How Does A Greenhouse Work?

Updated:

Wikipedia defines a greenhouse as “a structure with walls and roof made chiefly of transparent material, such as glass, in which plants requiring regulated climatic conditions are grown.” And as we know, in gardening, a greenhouse is an essential element for growers and farmers in every part of the world. These structures are used nowadays even in cities and homes with limited space.

Have you ever thought about the mechanics of a greenhouse? — How it works and what goes into creating that ideal environment for plants? That’s what we will discover in this article.

How does a greenhouse work?

We might have studied how greenhouses work in our school days. Maybe vaguely, we remember that a greenhouse allows solar energy in and sustains the environment — but how?

Greenhouse structures work by taking in sunlight and using it for heating. It turns the solar energy of the sunlight into thermal energy. Various materials used in a greenhouse allow full or partial sunlight to filter through the walls and ceilings. This solar energy is absorbed by the vegetables and plants who convert this heat into further energy and warmth. This method is known as convection.

When the heat is expatriated, it becomes trapped in the greenhouse structure which in turn creates humidity. Humidity is the amount of water vapor in the atmosphere and is required for plants to grow well. Hence, this system circulates on its own to create the ideal growing conditions for plants, vegetables, flowers and crops.

Greenhouse
A richly decorated indoor greenhouse

Because greenhouses essentially work on the principal of using warm sunlight or solar energy, they must be erected in hot climates or with structures that can control the temperature.

In colder climates, additional heat ought to be added to keep the greenhouse temperature constant. Farmers use heaters to control the temperature around their plants with climate control systems like the ones mentioned in this article here.

During hotter months, adequate ventilation is installed to allow for air and heat to escape. A good ventilation greenhouse system is crucial to prevent overheating. Some greenhouse growers prefer ventilating naturally by opening the doors and windows of their structures.

Solar greenhouse

Constructed from either glass or plastic, solar greenhouses differ from standard greenhouse structures that absorb solar energy through their plants. Solar greenhouses store solar energy when the sun is not shining. This type of greenhouse is specifically used in the Northern Hemisphere where sunlight exposure may be limited, especially in the colder season.

As passive solar energy is the cheapest and easiest way to maintain consistent heat in a greenhouse structure, many growers are now turning to solar greenhouses. Since passive solar energy heating depends on the sun, it is crucial to ensure the structure receives as much direct solar heating as possible. The south side wall is typically covered in order to maximize solar energy retention. Additionally, the north facing wall may be insulated to sustain heat from escaping. Insulation could be placed over the greenhouse structure during nights and colder seasons to prevent further solar energy loss.

Brick, rocks or concrete on the dark ceramic flooring and northern exposure, will store solar energy for longer. There are also certain plants and crops grown in water-filled containers that can boost the amount of the solar energy retained.

Solar greenhouses can be constructed as attached designs or freestanding models. Attached designs are lean-to greenhouse structures are attached to the walls of a barn or house, thereby forming an extension of the property. These greenhouse structures provide adequate room for kitchen herbs, transplants and other limited quantities of vegetables and plants.

Freestanding solar pit greenhouses are independent entities that have their own spaces large enough for the commercial propagation of vegetables, ornamentals or herbs.

How does a solar greenhouse work?

Solar greenhouses, as their name suggests, utilize energy from the sun in order to meet their temperature needs. The solar radiation from the sun passes through their surfaces to heat the ground. The solar greenhouse design then traps this energy in order to maintain the higher temperature it needs.

The walls and ceiling of these useful structures also prevent the warmer air within from mixing with the cooler air. A more technical way of saying this is that they prevent convection (heat transfer through moving gas or liquid) and conduction (transmission of heat from particle to particle within solids) from equalizing inner and outer temperatures.

Solar greenhouses will also serve to control internal temperature by controlling the transparency to the solar and terrestrial thermal radiation bands. For a warmer temperature than the surrounding environment, more transparency is presented to the solar radiation band.

At the same time, more resistance to the thermal radiation band serves to trap the heat in the greenhouse. A surface that is more reflective to solar energy while less restrictive to the thermal radiation band will, of course, have the opposite effect — a cooler environment than the sounding temperatures.

