Updated at: 27-04-2022 - By: Sienna Lewis

In a tiny greenhouse, there are many ways to provide ventilation, including natural ventilation and the use of fans. Putting up a greenhouse has become a popular choice for many farmers in recent years.

Using a greenhouse is a great way to keep your plants out of harm’s way. So, you can expect to acquire bigger harvests thanks to the healthy plants and flowers that have thrived.

Cold air is in short supply due to the high frequency of hot weather in many regions. Keep in mind that a plant’s ability to produce fruit and flowers over the long term is directly related to its access to cold air. As a result, farmers must master the art of ventilation and air circulation to ensure the health of their entire crop.

If you’re still unsure about how to ventilate a tiny greenhouse, continue reading this post because it seeks to answer your questions.

Types Of Ventilation For A Small Greenhouse

You’ll need to know the different forms of ventilation before anything else. Educating yourself on this topic will help you choose the best way to ventilate a small greenhouse using your available resources and taking into consideration the specifics of your growing environment.

DIY Greenhouse - A Step-By-Step Guide

Let’s take a closer look at fan and natural ventilation.

Natural ventilation

Natural ventilation is the first method of ventilation. Most of the time, it’s based on scientific theories about how air and warmth move through the atmosphere.

In the greenhouse end, this is typically accomplished using a putting-up window and movable louvers near the roof. The major goal of this sort of ventilation is to keep the warm air near the windows while the cold air is pushed out by the outside air.

Many growers, on the other hand, believe that this variety is more difficult. It’s important to keep an eye on the windows and louvers to see if they need to be opened or closed.

As a result, regular upkeep is required due to the unpredictable nature of the weather. To be sure, you should inspect the louvers after they are installed, but this takes up too much of your time and work. In fact, it’s a need.

Tips To Generate Ventilation Using Natural Ventilation

Here are a few things you can do to ensure that you have enough natural ventilation. Since it’s cost-effective, this method is popular with newbies who don’t want to break the bank just yet.

#1 Choose the right size of the vents

The roof’s area should be taken into account when accomplishing this. It should cover the same area as the sidewall vents, if not more. In addition, the size of the vents must be between 15 and 20 percent of the floor surface.

A substantial volume of heated air will be expelled while a sufficient amount of cool air is drawn in. If the vent’s size is correct, the greenhouse’s plants will benefit from the dispersal of cold air.

Because of its size, it may not be able to chill the entire area; it may be too slow and focus on a specific area, causing it to distribute cool air over and over.

#2 Choose the proper location of the vents

The vents should be installed higher than the bench, if possible. It’s a great way to get the air in your greenhouse to mix before it gets to the plants. So, even if you set your plants on the floor, you may expect healthy development and higher harvests.

It is for this reason that the greenhouse’s natural ventilation is aimed at affecting all of the plants. In the case of a gutter-connected greenhouse, we recommend attaching your vents to the roof rather than the floor.

#3 Make sure the height of your greenhouse

The temperature drops as you ascend in elevation. If you balance the air with the plants, you’ll get good results. Our advice is to not spend money, time, and effort increasing the greenhouse’s height if you are happy with it as it is.

It’s as simple as raising the height of your benches or installing new vents of the suitable size and location.

#4 Improve your greenhouse orientation

Sidewalls that follow the natural flow of air should be used. Using this method ensures that the greenhouse will receive a steady flow of cool air, and it will not miss a single plant.

In the end, you’ll be thrilled with the outcomes. Please build your greenhouse in an area where there are fewer trees and infrastructure if you haven’t already.

Airflow can be slowed or even halted entirely by obstructions in the path. On the other hand, a large number of people are praising fan ventilation. During the summer, when the air is naturally hot, it is most noticeable.

Fan Ventilation

However, you may also use the fan ventilation to supply your plants with fresh air. Cold air is produced and pushed out of the building using electric fans. It is also useful in that it can be placed anywhere you think it will be most effective.

The only requirement is that it includes movable panels and spaces to allow for the passage of cool air. A large number of people favor this type because it does not necessitate any upkeep.

You only have to set it up once, and it will automatically determine the ideal temperature for your plants to thrive. However, if you want your ventilators to work regularly, you’ll need to be financially prepared to pay a significant amount each month for your electrical supply.

Things to consider for a better ventilation

The operational considerations are extensive, therefore we’ve compiled a list of them for you.

