Greenhouse: Definition, Uses, Types, How it Works

One of the most popular types of gardening is greenhouse gardening. It is a popular method of growing crops all year. Its primary purpose is to extend crop growing seasons by controlling the external environment. The greenhouse is not a new concept, with roots dating back to Roman times. Because Roman emperor Tiberius ate cucumber every day, Roman gardeners had to devise artificial methods, similar to the current greenhouse system, to grow the vegetable year-round.

With time, the concept gained traction and was gradually adopted worldwide. Growing medicinal plants in the greenhouse became popular in Europe in the 17th century, particularly in the Netherlands and England. And America saw its emergence during the 1700s, with the first American greenhouse in 1737.

In this blog, we will be covering everything you need to know about greenhouses. You can use this post as a Greenhouse Hub article to understand the concept and its associated facts better.

What is a Greenhouse?

What is a Greenhouse?

A Greenhouse is a structure in which the external temperature can be controlled to create an environment that aids crop growth all year. A greenhouse is made of transparent materials, such as glass, so that the interior can be exposed to sunlight. The constant exposure to sunlight creates a warmer environment, allowing crops to thrive in cold weather.

One question that may trigger your mind is why a greenhouse is called a greenhouse? 

Greenhouses were originally called “botanical gardens,” but they were renamed greenhouses because, like earth’s greenhouse effects, these gardens absorbed the sun’s light and heat to keep themselves warm and help plants thrive. 

Let’s explain it a bit.

Solar radiation enters the greenhouses through the transparent roof and walls and is absorbed by the surface, soil, and belongings. As a result, the interior climate heats up. The warmed air cannot escape via airflow because the setup is not open to the atmosphere. 

Hence, the temperature inside the greenhouse surges. However, do not assume that greenhouses have no ventilation or windows. In fact, windows must be installed in greenhouses when the temperature becomes too high for the crops within it.

How Does a Greenhouse Work?

How Does a Greenhouse Work?

After exploring the concept of the greenhouse, it is now time to understand exactly how a greenhouse works. The following steps will help in deciphering.

  • Incoming Sunlight: The primary goal of building a greenhouse is to create a controlled environment in which plants can grow. The first step in carrying out the process is allowing sunlight and heat to pass through inside.
    Transparent materials such as plastic and glass construct greenhouse roofs and walls. It is a transparent structure that allows sunlight to filter through and exposes the plants to heat and light during the day.
  • Absorption of Heat: The inbound sunlight is then soaked up by the greenhouse structure, its components, and the plants, converting it to infrared energy, also known as heat.
  • Trapping of Heat: Light’s wavelength changes when it converts to heat. According to experts, it becomes impossible for the changed (heat) wavelength to escape out of the greenhouse’s glass or plastic walls. Because of the structure’s enclosed design, heat is trapped inside and elevates the internal temperatures of the greenhouse.
  • Insulation: Because a greenhouse is nearly airtight, heat is trapped easily, and an increased temperature is maintained inside. Consider getting inside a car parked in the sun for an extended period to get a perspective. Isn’t it going to be a toasty ambiance inside the car?
  • Ventilation: The operation of a greenhouse does not end with insulation; ventilation is also essential. The interior of the structure may become much hotter than expected at times. So, what should you do? In addition to installing windows, we’d need a very good ventilation system in the greenhouse. The greenhouse’s excessive temperature can only be reduced by allowing heat to pass through windows, ventilators, or doors.

    Ventilation aids in controlling the humidity as well as airflow inside the greenhouse.

    The question now is, how does a greenhouse function when there is no sunlight?

    A greenhouse’s glass or plastic structure works perfectly as long as the sun shines brightly. However, these materials are not very good at retaining heat for an extended period. If there is no constant heat or light source, the heat will eventually escape into the outside atmosphere. In such a case, the only way to keep the greenhouse warm is to install artificial heat and light sources, such as LED lights, or work out during the day to trap the excess heat.

What is a Greenhouse Used For?

What is a Greenhouse Used For?

Home gardeners, commercial gardeners, botanists, and commercial plant growers use greenhouses. But what exactly is the purpose(s) of a greenhouse?

