Best Green Houses

Derived From Its Operations

When you understand how your greenhouse works you will find that you can get the most out of

it. You will feel confident to experiment and try new things. Your results will be better and you

will become the envy of your friends.

Whether you want to grow ornamental subject or fruit and vegetables it pays to familiarize

yourself with the way a greenhouse works. Spending a little time on basic principles will pay off

in the end.

A greenhouse is the first, simplest and probably still the greatest solar device known to

humankind. We hear so much about solar panels and other high tech gadgets, you may even

have one of those handy solar powered devices to charge batteries, but the greenhouse is in

many ways a solar powered device too.

The greenhouse differs from other more recent solar powered devices in that it has been around

for so long it has been refined to the point that it works really well. It does its job perfectly.

That job is heating. A greenhouse uses the sun's rays to heat up the growing medium and air in

an enclosed space. It will do that without any help from us or any added extras.

In theory it would be possible to create a greenhouse that was entirely self-sufficient that could

exist without any human intervention once the system was running. The plants inside it would

create their own atmosphere by giving out oxygen and taking in carbon dioxide. Such a

greenhouse would be a model of the entire planet.

It would have to be a very big greenhouse, certainly bigger than you would want in your

backyard, and remains the stuff of science fiction at the moment. We have not quite achieved

"silent running" yet. But thinking of a greenhouse in this way helps you to understand that you

are dealing with a living system.

You have to play an active role to keep the living system in your greenhouse in balance. You

are the control system of the greenhouse.

The greenhouse will do its job of heating as long the sun shines without any help from you. But

once you put plants in there then the problems begin. The plants will not just look after

themselves.

A greenhouse is too small and the plants are typically too dense for them to be self-sufficient.

You will need to provide them with water and you will need to regulate the atmosphere.

When I say regulate the atmosphere what I am talking about is humidity. Humidity is the amount

of water held in the air. The amount of water that air will hold depends on the temperature of the

air. Air at 70 degrees will hold twice as much water as air at 55 degrees.

When the temperature of the greenhouse begins to fall the water drops out of the air. This is

known as the dew point. If plants are subjected to this for a long period they are liable to suffer

from various forms of rot, mold, fungus and mildew.

This is a natural part of the plant's lifecycle but not good for us if we want good quality crops

from our greenhouse. You can treat the plants with chemicals. There are plenty of fungicides

available on the market. But it is better to avoid the problem as far as possible by ventilating the

greenhouse.

The amount of ventilation will depend on the temperature. You need more ventilation at lower

temperatures. Open the door and a window, or use an extractor fan. However you do it get that

air moving.

Humidity is related to watering. If you apply too much water to the growing medium or water

gathers on paths and staging in the greenhouse you will have problems with humidity. Aim to

have well draining paths and surfaces in your greenhouse.

It is possible to measure the humidity of your greenhouse with a sling psychrometer. This is a

device consisting of two thermometers. One thermometer has a wick that can be wet. You

rotate the whole device for a few minutes then take a reading from each thermometer. Subtract

the reading of the wet one from the dry one and compare the reading to the chart provided. That

will give you the relative humidity.

This simple device will enable you to regulate your watering and ventilation regime in the

greenhouse. Once you get those right you will eliminate a lot of the problems common to

greenhouses. Your greenhouse system will be working well.