughout inclement weather have been used in Europe for thousands of years.

Commercial greenhouses have been used for decades to grow both edible and not edible plants year round. During the winter months one of our favourite pass-times is to visit Colasanti's Tropical Gardens in Kingsville, Ontario. Strolling through their large greenhouses filled with beautiful plants on a snowy winter's day is simply delightful. Other large commercial greenhouse operations along the Talbot Trail running from Windsor, Ontario through the Niagara region ending in Fort Erie, Ontario grow hot house tomatoes, various peppers and cucumbers for a continuous supply of Ontario produce for consumers. In recent years more and more farmland in southern Ontario is being turned into large commercial greenhouse operations.

On a smaller scale many Canadian universities and schools have greenhouses and/or solariums or atriums. Many home gardeners have hobby greenhouses and/or solariums to help extend the growing season. Solariums have become a popular addition for many home owners because they provide free heat on sunny days as well as create perfect a growing space for growing plants. Home gardeners whether or not they have a greenhouse or solarium still bring in plants when frost threatens. Plants are over-wintered to be replanted in the garden the following spring. Typically these plants include ornamentals like geraniums and annual herbs. A growing trend to compliment over-wintering is to specifically plant fruits and vegetables in containers to be grown indoors.

Basically a modified garden is sown and grown indoors during the winter months. I recently showed how to root tomatoes (more here) for growing indoors. Most herbs, strawberries, peppers, tomatoes, potatoes, carrots, lettuces, chards, radishes, beans and even zucchini can be grown indoors. Aside of providing fresh fruit, vegetables and herbs during the winter months there are other benefits to growing edible plants indoors.
  • Growing indoors eliminates many pest related problems. You don't have to worry about waking up to find deer stripped your garden or the rabbits got your beans. For the most part you should not have to worry about any insect problems if you are careful to quarantine any plants brought inside from the garden
  • Many environmental factors that affect gardening are eliminated when growing indoors. These include not having to worry about: damaging winds, drought, excessive heat, unexpected frost, torrential rains.
  • In most cases plant diseases should not be a problem when growing indoors.
Growing fruits and vegetables indoors presents a few extra considerations. Just like growing outdoors plants need suitable growing conditions. When growing indoors you need to mimic these conditions with respect to water and light. You may need to supplement natural light with grow lights and use self watering containers especially if you will be away for a few days. If you are going to be away for a few days you will not be able to turn the heat down to 10ºC (50ºF) for those heat loving plants like tomatoes. In addition to those conditions many homes that are heated during the winter months are drier so you may have to increase the humidity level in your home for healthy plant growth. Fruits and vegetables growing indoors are grown in containers so you will need to use an organic fertilizer for healthy growth. You will also have to manually pollinate your plants when growing indoors.

Although growing fruits and vegetables indoors presents few problems when the growing conditions are met, there can be a few secondary problems. All soils contain mould spores. Some individuals are sensitive or allergic to moulds so to lessen the impact use sterilized potting mixtures or soil-free potting mixtures. Hydroponics is an ideal solution to growing indoors without using soil. Any damaged or decaying plant material should be removed immediately. As with growing outdoors always do a clean pick removing all ripe fruit or vegetables daily.

Happy Gardening!

Garden Gnome


  1. I've been fascinated by using greenhouses, with little or no heat, to extend the harvest. I reviewed The Winter Harvest Handbook for Gaiatribe and that was just awesome, all the little details.

  2. Given the soggy summer we've had here in New England, greenhouses would serve to keep the rain off the plants.
    Thanks for writing such interesting articles.

  3. Hi Elizabeth and thanks for visiting. It really does depend on your hardiness zone as far as keeping a greenhouse going without heat. I found that it needed at least a high wattage light bulb to keep from freezing. I'm in Canadian Zone 6A so my way to extend the harvest is to grow indoors year round.

  4. You're welcome Margaret. Definitely too much rain can be a problem and this year has been so wet!


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