Generally, solar greenhouses are utilized for the purpose of creating a warmer environment. For this, a material is chosen which absorbs some of the infrared radiation. A portion of this radiation will be reflected back into the greenhouse.

Another effective aspect of solar greenhouses is the optimized usage of the soil base. A portion of the available heat during the daytime will be absorbed by this mass. At night, this soil becomes a source of radiant heat. Sometimes, installing tubing for subterranean air circulation increases the effect of heat retention. While a subterranean design can provide heating at night, it can also encourage cooling during the daytime through this same method of absorption.

Another method of encouraging this same effect of absorption is by utilizing storage materials with a high capacity for heat. Bins of sand and rock or containers of water are such examples.

Solar greenhouses benefit greatly from the newest and latest plastic surfaces and glazing options. With better material and design, a greenhouse owner is better able to control both the wavelengths of incoming solar radiation as well as those of outgoing thermal infrared radiation.

Greenhouse gardening for amateur or beginner-level gardeners

Greenhouse gardening is a satisfying and rewarding endeavor for amateur and professional gardeners alike. These days, there are plenty of options available for beginner gardeners like the use of greenhouse kits and easy-to-assemble hydroponic systems.

Greenhouses for beginner-level gardeners

For many individuals, the idea of starting a greenhouse structure can seem like a difficult job. Remember that a greenhouse structure does not have to be a huge construction project. For many homeowners, a simple and compact greenhouse is enough to meet their needs. Even mini greenhouses on window sills can do the trick.

Greenhouse kits are another option for beginner gardeners to quickly set up greenhouses. These are often available from online retailers and local home improvement shops. It’s crucial to choose the appropriate greenhouse kit for your needs as they come in a variety of sizes and shapes. Check out our list of the most reliable greenhouse kits on Amazon here.

Which are the best plants to grow in a greenhouse?

Tomatoes, onions, peppers, corn, pumpkins, carrots, radishes, greens of many varieties, strawberries, cucumbers and garlic can all easily be grown together in a greenhouse. High amounts of light, humidity, temperature, moisture and fertilizer are all needed to grow healthy plants. Each plant might have slightly different needs. However, one common need for all plants is never to overwater them. That will always do more bad than good. Check out our extensive classification of greenhouse plants based on the type and need in our article here.

Someone with a green thumb and a little experience could turn their amateur greenhouse into a revenue model by specializing in plant products, not just plants. For example, if you find yourself consistently grow amazing garlic, consider specializing in garlic products like garlic powder, rubs and pickles.

There are 5 main things an amateur gardener can do with a greenhouse:

  • Raise winter plants
  • Safely store parent plants for the next season
  • Propagate and experiment with plants
  • Raise a larger variety and a more continuous supply of food bearing plants
  • Easily cultivate of small vegetables for own needs

There are a string of elements to plan out before you choose a greenhouse design and begin the building process, such as:

  1. Planning work requirement — Consider the kind of workspace you will need. Workbenches? Potting shelves? How high? How many? What kind of wood? Sink? Where?
    These are all questions that must be answered before choosing a design. If you plan to use wood to build benches, make sure it is rot-resistant wood. And avoid the pressure-treated wood as it contains highly toxic levels of arsenic and could poison your plants. You can also buy a DIY kit to build your own workbenches as well.
  2. Greenhouse orientation — Another crucial planning element, regardless of the type of greenhouse, is its orientation. Plan to place the structure in a position where there is clearing towards the SE through the SW for as much winter sun as possible. When planning the orientation, take into account the change in the angle of the sun between summer and winter.
    Hint: The sun is at different angles during different seasons. It is most ideal to align the greenhouse with the long side facing south. This accomplishes two things: it reduces the number of sides a shade cloth will have to cover, and also, positions the roof to its maximum sun-hours-per-day position.
  3. Investing in good climate control instruments — Climate control mechanisms like a good, reliable thermometer are also required for greenhouse success. A thermometer lets the greenhouse gardener constantly monitor the structure for temperature variations that could damage plants. It lets you know when to ventilate and keeps track of temperature readings and watering routines and their effects.
  4. Providing adequate lighting — Plants need solar energy whether they grow in the greenhouse garden. A perfect quality full-spectrum fluorescent sunlight is best for the structure. You can also purchase artificial lighting which are almost equal to the light of the sun.
  5. Ensuring proper ventilation — Another of the more basic ideas for working in a greenhouse garden is proper ventilation. It is true that plants and flowers need warm temperatures for good growth; however, a greenhouse garden can often become too warm, which is why greenhouse ventilation is so crucial. Being able to maintain an ample growing temperature will have a positive impact on a greenhouse’s growing capability. The installation of roof and louvered vents will maintain a good flow of air that ought to prevent heat and humidity build up.
  6. Replenish soil nutrients periodically — If you want to grow healthy plants in your greenhouse garden, replenish their nutrients at frequent intervals. Test your greenhouse’s soil annually to maintain the proper levels.

