A Greenhouse for the Garden

by blackspanielgallery

Greenhouses have a multitude of functions, and come in a variety of types. A greenhouse can enhance a garden, but must be matched to the needs of the gardener.

A greenhouse is used to raise the temperature in a controlled environment during the day, and maintain a relatively warmth during the night. It can be important in keeping the temperature high over cold nights preventing plants from being damaged by getting too cold.

The method by which a greenhouse works is simple and easily understood. The construction requires transparent windows. Light freely enters and strikes surfaces, including plants, tables, and the ground. Solid objects absorb some light, and reflect the rest. The absorbed light is shared by the molecules of the solid, including some below the surface. When a solid reemits its energy there is less per molecule to emit, so it emits lower energy infrared frequencies over a longer period of time.

To understand better how a greenhouse works look at a window, then look at a mirror. Notice that one passes light, and the other reflects light. Well, windows act as mirrors for infrared frequencies, so the waves of infrared coming from within the greenhouse get reflected back. The energy does not efficiently escape. Light entering, then being emitted back after the energy is in the infrared part of the spectrum allows energy to build in the day, then have a slow release, even at night.

Trapped energy causes a temperature rise. It is reabsorbed by the solids, raising the temperature, then through contact heats the air. And some is also absorbed directly by the air.

Use Greenhouse Kits

Greenhouse Kits Use the right Materials

The idea of having light enter, and reflect infrared rays back requires careful choosing of the construction material.  Use a kit and feel your greenhouse will be efficient.


Of course you must choose your kind of greenhouse.  One size does not fit all.  Some are portable.  Some are small with several transparent shelves so light can fall on plants below the top shelf.  Others are large enough to walk through.

Why Use a Greenhouse?

What Are the Purposes of a Greenhouse?

There are many purposes for a greenhouse.  In addition to controlling temperature, water is controlled. 


Rehabilitating plants in distress is one use of a greenhouse.  This might not be enough of a need to justify the expense of buying a greenhouse, but is a plus if you already have one for other purposes.


Having a start on the growing season by planting seeds before the outside temperature is warm enough to permit direct planting into the ground is a real advantage for those who have a greenhouse.  Most seedlings are very susceptible to frost damage.  And, having mature plants earlier can bring your harvest sooner, and even extend the season by allowing you to stagger planting over several weeks.  Starting seedlings indoors might allow too little sunlight to establish the young plants.  But a greenhouse permits light to reach them in abundance.


Another reason for a greenhouse is to grow plants that normally grow in a different climate.  Tropical plants can often be grown in a greenhouse.  If you experience short days there might be a need for artificial light, but you can enjoy such beauties as orchard simply by walking into your greenhouse.


A greenhouse can be a dry place for storing garden tools and bags of fertilizer that must be kept dry.  A little space in a corner of a greenhouse can eliminate the need for a tool shed.  In fact, under a table might work well for storing such items.


A greenhouse allows your plants to be placed on tables, making bending over to tend them unnecessary.


One real advantage is weed seeds and air borne diseases are less likely to invade your garden.

Garden Club Mug


Greenhouse Companions

Other Items You Might Want

Small greenhouses need gentle watering, so a watering can might be a wise addition.  And hand tools work well with small plants, especially potted plants.


Seedlings need to be started in something.  There are special, compartmentalized planting units for starting seedlings.  They cannot just be grown in one flat container because the roots will tangle, and damage in transplanting will occur.

Problems with Greenhouses

All Is Not Great

The first obvious challenge you will have is the need to water your plants.  You can have an irrigation system if the greenhouse is large enough.  Or, you can water by hand, especially if you have a small greenhouse.  Allowing nature to provide direct water by rain is not always possible.  Most greenhouses have no access for rain.


Heat buildup can become excessive.  Some greenhouses have windows that open, and opening the right number of windows is important.  You might use an automatic system that closes windows at night.  In some climates this might not be a consideration, but in warmer climates there is a real problem with too much heat.  Some larger greenhouses have ventilation systems, and regulate the temperature more precisely.  That is a feature home greenhouses may not need unless you are growing prize winning plants, or are a real serious gardener.  More complex additions to your greenhouse add expense.


Pollination is another issue.  Growing tropical plants, or starting seedlings, does not require pollination, but growing plants for a food source may.  A greenhouse with windows that open will allow bees access to your plants.


Animal control is another problem.  Animals borough under things, so it may be necessary to build on a slab of concrete.  Yes, it is cheaper to place your greenhouse on the ground, but animal control is also important.  And, in the section below on anchoring you will see another reason for a slab floor.