#1 Choose a ventilator with a highly efficient motor

With this, you may run your business continuously, and your plants will be healthy as a result of the constant availability of the essential ingredient air. Additionally, it prevents overheating and conserves energy, resulting in lower monthly utility costs. Air movement is critical to the development of your plant.

#2 Locate the thermostats at the center of the greenhouse’s growth area

Doing so will give you a lot more air control. Since air flows in the middle, placing your thermometer there ensures that you’ll get accurate results.

#3 Make sure the capability of your fan

The proper volume of air at the right frequency should be delivered by your fan. In addition, the greenhouse’s air supply must be sufficient to cover the entire area. If it continues at its current pace, it won’t be able to spread outside its immediate area.

#4 Do not put your fan near an area with prevailing hot air

The greenhouse will only be able to handle the heat and expel it. If you don’t do this, you won’t get anything out of your efforts to install the electric fans.

#5 Use the needed level of ventilation

Leaving it on the highest setting could result in overcooling, which is bad for your plants. It is highly recommended that you utilize thermostats to determine the temperature that your plants require.

#6 Close the doors

Close the doors and allow the ventilators analyze and adjust the airflow, rather than having the doors open. Evaporative cooling can be improved by filling your greenhouse with plants.

The Importance of Greenhouse Ventilation

Using a greenhouse is a trial-and-error procedure. Understanding why proper ventilation is so critical to successful greenhouse gardening is an important first step in the process.

  • regulating the temperature. Inexperienced greenhouse gardeners are always surprised by how quickly the temperature rises. There must be a method for hot air to escape if you want to keep the temperature where it needs to be for your plants to thrive. A greenhouse’s added warmth is appreciated by most plants, but too much heat will kill them.
  • To photosynthesize, plants require a constant supply of fresh air. Carbon dioxide from the atmosphere is essential for plants to synthesize the sugars they need to survive, in addition to water and minerals. An open-air greenhouse provides a constant supply of fresh air for all of the plants. The plants will be unable to photosynthesise without enough ventilation.
  • Pollination success is improved. Tomatoes, eggplants, and peppers are just a few examples of plants that rely on wind to disperse pollen. Due to the blooms’ inability to be pollinated while enclosed in a greenhouse, plants are unable to bear fruit.
  • Pests and diseases can be prevented by preventing their spread. The absence of wind is conducive to the survival of insect pests such as the common house whitefly. Every horticultural pest will flock to your greenhouse if it doesn’t have proper air circulation. A warm, humid environment with minimal air movement is ideal for the growth of fungi such as powdery mildew.
  • Roots and stems are strengthened by this product. Plants that are allowed to grow in the open air have to adapt their stems and roots to withstand the wind. Plants will grow stronger stems and roots if they are subjected to the gentle force of the wind in a greenhouse environment.

Does a Small Greenhouse Need Ventilation?

It’s tempting to assume that ventilation is only important in large greenhouses, but is this actually true? Every time, yes is the answer.

It is possible for temperatures to soar even in a small greenhouse, such as one fashioned from hula hoops and a translucent plastic sheet. A good cross-breeze is essential even in the tiniest greenhouse.

Even if a tiny greenhouse just has a few vents, a fan will significantly increase air circulation.

The greater the greenhouse’s size, the more air vents it will require to move the air about. Many more air vents are required around the ceiling and the base of a medium- to large-sized greenhouse without a fan.

Manual versus Electric Ventilation

It refers to vents at the top and bottom of the greenhouse walls that must be opened and closed manually each day. Natural convection causes a cross-breeze to form around the vents.

As the sun begins to rise, the temperature inside the greenhouse climbs. The greenhouse’s warm air expands and rises to the roof, where it can be expelled through a hole in the roof. Since there is less pressure near the ground, fresh, cool air may be drawn into the greenhouse through the lower vents, supplying plants with oxygen-deficient air.

Electric ventilation is the process of removing hot air from the greenhouse and bringing in fresh air through the use of exhaust and circulation fans. It’s possible to power these using electricity from your home’s mains supply, as well as with solar power.

Electric ventilation saves time by eliminating the need to manually open and close the vents throughout the day. The exhaust fan can easily be connected to a timer to start and stop automatically at predetermined times. There is no need to hire someone to watch your greenhouse while you’re away for the weekend.