Greenhouse maintenance tips

Every grower has their own unique tips and tricks for working in a greenhouse structure. From what, how, and when to plant, to the “solution” to raising the good tomatoes, the pieces of advice can be endless. There are few common tips, however, that are basic to nearly ever greenhouse structure, like these ones:

Greenhouse

Keep your greenhouse clean

One of the most important ways you can work to keep your greenhouse in tip-top shape is by keeping it clean both on the inside and outside. When you clean your greenhouse can change depending on what you are growing. The general rule is to clean it during the winter or at the beginning of spring. For certain kinds of plants, cleaning it in the middle of autumn is also appropriate.

For the inside of your greenhouse, throw out any debris and organize any empty pots and tools. Then prepare to clean the surfaces in your greenhouse with warm water and a sponge, along with a disinfectant, if you choose to make it sterile. Don’t forget to unplug any electrical elements you might have running in your greenhouse first.

For the outside of your greenhouse, carefully remove any debris around it and use warm water and a sponge to clean the walls. For the roof, a mop with a long handle will help clean the panels. Remember to be careful, never lean against the roof.

Always choose a dry day to clean your greenhouse when you can open all of its windows, vents, and doors.

Look for greenhouse damage

Greenhouse maintenance also involves regularly checking the structure itself to make sure there is no damage. It’s easiest to check for cracks in the glass or possible rot on a wooden frame during your cleaning process. Check often for these signs especially if you’ve experienced a rough winter. Spotting indications of damage early that need to be fixed will help ensure that your plants are in the best and healthiest environment possible for them.

Greenhouse pest control

Pests are unwanted guests for any plant, and they can be detrimental to the garden in your greenhouse. To help retain a pest-free greenhouse, there are many preventative measures you can take like:

  • Watch your plants in your greenhouse carefully for any signs of damage from pests.
  • You’ll also want to inspect new plants you’re planning to introduce into your garden for signs of pests before you bring them inside your greenhouse.
  • If you notice leaves with holes in them or certain plants dying, it will be a good idea to remove them from your greenhouse as soon as possible so other plants aren’t infected.
  • Research natural ways to help get rid of any remaining pests, such as using ladybugs to help take care of pesky aphids.

But remember that even if you’re watchful, pests might still sneak onto your plants.

Check your ventilation systems

Your plants are living things, and require regular air flow to help them breathe and grow. Check consistently to make sure your greenhouse’s ventilation system is working properly. Ensure that the air vents are open at all times. This is critical to your greenhouse because the vents are what allow the hot air to move out and cooler air to move in. This exchange helps balance the climate and humidity in your greenhouse and is essential to the livelihood of your garden.

If your vents, louvres, or any other openings in your greenhouse are squeaky or sticky, use some oil to help lubricate them so that they continue to work efficiently.

Maintaining your watering and storage supplies

Greenhouse maintenance also entails making sure your tools and supplies are working properly. If you have a watering system installed, make sure it is running smoothly without any problems. If you have a hose connected to your greenhouse, make sure it does not have any holes, cracks or blockages that are preventing it from giving your plants the adequate amount of water they need.

To check for problems like these, take off any attachments you might have on your hose and assess the water flow on its highest setting. This will reveal any potential problem areas in the hose that you need to address. If you discover holes or cracks in your hose, it’s time to replace it.

Remember to always include equipment checks in your greenhouse maintenance routine!

