Unless you are planning to work with a high tech greenhouse with all types of specialized equipment and systems, a greenhouse is a relatively easy tool to master. A greenhouse uses passive solar energy to provide a warm moist place for plants to grow and thrive.
The sunlight passes through the glass or plastic exterior of the greenhouse. The long warming rays of the sun are trapped inside to increase the interior temperature. The sealed exterior of the greenhouse provides a barrier for moisture to escape. In the warm conditions of the interior, the humidity rises and plants enjoy a near perfect growing environment.
Keep the greenhouse shut when the exterior temperatures are cool.
Since a greenhouse works by trapping heat and moisture, it needs to be kept shut when those conditions are lacking outside. Even a cheap greenhouse will raise the temperature inside on a sunny day by tens of degrees. It can be freezing on the outside, but still be warm and cozy for the plants inside the greenhouse. It is important that the greenhouse not be opened an excessive amount during these times, or the internal heat will be lost. Keeping it shut at night is important, too.
Use shelves to increase the amount of usable space in a greenhouse.
Because the greenhouse will heat its entire interior, using shelving to give more flat surfaces to put plants on will increase its productiveness. Once the greenhouse has started to generate heat, it will have no problem providing warmth for many plants and their pots. You will be able to grow many times as many seedlings by using shelves as you could otherwise grow.
Do not over water plants in the greenhouse.
When the greenhouse is shut, it will trap moisture and evaporation happens very slowly. Because of this, you do not want to pour on too much water for plants inside the unit. If you have one, using a moisture gauge is a good idea. If not, feel the soil and see if it needs to be watered. With good sunlight, greenhouses can almost produce their own rain. So, be very careful about how much water that you use on plants in the greenhouse.
Keep a thermometer in the greenhouse.
If the temperature starts to really jump up on a warm sunny day, you will need to vent the greenhouse. You can leave the door open a little. Most greenhouses have some type of vent in or near the roof. Opening this vent will let the hottest air out.
You do not want to get too carried away with this and cause the greenhouse to loose all of its heat and moisture late in the day. If the forecast is for a cold night, this can let the night temperature drop too much and harm the plants. It is a good idea to always shut the greenhouse about an hour or two before sunset in spring or fall. In the middle of summer, you should not have to worry about night time temperatures.
Leave the door open for several hours per day if you intend to produce fruit in the greenhouse.
You need bees and bugs to carry out pollination unless you intend to cross pollinate by hand. By leaving the door open, insects can get inside and do their thing with the flowers. This is the easiest way to make sure that your plants are pollinated. The other option is to set the plants outside for a few hours per day if weather permits.
