Making a Selection - Types of Greenhouses
Once you’ve determined the size green house you can accommidate, afford and where you’ll put it, it’s time to consider the type of greenhouse you will build. There are a few options available for hobby green house gardeners.

Once you’ve determined the size green house you can accommidate, afford and where you’ll put it, it’s time to consider the type of greenhouse you will build. There are a few options available for hobby green house gardeners.

The two primary categories green houses fall under are attached and freestanding. Attached type green house includes window-mounted, even-span and lean-to. Attached green house are meant to be attached or housed on a supporting structure like a dedicated wall on your house or building.

Freestanding greenhouses, as the name implies are freestanding structures that do not require a supporting wall or building.

Types of Greenhouses
If you remember from our previous lesson (Introduction - How to Build a Greenhouse), greenhouses fall under two primary categories: Attached and Freestanding.

Attached type green house includes window-mounted, even-span and lean-to. Attached green house are meant to be attached or housed on a supporting structure like a dedicated wall on your house or building. Let’s look at each type of greenhouse in a bit more details.

Attached Greenhouses
There are several types of attached green houses to choose from. Types of attached greenhouses includes Even-Span, Lean-To and Window-Mounted.

• Even-Span Greenhouse
  An even-span greenhouse is generally the most costly as well as the largest attached structure available. Even-span greenhouses is generally more capable of holding more plants because of the larger space and can be extended. The shape of the even-span greenhouse offers better air circulation for a more uniform temperature. An even-span greenhouse is capable of holding up to three benches for cultivating crops.
  
  

• Lean-To Greenhouse
  A lean-to green house is a good choice for gardeners who have limited space. The lean-to green house looks like a greenhouse split in half along the ridge line. Another good reason to select a lean-to green house is that it’s accessible and close to external requirements like electricity and irrigation supply.
  
  Lean-to green houses do have some disadvantages, most notably, the size limitation, available sunlight, controlling temperature and ventilating the structure. It may be difficult to ventilate the lean-to because the supporting structure may absorb excessive heat while the translucent cover allows heat to escape at a rapid rate.
  
  The size of the supporting structure used to hold the lean-to green house in place will determine the size of the greenhouse. The supporting structure also limit the availability of sunlight to one side of the green house. Lean-to greenhouse should be placed in a spot that receives plenty of sunlight. The location of the windows and doors should be planned carefully.
  
  Lastly, you should scrutinize your selected green house location signs of trouble like areas prone to snow or ice sliding from the roof on to the greenhouse, breaking the glass or damaging it in some way.
  
  

• Window-Mounted Greenhouse
  Window mounted greenhouses are a glass enclosed space that offers the convenience of owning a small hobby green house at a relatively low start-up cost. Window-Mounted greenhouses are a special window that extend outward from your home by about a foot. Window-Mounted green house can hold two to three shelves for growing crops and should be attached on the south or eastside of a structure.

Freestanding Greenhouse
Unlike attached greenhouses, freestanding greenhouse is capable of standing independently. A support structure like a dedicated wall on your home or building is not required to keep a freestanding green house up-right and in place. Freestanding greenhouse offers the benefits of selecting any location to place your greenhouse. Freestanding greenhouses also allow more sunlight to enter the greenhouse because there’s no obstruction on any side. It can be set in an open area to enjoy full sun exposure all day if desired.

Similar to the even-span, freestanding greenhouse is also the lowest cost per sq ft. of growing space. It can accommodate two side benches, two walkways and a center bench and offers acceptable cost-space ratio.

A potential down side is that a separate temperature control system may be required and electricity and irrigation must be installed (if not accessible).

The temperature in larger greenhouses are easier to manage because in smaller greenhouse, the temperature fluctuate rapidly. Exposed areas in smaller greenhouses causes temperature to change frequently. 6 feet wide by 12 feet long for an even-span or freestanding greenhouse is the minimum recommended size.