Hobby Greenhouses

Wednesday, 21 October 2009 | Tags: , ,

There's nothing like cooking and eating fresh produce straight from the garden. With backyard vegetable gardens regaining popularity, small, affordable greenhouses are too. We find out which ones are easiest to put up and use, and which ones grow our veggies the best.

The Basics

  • For hobby gardeners, full-size, pre-fabricated greenhouses are widely available and range in price from a few hundred to a few thousand dollars.

  • In some of the fancier models it’s possible to control many of the conditions (heat, light, nutrients, water, and ventilation) 24/7, year round.

  • There are a couple of different model styles to choose from:

    • Free-standing structures receive light on all sides.

    • Add-on structures are attached to your home or garage, which can make it easier to heat and power them.

    • Balcony-size greenhouses are also available for smaller spaces. They’re sometimes called “grow racks”.

  • Temperature plays a role in design as well. Some structures are referred to as cool, warm, or hot, depending on their ability to retain heat.

    • Most balcony-size greenhouses are cool models, claiming only frost-resistance, since their materials are more lightweight.

  • The frame material can make a difference to cost, durability, and effectiveness.

    • Aluminum doesn’t rust and stands up well to weather. It’s not super strong so can’t support larger structures or withstand powerful wind without major reinforcement. The consensus among gardening experts is that aluminum is the best all-around frame material for balancing durability and price.

    • Galvanized steel is very strong, which allows the pieces to be narrower than aluminum, and thus more light can get in. The galvanized coating resists rust, but it can wear off.

    • Wood is strong and provides better insulating qualities than aluminum or steel, but it is prone to warping and rot and can harbor insects and mold. It is also more expensive than steel or aluminum. Pressure-treated wood stands up better but the harmful chemicals can leech into the environment and damage plants. Cedar is your best option since it is strong and resists rot. Wood is higher maintenance too because it needs to be stained or painted regularly.

    • Plastic offers good insulation too and is pretty affordable. However, it’s not very strong and can warp in hot weather. Look for plastic that is light-coloured, so that it absorbs less heat and is less prone to warping.

  • The siding material also affects cost, durability, and effectiveness. Whatever material you choose, look for the thickest possible for durability, heat retention, and light diffusion:

    • Glass looks beautiful but doesn’t retain heat very well unless it is double- or triple-walled (rarely available in hobby greenhouses). Glass may also cause plants to burn since it can magnify light rather than diffusing it. Since glass is heavy, it requires a heavy frame with small panes. And of course, it’s breakable.

    • Polycarbonate plastic is durable and offers good heat retention and light diffusion. Available in single-, double-, and triple-wall thickness, it can last about 20 years before needing replacement. Most experts agree that polycarbonate is the best all-around material.

    • Polyethylene film provides light diffusion but doesn’t retain heat well. However, it is very affordable. If you live in a mild climate or just want to grow in the warmer months, this might work well for your needs. It should last a few seasons before it needs to be replaced.

    • PVC (vinyl) and fibreglass siding are less commonly available. PVC works similar to polyethylene film and fibreglass is like polycarbonate plastic.

  • Siding with UV protection helps protect plants, and also stops the siding from yellowing or losing clarity, which affects the amount of heat and light plants receive.

  • Shelves are a handy feature. Ideally, they should be adjustable to give you more options for the number and types of plants you can grow.

  • Built-in vents cool plants in summer and provide air circulation. They should be easy to open and tightly sealed when closed. Most vents aren’t screened, so you may want to make custom screens for them to keep bugs out.

  • The greenhouse design should allow you to reach all inner areas without awkwardness. Check that seals on doors and any other openings are tight.

  • Choose the biggest greenhouse your space and budget allows for the most growing flexibility.

  • Look for greenhouses that have a small footprint, while maximizing vertical space.

Other Considerations

  • You may want to add a few accessories to your greenhouse, including:

    • A thermometer to make sure you’re plants are thriving under the right temperature.

    • Portable heaters (electric or gas) to use overnight or during cold conditions. Most greenhouses, however, don’t retain heat very well so you may use a lot of electricity or fuel. Electric heating mats sit under plant pots and are an alternative to air heaters.

    • A shade cloth will help keep the greenhouse from overheating in the summer months.

    • Biodegradable soap to clean the surfaces every few months and prevent bacteria and mold growth.

  • Greenhouse placement is important:

    • Set it up in an area where it can receive the most hours of sunlight possible. For a balcony, you’ll need to work with what you’ve got, but 6 hours of direct sunlight everyday is optimal, including during winter.

    • If you are concerned your plants don’t get enough sunlight, grow lights are available at garden supply stores.


To find out which hobby greenhouse is the best, we assembled three different types and grew peas in each one.

  • Planthouse 3′ by Flowerhouse (pop-up model with polyethylene film): $83

. .

(ships to Canada)

  • Deluxe Lean-to Greenhouse by Palram (polycarbonate plastic with aluminum frame): $379
. . Home Depot Amazon.com
  • Wall Garden by Halls Greenhouses UK (glass with aluminum frame): $600
. .

(Note: prices listed above are approximate and in Canadian dollars)

Assembly Test

  • The Planthouse 3 took only a few minutes to assemble. It popped up like a tent. Very easy. It was quite small, however, compared to the others.

  • The Wall Garden glass greenhouse was really hard to assemble. The instructions were unclear and the pieces weren’t marked very well. We wanted to give up on that one!

  • The Deluxe Lean-to plastic greenhouse was a similar design to the glass one, but much easier and faster to assemble. It looked nicer than the glass one too.

Grow Test

We put some pea sprouts in each greenhouse. After two weeks, we compared the results:

  • The ones in the Planthouse 3 seemed to be growing the fastest.

  • The peas in the Deluxe Lean-to were smallest, and the ones in the Wall Garden were in-between.


We really liked the easy assembly of the Planthouse 3 pop-up greenhouse, but it was small, which doesn’t give you much room to grow. It would be great for a small space.

The Deluxe Lean-to Greenhouse by Palram wins out over the Wall Garden due to its much easier assembly.


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