BUYER’S GUIDE

There are many factors involved in choosing a greenhouse. With all the options available it’s hard to know what you really need. Greenhouses.com is pleased to offer a brief breakdown of “what’s what” to make your decision simpler.

When you are researching the many types of greenhouses available the process may seem a little confusing.

You will need to make several decisions before you are ready to order a greenhouse. Some of these choices are based on money, how much you enjoy gardening, and what type of climate or grow zone you live in. As you start the process, you may want to grab a notebook and take notes as you do your research.

Start like this: Write down three things that you want in your ideal greenhouse. This could include vents, how many doors, how large or what type of plants you want to grow. Measure a room in your home, and compare the measurements to the size of greenhouse you think you'll want. This is an easy way to wrap your head around how much space you'll really have inside a greenhouse. Figure out your budget. Determine the amount of money you are going to spend on this project. If you don't have the budget to fit the type of greenhouse you want to get, you may want to wait a few more months until you can save up what you need. Settling for something cheaper just because you want a greenhouse right away may end up costing you satisfaction and money in the long run. One of the last things you need to figure out before greenhouse shopping is what do you expect the structure to look like.

There are some very simple greenhouses, which do not cost much, but then there are very fancy greenhouses with multiple doors, vents, accessories and decorations that could be just what you have always dreamed of. When you finally find that greenhouse based on your selections of style, function, and price you will be very satisfied with your choice.

Now, if you find you have a little more time, we will break this process down even further:

Six things every potential greenhouse owner should ask themselves before making a purchase are:

What is my budget?
What size do I need?
Does style factor in?
What do I want to use this greenhouse for?
What kind of greenhouse is best for my weather conditions?
Are there any local restrictions or permits needed for home greenhouses in my area?

Some of these questions are easier to answer than others. The need for permits can be resolved with a simple phone call to your local zoning board. You may find you don’t even need a permit, or, you will find out the necessary steps and restrictions to legally build a greenhouse in your yard.

Style is, of course, a matter of taste. But incorporating style into your greenhouse selection is also a matter of funds. If you want to invest in a greenhouse that suits the design of your home or landscaping, or if your desire for a greenhouse leans more toward hosting luncheons than producing fresh tomatoes, you’ll find yourself delving out bigger checks than for a greenhouse bought on function alone. Of course a greenhouse with more architectural flare is more than worthwhile if you can afford it- not only is it aesthetically beautiful, but can add a lot of value to your property.

What size do you need? That depends on a couple things. Such as; budget, purpose, and available space. Knowing how much room you can dedicate to greenhouse space will narrow down your options. You wouldn’t be looking at a 12’x 12’ greenhouse if you only have an 8’x 8’ space! Though it is usually recommended to buy one size up from what you were considering, (in case your passion for greenhouse growing increases with time), we recommend that you do what is right for your budget and space restrictions, but that you do consider getting a greenhouse that is expandable, to alleviate this problem later on, if it arises.

Budget is an incredibly important subject to tackle. Setting your limit beforehand will keep you from getting carried away later on. It is good idea to do a lot of research before making a purchase. You’ll want to know which features you need right away vs. which you can put on hold until funds allow.

Besides knowing what price range is comfortable for you, you’ll also want to do some research into what is desirable for your local environment. If you have harsh winters, you’ll need to invest more of your budget into a sturdier frame, stronger glazing, peaked roof, etc. If you get extremely hot summers and mild winters you may want to look at wood frames which are less costly than some metal frames and do well in dry climates. If you get wet winters you’ll want to invest in a rust-proof aluminum.

If you are going to use your greenhouse to start seedlings, or for extending your growing season, you won’t need a huge structure. In fact you may find contentment with a collapsible or cold frame greenhouse. For growing flowers you’ll want something larger, tightly sealed, with good insulation. If you want to grow fresh fruits and vegetables you’ll need something with lots of space to move around in and extra height for tomatoes, etc., to grow into. Knowing such things ahead of time can really make the process of choosing a greenhouse a lot easier.


MATERIALS

It is difficult to declare one material as more valuable than another. What it really comes down to what is suitable for your area, what you can afford, and personal taste. In fact all types of materials whether aluminum, wood, PVC, polycarbonate, or glass, have advantages and disadvantages that level the playing field. We’ll break these materials down for you to know whether they are right for your needs.


FRAMING

Galvanized steel
Galvanized steel is long lasting and adds permanency to your greenhouse structure. Galvanized steel offers durability against the harshest environments. Unfortunately, though it is strong and reliable, steel framing can be very expensive and is not found in greenhouse kits as often these days due to associated cost. Shipping steel is also costly due to weight.