Although different gardeners use a greenhouse for different purposes, its sole purpose is to facilitate crop and plant growth all year. At times, it may appear that we are deviating from the natural system of cultivation or growing plants by using a greenhouse. However, this science has opened up new avenues in the gardening world.

  • Greenhouses provide plants a head start, allowing for an earlier harvest. Gardeners who want to grow tomatoes, peppers, and chilies will benefit the most from a greenhouse. Although these plants can be grown outside, a greenhouse has a significant advantage.
  • The greenhouse’s heat can be used for a variety of purposes. You can, for example, use the heat to warm your seed potting mix before planting seeds. This can hasten the sprouting of the seeds. The greenhouse heat can also dry garlic, onions, and other spices and herbs before storing them.
  • Your greenhouse can serve as an oasis in your garden. More than science, it is about a love of growing and cultivating various plants. Along with protecting your plants from the elements, the greenhouse can be a relaxing place to spend alone while surrounded by greenery.
  • You can grow all of your vegetables, spices, and fruits in a greenhouse while also lowering your carbon footprint. You can grow your plants organically, which increases their intrinsic value and their health advantages.

Types of Greenhouses

Types of Greenhouses

There is a wide range of greenhouses available. However, which one is best for you will depend on your intended use of the greenhouse. Here is a list of the different types of greenhouses available for your reference.

Greenhouse Categorization Based on Shape

Shape

Greenhouses are categorized according to their shape or layout.

1. Lean-to Grennhouse

Lean-to greenhouses are most prevalent among hobbyists and are best to construct when the greenhouse is positioned against the wall of an old house. These types make use of the existing building on one or more sides.

2. Even span Greenhouse

Even-span structures are comprehensive structures that are used for modest greenhouses. These types are constructed on level ground and can accommodate two or three rows of plants. However, this shape is not very useful for large-scale commercial gardening.

3. Uneven span Greenhouse

As the name implies, uneven spans are best suited to hilly terrain. The uneven width of the roofs is ideal for accommodating hill slopes.

4. Ridge and Furrow Greenhouse

This design employs two or more A-frame greenhouses linked along the span of the eave.

5. Sawtooth Greenhouse

Much similar to the ridge and furrow type, this shape the facility of natural ventilation.

6. Quonset Greenhouse

This type of greenhouse has pipe arches or trusses supported by pipe purling running along the length of the structure. Quonset greenhouse covers are mainly formed of polyethylene and are less costly than gutter-connected greenhouses.

Greenhouse Categorization Based on Temperature

Temperature based greenhouses

Depending on the temperature, you can choose any of the following types of greenhouses.

1. Cold House

Cold houses are ideal for areas that experience temperatures below freezing. These greenhouses are used to extend the growing season in the spring by allowing for a head start.

2. Cool House

Cool houses, which are best used in temperatures between 45F and 50F, maintain temperatures above freezing to protect plants that cannot thrive in temperatures below 0F.

3. Hot House

Hot houses are ideal for use in temperatures above 60 degrees Fahrenheit. In addition, these greenhouses are ideal for tropical plants, which require additional heat.

4. Warm House

This type of greenhouse is useful in areas with temperatures around 55 degrees Fahrenheit. Warm houses allow a variety of plants to thrive during the winter months.

Greenhouse Categorization Based on Utility

Utility based greenhouses

Based on the function or utility of the greenhouse, you can choose the one that suits you the most. 

1. Active Heating

Temperatures inside the greenhouse may fall in the absence of sunlight or at night. To protect plants from cold temperatures, an active heating greenhouse can be installed with facilities like double-layer polyethylene, thermal pane glasses, a central heat system, etc.

2. Active Cooling

Reduce greenhouse temperatures when the internal ambiance is overly insulated. There are various heat-reduction facilities in an active cooling greenhouse, such as evaporation cooling pads, fog cooling systems, the ability to open the roof, etc.

Greenhouse Categorization Based on Construction Material

Construction Material based greenhouses

When it comes to building materials, the options are straightforward. Each material would be different in price and have its own set of advantages and disadvantages.

1. Wood

Greenhouses with a span of fewer than 6m are often made of wood. This type of greenhouse is commonly made of pine wood. One disadvantage of this type is that it rots easily.