Prune and rotate your greenhouse plants

To keep the plants in your greenhouse healthy and strong, devote some time to pruning them and rearranging them when needed. Trim off dead or dying leaves to make sure the nutrients from the soil are going to the living parts of your plants. If you notice that there are certain parts of your plants that are getting more sun than others, don’t be afraid to rotate them. Turning your plants will ensure that they receive an equal amount of light to grow evenly.

Make room for your plants to grow

Additionally, make sure there is enough space between your plants for them to grow. If they’re close and crowded together, their growth can be hindered. Use a ruler to make sure your spacing is consistent, or step back and view your pots to see if any are too close together.

Just like rotating your plants, making sure they have that extra room to grow will help ensure that all sides of your plants will be able to receive an equal amount of light.

Make greenhouse maintenance a part of your routine

Greenhouses require a lot of work to maintain, but it’s worth it for the thriving gardens they help create. Make your greenhouse maintenance a part of your routine so that your plants receive the nurturing environment they deserve.

Greenhouse management as an occupation

Greenhouse management, as an occupation, incorporates aspects of many different disciplines. Engineering, chemistry, biology and physics are all employed within the framework of a greenhouse. Graceful integration of these varying aspects is the trademark of a well-trained greenhouse manager.

A greenhouse can be built around several basic designs. Knowing what designs will enable the best use of space for growing is the key to effective greenhouse management.

The Quonset style, for instance, is a common design for a commercial greenhouse. However, the arched style of this design means that there is limited growing space along the sides.

A gable style greenhouse, on the other hand, is built more like a house, with much taller walls supporting a pointed roof. These are also much stronger designs and are, therefore, often made from glass.

Knowledge of biology and chemistry are essential parts of greenhouse management. Because of the wide variety of plants contained within the average commercial greenhouse, a competent manager must be familiar with the biological and growth requirements for each species being sold. Expertise is required for everything from the correct choice of growing medium to the appropriate fertilizer to lighting conditions and irrigation needs. Proper nutrition is vital for growing healthy plants of any variety. A greenhouse manager must be able to diagnose when there are chemical deficiencies or imbalances in plants. These deficiencies can have detrimental effects on the plants and must be adequately addressed if the greenhouse is to be successful.

Irrigation is also an essential part of greenhouse management. The irrigation system for a commercial greenhouse is the lifeblood of the operation. Designing and maintaining these systems takes a great deal of knowledge and experience. If done improperly, they can have adverse effects on the business.

Most greenhouses use watering systems that apply the water to the top of the grow medium. But many also utilize hydroponic systems that have different maintenance requirements. These systems can be further complicated by the variety of plants within the greenhouse, as different plants have different watering needs.

Effective greenhouse management must include knowledge of the chemistry of the water flowing through these irrigation systems. Elements such as Magnesium, Calcium and Sodium must be monitored at all times to ensure proper plant growth. The ability to properly balance these elements within the greenhouse water supply is often only gained through experience.

The ability to combine each of the above aspects, and use them in an effective manner, is the key to greenhouse management. When you combine these pieces with the addition of personnel and supply management, the job of greenhouse management can seem like a daunting challenge. However, as most people in these positions will attest, the rewards greatly outweigh the costs.

Are you looking to start a greenhouse or are you in need of supplies? Let us know how we can help you with your greenhouse needs today!

Conclusion

A greenhouse is a building made of plastic, glass or wood specifically designed to create an ideal environment for plants to grow in them. They work by trapping solar energy within their walls and transferring them onto the plants. Solar greenhouses, commonly used in the Northern Hemisphere, are more effective in using the existing solar radiation to increase temperatures within the greenhouse. They use different techniques to transfer heat into the soil, trap sunlight even when adequate amounts are not found in the atmosphere and retain heat by using several items like sand bags, rocks and bricks.

Greenhouse gardening for amateur gardeners can have many mental and physical benefits. Growers can cultivate plants for their own uses and also for commercial sale. They can also sell plant products.

It is essential to maintain a greenhouse well once built. The structures must be cleaned properly, especially after every season, and checked for damage and pests. Many people study greenhouses as a discipline, seeing its scope in the future. The rewards of greenhouse farming are many, not just for the grower, but the environment and ultimately, the global community as well.