Have you been thinking about choosing a greenhouse to extend your growing season?
You’ve been growing some of your own vegetables for a while, enjoying the fresh taste of home-grown organic foods. Now you’d like to have a way to grow fresh lettuce, chard, peas and other favourites in colder months. And a greenhouse will give you a head start in spring, allowing you to start your seedlings in a protected environment.
One of the major decisions a gardener makes is that of building or buying a greenhouse. Since this can be a major expense, it is vital to explore all the options available. After all, you will have to live with your decision for a long time!
Here are seven questions to ask before you decide on the type of greenhouse you will buy or build.
What is the right type for me?
Both lean-to and free standing greenhouses have advantages and drawbacks. Free standing types allow the best light transmission and ventilation. Choose this type if you have no available wall space to attach the greenhouse to. Bringing in electrical and water connections take more work (and money) with a free-standing unit.
Lean-to greenhouses avoid these problems since utility connections are nearby. Another benefit is the wall will trap heat, an advantage in winter. Lean-to greenhouses generally let in less light throughout the day, unless they are attached to a south-facing wall. However in summer, ventilation and heat build up can be difficult to control.
Are you looking for ways to extend the growing season within your raised bed garden? Simple hoop style coverings (see video below) will be the best choice. A hoop style cover on a raised bed will allow you to harvest many greens throughout the colder months.
Or perhaps you are a patio or balcony gardener. All you need is a small greenhouse that allows just the right amount of sun and moisture to come in while keeping insects and bad weather away from a few plants.
Is it right for the uses I have in mind?
This is the most important question to answer before you commit to choosing a greenhouse.
If you’re planning to concentrate on growing tall plants like tomatoes and cucumbers, then you will require a greenhouse with tall sides and top to bottom glass or clear plastic. If you are planning to use it in winter, then sloping sides will be warmer when the sun is low. Partly insulated solid sides will also reduce fuel costs.
Perhaps you’d like to grow lettuce, herbs, and other greens throughout the cooler months. Or you need protection from wind, sudden frosts, and wet weather in spring while you’re starting your plants.
A smaller greenhouse like the one to the right could fit both those needs, and has the added benefit of being easily dismantled when it is no longer needed.
What is the right size?
You don’t want a greenhouse with too much space for you to fill, or one that is too small for what you would like to grow in it. Do you plan to grow vegetables in it for two people or a large family? Think about what you want it to do for you, and how much space that will take, and then go one size larger.
Will it be tall enough for you to work comfortably? Is there sufficient room for benches to hold smaller plants and trays or flats for seed starting? If you want to include a border bed, can you wheel in a wheelbarrow or garden cart?
Do I care about appearance?
Appearance can be important, especially if your greenhouse is attached to your home or garage. Wood has a more traditional appeal than aluminum, and domed roofs may appeal to you more than a sloped one. Will you use plastic sheeting, fibreglass, plexiglass or glass to let in light? Plexiglass will scratch and look dull over time and fibreglass panels are not as attractive.
A prefabricated corrugated fiberglass greenhouse is very practical and durable but less appealing aesthetically. Its strength is beneficial if you’re located in climates with high winds or heavy snows. The downside is that it can be hard to clean, will yellow with time, and the dirtier it gets, the less light it lets in.
If appearance is secondary to usefulness (and it should be), a hoop style greenhouse made with plastic pipe and heavy plastic sheeting could be a good choice. It can be easily constructed any size you want, is very inexpensive, ane simple to construct.
Is it soundly made?
A low priced model may not be top quality construction. Do the ventilators and door open and close properly? Is the ridge bar strong and steady? Is the glazing properly installed and weatherproofed? What will you require for a floor or for footings?
If you decide to build your own greenhouse, there are several YouTube videos to give you ideas. Search YouTube for “build a greenhouse”, and you will find videos for building a variety of greenhouse types: lean-to, freestanding, hoop style and raised-bed hoop tunnels.
When building a greenhouse, use quality materials and construction.
The flooring must discourage pests, weeds and disease pathogens. Use gravel or duckboards to set containers on so water can drain away. Slatted wood staging is the best choice so air can circulate around any containers, and should be moveable.
What essentials are included in the price?
Make sure you understand what is optional and what is included in the price if you decide to buy a greenhouse. Benches, automatic opening ventilators and the best type of glazing may not be included and can cost extra. What about delivery and charges for erection of the greenhouse? What will it cost to install water, a potting sink, and electricity and fixtures for supplementing the natural light or cool-season heating?
If you’re building your own, check on costs for supplemental items like ventilating windows, heating, and shelving.
Can I afford it?
Consider making your own greenhouse – it may be much less expensive. A simple hoop style greenhouse that has heavy (6 mil) clear plastic stretched over it may be all you need, and is very inexpensive to build. You can even build it over an existing raised bed. Here’s how:
In general, you get what you pay for when choosing a greenhouse.
Scrutinize bargain offers carefully. If money is no object, then you may want to consider double glazed panels and hardwood framing. The most economical and useful commercial choice is probably an aluminum framed house with glass, purchased from a reputable supplier.
False economy of thin plastic on a hoop style house or bed cover will reduce the initial price but cost more in the long run as it will likely need replacing in a couple of years.
Once you’ve answered these seven questions before choosing a greenhouse, your choice will be much clearer. A functional greenhouse is a great addition to extend your growing season, start plants, and protect from inclement weather.
So go ahead and choose the best greenhouse for you – you and your plants will be happy you did.