3. Pipe

Pipes are commonly used as a building material in greenhouses with a span of 12m. In pipe-built greenhouses, trusses are not used.

3. Truss

Truss-framed structures are ideal for larger greenhouses that span more than 15m. Steel or angular irons are used for curved edges, forming a beam that includes purlins, chords, and struts. This is one of the most prevalent greenhouse construction materials.

Greenhouse Categorization Based on Covering Material

Covering material based greenhouses

Covering materials are one of the most important factors to consider while constructing a greenhouse. Here are the options that are available in this context.

1. Glass Greenhouse

Before 1950, the only material used to cover a greenhouse was glass. Glass improves the concentration of interior lighting along with aiding airflow, which lowers interior humidity and helps plants resist disease. Glass covers the majority of the lean-to, span, ridge, and furrow structures.

2. Plastic Greenhouses

Polyester, polyethylene, and polyvinyl chloride are used as cover materials in plastic film greenhouses. Plastic coverings are less expensive and more flexible. Their lifespan, however, is shorter than that of glass coverings. Plastic film coverings are frequently used in Quonset designs.

3. Rigid Panel Greenhouse

Rigid panel greenhouses are a good choice for a strong and long-lasting covering with consistent ambient light. The covering materials, in this case, are polyvinyl chloride rigid panels, fiberglass-reinforced plastic, acrylic, and rigid polycarbonate panels. That being said, one of the main disadvantages of this type of greenhouse is that it is prone to fire risk.

What type of greenhouse you want in your garden will depend on what you want to grow and in what quantity. Having said that, there are different types of crops and plants available to be grown in your greenhouse. Although we often associate greenhouses with tomatoes and chilies, anything from vegetables, fruits, and herbs to flowers can be grown within the structure.

Advantages and Disadvantages of Greenhouse

Advantages and Disadvantages of Greenhouse

The idea of a greenhouse often enthralls gardeners. However, this science is not entirely green, as there are some shades of black, or at the very least, grey. Keeping this in mind, here is a list of potential greenhouse benefits and drawbacks. This list will assist you in determining whether you truly want to pursue this science.

Advantages of a Greenhouse

  • A greenhouse can be used for various purposes, including growing plants and drying produce.
  • It protects the plants from the elements.
  • Plants and seeds should get a head start on growth.
  • There is no need to construct a separate garden shed to store your harvest and gardening equipment.
  • It encourages consistent gardening regardless of the weather.
  • All-season gardening is a possibility.
  • Plants will find refuge from pests and other predators.
  • You can grow exotic flowers, vegetables, herbs, and fruits that would be impossible to grow otherwise.
  • A greenhouse can be your green oasis where you can spend time surrounded by plants.

Disadvantages of a Greenhouse

  • It can be costly to construct.
  • A greenhouse would require time to build and maintain.
  • It may necessitate the installation of additional heating or cooling components, which may incur additional costs.
  • A greenhouse may not be appealing from an aesthetic standpoint.

How to Start a Greenhouse?

How to Start a Greenhouse?

Ready to start your greenhouse? Follow the below steps to help yourself in the process.

  • Measure the area you would need to grow your plants.
  • Select the site to set up your greenhouse. A site closer to your house with a constant water and electricity supply is ideal. 
  • Buy a greenhouse kit. There are many options available in the market at different prices.

Note: Instead of buying a greenhouse kit, you can try DIY to set up your greenhouse.

  • Focus on glazing to let the sunlight and heat filter while keeping the elements out.
  • Invest in accessories like vents, thermostats, fans, tool racks, moisture meters, etc. 
  • Make way for ventilation. Installing vents, windows, or rating fans can be good options. 
  • Keep your garden tools clean and check the plants before bringing them in to keep a check on potential pest infestations.

Greenhouse Gardening Mistakes

Greenhouse Gardening Mistakes

Although starting your own greenhouse is not difficult. However, novice gardeners frequently encounter difficulties when starting. There’s also a chance you’ll make a few mistakes that derail your entire greenhouse project. As a result, it is preferable to be aware of potential errors so that they can be avoided while working.