How Much Ventilation Does a Greenhouse Need - Krostrade

Types of Greenhouse Fans

It’s possible to find a fan that is both low-tech and high-tech. The most common are:

  • Fans for removing exhaust or extracting air. Similar to the ceiling fans seen in bathrooms and above the stoves, these suctions out hot and humid air from the greenhouse.
  • Fans for circulation. The purpose of this sort of fan is to circulate air within the building.
  • The use of wall-mounted fans. A better cross-breeze is made possible by using these to move the hot air trapped at the roof of the greenhouse.
  • Enthusiastic standing room only attendees. Good air circulation can be achieved with the help of fans that stand on the greenhouse’s floor.
  • Fans for temperature management. The speed of high-tech greenhouse fans can be controlled by a thermostat that monitors the greenhouse’s temperature. Despite the higher price tag, these products are well worth the money.

Ventilating a Greenhouse Without a Fan

The natural, low-tech method of ventilating your greenhouse is totally acceptable. It’s possible that you’re trying to save money on the construction of your greenhouse, or that the thought of having to pay more for electricity scares you.

In order to avoid the usage of fans to air your greenhouse, the design of the greenhouse is critical. To guarantee proper cross-ventilation, the design must have a greater number of vents.

Ideally, the top and floor of the greenhouse should have vents on opposite sides of it. This will ensure a constant flow of air through the greenhouse.

Advantages & Disadvantages of Using a Fan in the Greenhouse

Consider these benefits and drawbacks if you’re still undecided about installing a fan in your greenhouse:


  • Fans keep the greenhouse’s air moving.
  • You’ll have more flexibility because you won’t have to remember to open and close vents every day.
  • Success in pollination for plants that are self- or wind-pollinated.
  • Plants, especially seedlings, benefit from increased air pressure by developing stronger stems and roots.
  • The greenhouse is less likely to become infested with pests and diseases.


  • To purchase, install, and run, fans are an additional cost.
  • Especially if they are solar-powered, they add another level of upkeep to the greenhouse.
  • When constructing a greenhouse, it is necessary to locate it close to a mains power source.

Reasons Why Greenhouse Ventilation is Important

For more than just the obvious reasons I discussed at the beginning of this post, greenhouse ventilation is essential. All the methods that ventilation helps to keep your plants healthy are listed below.

  • the temperature of a room
  • Humidity is controlled
  • Carbon Dioxide is a byproduct.
  • Inhibits the Growth of Pests
  • Pollination is facilitated

A greenhouse’s temperature can be influenced by a variety of factors, not the least of which is the amount of sunlight it receives.

Even in the cooler months, this is a possibility. Plants may droop or even die if heat is retained in the greenhouse, which is detrimental to their growth. Your plants will flourish if you install a ventilation system to remove any excess heat from the room.

Humidity can also build up in your greenhouse, so you’ll want to keep an eye on that. If you don’t remove the water from the plants, it will accumulate in your greenhouse, raising the humidity level.

Despite the fact that some plants thrive in high humidity, most are susceptible to all the nastiness that comes with it, such as the growth of mold, fungus, and mildew. Ventilation helps control humidity by removing the damp greenhouse air and bringing in fresher, drier air from outside the building.

Your greenhouse humidity can be reduced by removing weeds from the ground, as they contain a lot of water.

It may be a good idea to invest in a humidity sensor. On Amazon, I discovered a thermometer that not only monitors temperature, but also humidity.

As a general rule, it’s crucial to keep an eye on both temperature and humidity because they are closely linked.

Based on the temperature, the following chart shows what percentage humidity you should maintain in your greenhouse.

Ventilation in your greenhouse is necessary if you aren’t giving your plants with carbon dioxide from the air. This is done using a ventilation system.

In order to perform photosynthesis, plants require carbon dioxide. It’s the mechanism through which they convert carbon dioxide, water, and sunshine into glucose, which they need to live.

Photosynthesis slows down and your plants don’t develop as effectively as they should if carbon dioxide levels drop.

The usage of a ventilation system can also assist keep your plants safe from typical greenhouse pests. Pests thrive in warm, moist environments, which is why having an effective ventilation system in place is essential.

It’s a good idea to become familiar with the main greenhouse pests so you can keep an eye out for them. Here are a few of the most frequent pests that might infiltrate your greenhouse.