Glass is susceptible to hail damage if the hailstones are large enough, especially in the roof area.  Choose a material that does not break so easily, but works like glass in admitting light and preventing loss of infrared rays. 


Anchor Your Greenhouse

Stabilize It

Winds, especially high winds, can topple and even transport small buildings.  You need to provide an adequate anchoring system to hold your greenhouse upright, and in place.  A flying greenhouse not only will be damaged, but is dangerous. 


Anchoring is easier if you actually pour a slab upon which you erect your greenhouse.  Anchors can be inserted into the wet concrete, and thus become firmly part of the foundation once the concrete cures.  Just make certain you use strong enough material, and enough anchors, to keep the greenhouse from breaking away. 


Choose the right greenhouse for your needs.  If it is only to grow a few seedlings you can use a small shelved unit that you simply open a door and reach into.  If it is for a large tropical garden you will need a larger unit that you can walk through to enjoy the plants.  And, if you use it seasonably you can select a portable greenhouse.

This article contains links to affiliate programs and Adsense advertising.  These must use cookies to allow for proper crediting. As an Amazon Associate I earn from qualifying purchases.


The introduction uses one of our own images, and is our Zazzle product.

Updated: 01/02/2020, blackspanielgallery
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frankbeswick on 07/14/2017

Thanks. Horticultural scientists know that hard barriers deflect air, but can cause turbulence, which is known to do damage to some gardens after the protective effect of the barrier has been lost.

I suffered a bit of this a year or so ago, when there was damage to greenhouses on plots 5-9 [I am on plot seven] Localized turbulence seems to have been the problem, but it has not been repeated.

blackspanielgallery on 07/14/2017

Frank, in order to set up rotating air something must cause it. A partial vacuum as air above reduced pressure either on the sides of the houses or in front of them could very well be the problem. As per einstein, it is insanity to perform the same experiment and expect different results. Once could be a fluke, repeated similar problems indicates something is causing the problem.

blackspanielgallery on 07/14/2017

DerdeiuMarriner Different parts of the country often use different words. with television it is getting more standard, but has a long way to go.

DerdriuMarriner on 07/14/2017

blackspanielgallery, People, such as I originally, from the extremer parts of the Northern States favor glasshouse, over greenhouse, as a statement of preference for building materials and as a synonym for hothouse in a home conservatory. My tendency still is toward glass over plastic.

frankbeswick on 07/14/2017

There are rules set by the council to ensure that greenhouses on allotments are well secured. The council insists that they must meet certain criteria, and that they must not be built from scrap, so as to ensure that they are firm.

By the way, I have stepped down as chair of the gardening society, as I needed a rest. But yes,greenhouse stability does come up.

Now here is something for a physicist. One plot holder on our allotment has on two or three occasions been victim to a vortex which has destroyed her greenhouse. It is known that physical barriers protect against wind for ten times their height. A line of houses,probably about forty feet high, stands across the path of the wind, and her greenhouse is about 450 or so feet from them, just enough for wind deflected upwards by the houses to come down as turbulence. On Karen's greenhouse! I think that she is unfortunately sited. What is your physicist's opinion of my explanation?

blackspanielgallery on 07/14/2017

Too many people assemble things such as small buildings without giving anchors a thought, and do not read the entire set of instructions. I had no doubt your greenhouses would be well anchored, but I felt others needed the warning. I would think it could even be a topic at your garden club from time to time. It is so critical to being responsible.

frankbeswick on 07/14/2017

My greenhouses are pegged down differently. Number one is bolted to a concrete base and also cemented in with Pink Grip. My "new" [second hand] greenhouse is weighted down by paving stones. The bars that lie on the ground are L-shaped in cross section, so the paving slabs rest on the flat bit of the L. The arrangement has worked very well and has withstood strong winds.

blackspanielgallery on 07/14/2017

Glad you liked it.

Veronica on 07/14/2017

Thanks for another science article. As a non scientist I love learning about science in your clear style. I think you must be a wonderful teacher.

Yes I thought that Americans say glass house. I don't know where we get that idea from.

blackspanielgallery on 07/13/2017

This area uses its own words, but here there are two options: greenhouse and hot house. I have never heard glass house used. In fact, the greenhouse effect is named for greenhouses, although the mechanism is quite different. There is no reflection in the greenhouse effect, rather an absorption. Since greenhouse effect is as well used as global warming I suspect it is the most common term. But, here we say things unique to the area, so I am not certain. The only time I heard glasshouse was associated with a glass roof cover restaurant, but that is a different thing.

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