1. Uncontrolled Temperature

One of the most common fatal mistakes novice gardeners make is failing to monitor the temperature of their greenhouse. During the summer, a temperature of 75-85° F throughout the day and 60-76° F at night is considered suitable for a greenhouse.

However, the ideal temperature would be determined by the season and geography. As a result, it is critical to monitor the greenhouse temperature regularly using a hanging thermometer or digital thermometer with corresponding humidity.

2. Uncontrolled Humidity

A humid environment can encourage molds, fungus, and other parasites in your greenhouse. On the other hand, low humidity will cause your plants to perish from dehydration. Checking the humidity level is therefore critical. In addition, you can install ventilation systems and windows to allow proper airflow and humidity control.

3. No Ventilation

A greenhouse is designed to trap heat inside, but that doesn’t mean no ventilation is necessary. Keep in mind that your plants will die if they are not properly ventilated. Also, the hot air inside can cause your plants to burn. Install roof openings, vents, windows, and even fans to allow air to escape.

4. Wrong Location

Plants require sunlight and heat to survive. However, too much light can cause your prized crops to burn. As a result, a location with no shade may fail your greenhouse project. Therefore, it is preferable to locate your greenhouse near a large tree. On hot summer days, the tree’s shade would provide relief to the inside plants.

5. Overwatering

It is critical to water your plants. However, too much water is likely to kill them. Drip irrigation, according to experts, is the best type for greenhouse plants. To assess your plant’s requirements, you should often water them in the morning and allow them some time to transpire before the heat increases. Checking the soil moisture content with a moisture meter is an excellent way to determine whether the soil is dry enough to re-water.

6. Unmanaged Soil

Another blunder to avoid is failing to manage soil inside your greenhouse. Because you will be growing the same crop in the same location repeatedly, soil depletion is high. Furthermore, the soil may become densely packed, lose fertility, and become a breeding ground for pests.

Hence, when constructing your garden beds and using compost and fertilizers, opt for a blended soil mix. Avoid using old potting soil because it may harbor pests and diseases that harm the plants.

FAQ

These facts and queries will help you to understand in a clear and concise manner about Greenhouse that may have been missed above. 

Do plants grow better in a greenhouse?

Yes, plants grow better in a greenhouse because the greenhouse provides a stabilized environment by controlling the ambient temperature. As a result, plants are protected from freezing temperatures and other elements and thrive better. That said, controlling the greenhouse temperature, humidity, and airflow would directly affect how your plants will grow

What to grow in a greenhouse?

A greenhouse can be used to grow a variety of vegetables, fruits, flowers, and herbs. The following list some of the most common crops grown in a glasshouse or greenhouse.
• Tomato
• Pepper
• Cucumber
• Carrot
• Squash
• Broccoli
• Melon
• Geranium
• Ferns
• Pansies, etc.

Where to put a Greenhouse?

The typical location for a greenhouse should be in the south or southeast direction, where it will receive the most sunlight throughout the fall and winter. If you want to grow crops throughout the year, you can also place your greenhouse on the east side. However, if you want to cultivate summer crops, set up your greenhouse in a north-south direction.

How to pollinate in a greenhouse?

You can pollinate your plants in a greenhouse in a variety of ways.
Manual pollination in a small greenhouse could be accomplished by patting the flowers to allow pollen to be released from male flower parts to female systems. Pollination can also be aided by battery-powered pollinating tools or hand-held pollinator wands. If you have a larger greenhouse, you can also cultivate bumblebees, particularly in your greenhouse.

Do greenhouses work in the winter?

Yes, various plant species can be grown in a greenhouse during the winter months. 

What is a greenhouse made of?

A greenhouse can be constructed and covered with different materials. Usually, glass and plastic are used to make greenhouses. If you wish to learn more, refer to the above section where we discussed different types of greenhouses. 

Conclusion

So that’s our take on greenhouses and greenhouse gardening. If you are interested in greenhouse gardening, this post will provide detailed information. There are numerous reasons why plants should be grown in a greenhouse. And if you’ve made it this far, we assume you’ve determined why you want to build a greenhouse.

This article should have provided you with a wealth of information. We’d love to hear from you if you have greenhouse gardening experience. Please leave a comment below to share your experience.