  • Aphids
  • Gnats
  • The flies of the shore
  • Bloodworms
  • Thrips
  • Whiteflies
  • Leafminers
  • Mealybugs
  • Spider mites with two spots
  • There are mites on cyclamen plants.
  • Dirty little critters.

A wind blows or a humming bee hops from blossom to flower doing its task to pollinate outside of a greenhouse, which helps with pollination. There is no wind in a greenhouse, on the other hand.

It is important to have a strong ventilation system with good fans in order to encourage pollination of the plants. If you discover that your greenhouse plants aren’t bearing fruit, you may have a problem with pollination.

A robust ventilation system is essential for controlling all of the previously mentioned environmental conditions, so that you can grow the healthiest, most productive plants possible.

Types of Ventilation Systems for Greenhouses

A greenhouse ventilation system is necessary, so now you must decide on the best method of ventilation for your greenhouse. Natural and mechanical ventilation systems are the two most common forms of ventilation systems.

An introduction to the fundamentals of each system is provided here.

Natural Ventilation

In the table above, you can clearly see how natural ventilation works in a greenhouse. Wind and thermal buoyancy are used to move the air instead of fans. The concept of thermal buoyancy is based on the notion that warmer air naturally rises to a higher elevation.

Vents on the greenhouse’s sides and on the roof are common among those who use natural buoyancy. Heat rises and escapes from the roof vents as the temperature in the greenhouse rises.

Vaccuum formed by evaporation of the hot air from the roof vents causes the side vents to draw in cooler air. If you have a windy day, you can use the side vents of your greenhouse to draw in cooler air.

It’s a good idea to acquire and install a solar powered vent opener if you choose for natural ventilation. Temperature increases cause the paraffin wax in the mechanism to expand, causing the vent to open.

Because they are driven entirely by the sun and do not require any energy or batteries, solar-powered vent openers are more convenient. On Amazon, I came upon a solar-powered vent opener.

Mechanical Ventilation

Your greenhouse can be ventilated mechanically using fans or other devices.

Controlling the flow of air in your greenhouse is a lot easier with mechanical ventilation. You have complete control over when and how much power the system uses. Your plants are protected from pests since the greenhouse is completely enclosed with a mechanical ventilation system.

Pros and Cons

There are a number of factors to consider when deciding which sort of ventilation system is appropriate for your greenhouse.

The only cost associated with a natural ventilation system is the time and effort required to construct the vents. While mechanical ventilation systems cost you money every time you use them, natural ventilation is free.

If you rely on natural ventilation, you’re at the whims of the elements. There is less ventilation when there is less wind. You can control the timing of a mechanical system.

Choosing the Right Spot and Size for Your Ventilation System

Choosing between a mechanical or natural ventilation system will have an impact on the size and location of your ventilation system.

For natural ventilation, you can roll up a part of the wall if your greenhouse is built of a more flexible material. Having said that, if it’s made of more hard materials, it will require more effort on your part to guarantee adequate airflow.

For a natural ventilation system to work well, it must have ridge and sidewall vents. Each sidewall vent should have a length of at least as much as the length of the roof vents. Around 20% of the total floor space should be allocated to each region. You can see several instances in the following table.

If you’re using natural ventilation in your greenhouse, it’s a good idea to have a fan to circulate the air around your plants. Fans like this one I got on Amazon should be fine.

Before deciding on the size of your greenhouse’s mechanical ventilation fan, you must choose whether you want to utilize it year-round or only seasonally. If you plan to use the fan year-round, choose a fan size based on the hottest months of the year.

It’s best if the equipment is controlled by a thermostat or has more than one fan speed option if you decide to go this route, During the cooler months, you’ll be able to reduce the intensity of the ventilation.

Cubic feet per minute (CFM) is how air volume is measured for ventilation fans. A fan with a 1-air-change-per-minute rating is ideal for your greenhouse ventilation system. The size of your greenhouse will help you determine which fan to purchase.

It’s time to put on your thinking cap and do a little mental gymnastics. The volume of your greenhouse is calculated by multiplying its length by its breadth by its height. Check out this table for a few instances.

The volume of your greenhouse can be used as a guide when selecting a fan. Choose a fan with a rating of 3,000 cubic feet per minute or above if your greenhouse has a volume of 3,050 cu ft.

