Greenhouses allow gardeners to germinate seeds and grow plants before it is safe to plant them in the ground in their area. Greenhouses also allow gardeners to create an environment where they might be able to grow a specific type of plant that might not thrive in their area at any time of the year. The reasons not to have a a greenhouse are the cost to buy or build, space needs and time, energy and money to maintain the building.
Gardeners will spend more money upfront to purchase a prefabricated greenhouse or to build a greenhouse from scratch than they will to plant directly in the ground or containers. It is not unusual for gardeners to spend $1,000 for a small, entry-level greenhouse structure. For a more substantial structure with heating, irrigation and ventilation systems, the price rises considerably. Gardeners, who build their own greenhouses, must pay for construction materials and sometimes, for additional labor. It will cost extra to hire electricians to add electricity for lighting, heating and ventilation units and plumbers to connect pipes for water and drainage. Homeowners will then see an increase in their monthly water and electric bills. In some municipalities, homeowners must pay permit fees, if they are allowed to build at all, to add a greenhouse to their property.
Homeowners need space in their backyards or gardens for the greenhouse. Greenhouses will be more efficient in open locations where they receive natural light, preferably direct sunlight. Ideally, greenhouses will receive light from above and at least one side. Thus, a gardener who purchases a standard 6 x 8 foot greenhouse needs to plan for several more yards of space to surround it. Manufacturers charge more when they add stylish embellishments to a greenhouse. Homeowners, who have the physical space for a greenhouse, may require a particular look to complement their landscape. Other homeowners may not want their view blocked by a building, even one with mostly translucent to transparent sides. A greenhouse placed near a property line risks reducing light on a neighbor's property and that may cause unexpected problems.
Homeowners must expend time and money to maintain greenhouses by adding insulation when necessary. Most manufacturers of lower-cost greenhouses do not insulate them well enough to protect the plants against strong winds or cold temperatures. Gardeners must caulk around windows and doors, as well as, add layers of plastic to keep heat in during the winter.
Greenhouses need ventilation to release the excess hot air that builds up. Greenhouse owners will need to install an automated vent system or spend time measuring the interior temperatures of the greenhouse and then opening windows or doors, manually, to release the heat.
Lots of light and humidity help plants to grow, but these conditions also encourage the growth of algae and fungi and greenhouse owners must clean this from the roof and wall panels on a regular basis.
One winter snowstorm can deposit heavy snow on the roof and cause the roof or the entire structure to collapse. Greenhouse owners will have to devise some strategy to clear the snow off the roof and that usually entails standing in the cold.