Plastic or PVC
Plastic or PVC greenhouse framing kits are inexpensive and easy to assemble. With a plastic framed greenhouse, you can move your greenhouse easily if the need arises. If you are considering this type of greenhouse kit you will need to take into account how strong winds are in your area. If you live in a high wind area you might not want to use this framing, or at least will need to anchor it down for support. Plastic bends and breaks when under duress from extreme weather, so it is ideal for milder climates. Plastic framed greenhouses are also a good beginner greenhouse.

Wood
Wood is aesthetically pleasing, especially when combined with glass. It has the added bonus of being a natural insulator as it absorbs heat throughout the day and releases it throughout the night. Unfortunately, wood also absorbs moisture in the air, and will rot faster, requiring more treatment/maintenance than any other framing. Therefore it is ideal for very dry climates.

Aluminum
Aluminum will not rust and can withstand extreme weather. Aluminum framed greenhouses are designed as compatible with a variety of coverings from plastic, to glass, and polycarbonate. The channels in aluminum framing generally include details for you to add accessories to or to hang baskets from. An aluminum framed greenhouse offers ease in assembly for the do-it-yourself gardener.


COVERING

Here is a quick insulation reference guide on the varying thicknesses of different greenhouse coverings:

Covering Insulation (R) Values for Polycarbonate, Polyethylene, Glass, and Fiberglass
Covering Material R Value Covering Material R Value
3 mm Glass (single layer) 0.95 4 mm Twin-wall Polycarbonate 1.43
Two layers of Glass (insulated) 2.00 6 mm Twin-wall Polycarb
1.54
8 mm Twin-wall Polycarb 1.61 4 mm Polyethylene
0.83
10mm Twin-wall Polycarb 1.89 6 mm Poly 0.87
16 mm Triple-wall Polycarb 2.50 6 mm Poly double layer (inflated) 1.43
Fiberglass / Polycarb (single layer) 0.83 11 mm woven Poly 0.95
R value: a unit used to measure the effectiveness of thermal insulation.
A higher insulation value indicates greater heating and cooling efficiency.

Glass
Glass glazing – Glass was considered the standard of covering for greenhouses in earlier years. Glass is heavier than many plastics, and requires a heavier frame; usually wood or steel. The main problem with glass is the breakability factor. If you live in a high wind area or have plenty of children playing around your greenhouse, you will find yourself replacing glass often. Apart from the prospect of breaking, glass can also become brittle with aging.

Rigid plastics / polycarbonates
Rigid plastics are fiberglass, acrylic, or polycarbonate, and come in corrugated or flat sheets. These rigid plastics are shatterproof which is ideal when you have children running through your yard, or if you have rough weather. They offer UV protection, and are lightweight so you can easily use them in conjunction with aluminum framing. Another advantage of rigid plastics is that they retain heat very well.

Polyethylene Film
Due to ease of maintenance, polyethylene film is a first choice amongst commercial growers. Otherwise polyethylene is typically found on cold frames and greenhouses used for season extension/seedling starts because it retains heat better than most other coverings. Beware, though, of cheaper versions of polyethylene film found in most home department stores- this type of film is absolutely not suitable to the needs of even a basic greenhouse.


You may want to look for coverings that offer UV protection for both yourself and your plants inside the greenhouse. This feature has become so popular and innately useful that most coverings already offer it.


LOCATION
So how do you choose a site for your greenhouse? Though placing a greenhouse directly in sun exposure is optimal for many gardeners, it really depends on what you want to use your greenhouse for. You may want to use your greenhouse for starting seedlings or plant propagation; in this case you’ll want to place your greenhouse in partial shade. If such a space is unavailable to you, you can use shade cloths to promote shading.

If you are going to use the greenhouse for growing into the colder season you’ll want maximum sun exposure. A spot with full southern exposure is best for this. Of course if you lack space in a southern exposure you can make up for heat with artificial heating/lighting, though this will be a more expensive solution. A rule of thumb for sun exposure is to secure at least 6 hours of full sunlight a day. Remember to keep in mind that the sun rests in different positions throughout the year. It is higher in the summer than the winter. A spot that seemed perfect in June may be a problem come January.

Try to place the door of your greenhouse in a direction away from which the wind blows. If your wind typically blows up from the south, face the door north to limit breeze entrance and heat loss. Also remember that shadows cast by any trees or buildings around your greenhouse will change throughout the year. Long shadows can mean sun blockage for your greenhouse plants!

You’ll want your greenhouse to be easily accessible through all seasons. You can save your back a lot of stress from carrying soil, water, etc., by making the path to the greenhouse level and short. Make sure that the site you prepare for your greenhouse is also level to prevent stress on the structure and leakage problems.

We hope that this has been helpful for you in making your decision, and hope, also, that you truly enjoy your new greenhouse!


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