How Does a Greenhouse Work? A 5-Step Guide

More and more Americans are keen on leading a healthy lifestyle. It’s no surprise that backyard greenhouses have become a norm.

But how does a greenhouse work?

I’ve heard passionate greenhouse supporters claim that gardening without a greenhouse is more like cooking without a stove. Could they be right?

Affiliate Disclosure

Some of the links below are affiliate links. This means that, at zero cost to you, we earn an affiliate commission if you click through the link and finalize a purchase.

Step 1: It All Starts With The Sun

The most basic concept of a greenhouse is that all surfaces are made from translucent material.

Now, what’s a translucent material? (Let’s make our science teachers proud, come on)

My teacher taught me translucent materials are those materials that allow light to pass through them, but the objects on the other side cannot be seen with clarity.

So, greenhouses allow light from the sun to pass through the glass walls and roof.

Step 2: Light is Converted Into Heat Energy

All the stuff inside the greenhouse – be it the floor, the soil, plants, etc. – absorb the light coming in from the translucent roof and walls.

They convert this light into heat energy.

How Much Heat Energy?

Well, the amount of heat in a greenhouse depends on:

Exposure to the Sun

Greenhouses that are more exposed to the sun have more heat than others.

The same way greenhouses in sunny regions have more heat than those in regions that rarely get sunny.

The Size of the Greenhouse

Larger greenhouses generally have more heat energy than smaller ones.

The Contents of the Greenhouse

There are objects that absorb more heat than others. For instance, flooring materials like brick.

The darker colored objects will definitely absorb more light and therefore produce more heat energy.

Also, water absorbs a lot of heat, so it’s not strange to find fish tanks inside greenhouses!

Step 3: Heat Energy is Released Inside the Greenhouse

Once the objects convert the light to heat, they release the heat into the air.

They’ll certainly not release the heat in a minute; they do it gradually.

So, the air inside the greenhouse gets warm gradually, over a couple of hours.

What happens to warm air when there’s cold air?

Warm air is lighter than cool air.

So, it will rise up to occupy the top sections, leaving the colder air on the lower sections of the greenhouse.

Step 4: Heat Gets Trapped Inside the Greenhouse

Before we delve further, remember that light has already been converted to heat energy.

The trick here is that heat does not pass through plastic and glass sheets as easily as light does.

According to the Science Education Resource Center at Carleton College, heat energy has a differently shaped wavelength than light energy.

The wavelength for heat energy is longer than that of light energy.

So, while light energy can come into the greenhouse, heat energy cannot leave.

It gets trapped inside!

Step 5: The Air Inside Warms Up

With warm air trapped, it’s got to get warm inside the greenhouse.

Hurray! That’s the whole idea of a greenhouse!

The warmth inside makes growing plants easier!

Jean Vernon, an award-winning gardener with vast experience in greenhouses, mentions that the warmth inside protects plants from extreme cold.

Especially during the winter.

It’s the perfect environment for nurturing plants and maximizing their growth.

But, all this depends on a gardener’s ability to regulate temperatures inside the greenhouse.

Here’s how!

How To Regulate Temperatures Inside The Greenhouse?

It’s not too complex. Here are 6 ways to do it.

Hygrometer + Thermometer

They’ll allow you to monitor humidity and temperature inside the greenhouse.

The digital ones come as 2-in-1 and they’re more accurate.

What’s more, with a smart model, you can easily track statistics on your smartphone!

Temperature Alarm

Install a greenhouse temperature alarm to alert you of any significant temperature changes.

Heaters for The Winter

No rocket science here!

During those long winter months, get a greenhouse heater preferably with a fan to supply hot air inside the greenhouse!

By the way, they don’t have to use electricity.

Even solar heaters work!


When it gets too hot, especially during the summer, set up ventilators to shed off excess heat!

Proper ventilation is mandatory if you’re going to be a successful greenhouse gardener.

Think about opening (more) doors, windows, installing more fans, etc.

Automatic Vent Opener

How about connecting the alarm and the digital thermometer to an automatic ventilation opener?

When the thermometer detects excessively high temperature, the alarm rings, and the automatic vent opener opens up.

When the heat reduces, the vent opener closes down.

A Bubble Wrap for the Winter

To prevent loss of heat during the winter season, a bubble wrap is a very good option.

The wrap allows light to enter inside, while still providing an extra buffer against heat escape.

So, light will come in, but heat will be retained longer.