Amazon’s exhaust fan has a rating of 3,000 CFM, which stands for cubic feet per minute, on the product page.

Exhaust fans should be placed near the top of the greenhouse, as heat rises. Placement of a circulating fan on the ground across the greenhouse helps circulate air in and out, even with the manual ventilation system.

A Beginner's Guide to Using a Hobby Greenhouse ~ Homestead and Chill

Using Your Ventilation System During Other Seasons

If you plan to utilize your greenhouse year-round, you’ll need to make adjustments to your ventilation system.

Your greenhouse may even require an external heat source in the cold. Because of the temperature differential between the outside and interior of your greenhouse, humidity becomes an issue.

Humidity rises as a result of the temperature differential. To avoid lowering the temperature too much, three air changes per hour rather than one per minute is a decent rule of thumb to follow.

This involves multiplying the greenhouse’s volume by.05. With three air changes each hour, we’ve recalculated the values in our previous table.

Either buy a smaller fan or pull down the dial on your current fan if it has numerous settings to get these speeds.

Fall and spring are ideal times to use ventilation to achieve a balance between removing excess heat and reducing indoor humidity levels. In this case, the thermometer that monitors both temperature and humidity is essential.

Heating Options

I mentioned earlier that heating your greenhouse in the winter might be necessary to keep your plants healthy.

At 77 degrees Fahrenheit, photosynthesis can occur, however many plants thrive at temperatures between 70 and 80 degrees Fahrenheit throughout the day.

What plants you have in your greenhouse will influence the ideal evening temperature. Look at the following plants and their ideal overnight temps.

Here are a few options for heating your greenhouse that you may want to consider.

  • Heaters that utilize traditional fuel sources
  • Electric heaters for the home
  • Portable heaters for the home
  • Radiant heaters filled with oil.
  • Ceramic heaters for the home
  • Infrared heaters for the home

Kerosene, natural gas, or wood may be used to power a typical fuel-based heater. Because they produce more carbon dioxide, these are better suited to larger greenhouses. In addition, be certain that you have adequate ventilation.

Safe and simple to operate, an electric space heater is a great option for winter heating. To heat a large greenhouse, you’d definitely need more than one of these heaters.

Because of their small size and portability, portable space heaters are a great option when you’re on the go.

It is possible to reduce your monthly electric bill by using an oil-filled radiant heater instead of a traditional one. They’re also frequently on wheels, making them easier to transport.

Heat is produced in a small box using a ceramic space heater. In terms of price and energy efficiency, these heaters are excellent. In addition, the device does not become very warm to the touch. They are best suited for compact greenhouses.

You can immediately heat up your plants with an infrared heater in a room with an infrared heater. The heated plants then cause the air in the greenhouse to warm up.

You should take into account the size and cost of your room before deciding on a heat source, after looking at all of the options.

Cooling Options to Help With Temperature Control

The installation of a ventilation system and other cooling methods helps keep your greenhouse at a comfortable temperature throughout the hottest months.

Here are a few ways to keep your greenhouse from getting too hot.

  • A Misting Equipment
  • Fogger
  • Evaporative Air Conditioning
  • Shade Clothes.

Simply put, misting systems perform exactly what they claim to do As it evaporates, it creates a fine mist that helps to cool the greenhouse.

A drawback of this design is that the misted water may not always evaporate completely, leading to increased humidity. Such a misting system from Amazon would work well for the purpose.

A fogger, like a misting device, works in the same way. Fog particles are dispersed into the atmosphere and remain there until they are dissolved. In most cases, the particles it emits are just slightly larger than those produced by a misting system. Amazon has one like this.

In an evaporative cooling system, water is stored in a cooler and then emitted into the greenhouse via an exhaust system, which cools the surrounding air. Amazon has an evaporative cooler on sale.

Using shade covers to keep greenhouses cooler is a common practice. The greenhouse is protected from some of the sun’s rays by a shade cover. There is a 20% reduction in temperature. As you can see from these Amazon shade covers, this is a reasonably priced choice.


As a general rule, ventilation is a good thing to have in your greenhouse. Of course, depending on the size and location of your greenhouse, you’ll want to figure out the best method of ventilation.

Do you know how to make a small greenhouse more airtight? This post hopes to help you ensure the health of your plants, so make sure to follow the correct procedure.