I wrote a new article for my website Blog and Forum and thought I would share it here. I thought these might qualify for the 5 most common mistakes new hobby greenhouse owners make. What do you think?
Five Common Mistakes Made by New Hobby Greenhouse Owners
Many new hobby greenhouse owners mistakenly think that now that they have a greenhouse, they will have great plants, but that couldn't be further from the truth. These greenhouse owners are prone to making mistakes that work against their goal of a greenhouse full of healthy, thriving plants. A greenhouse is much more than having a bright and warm outside room in which to raise plants; it is a balance of many factors, an art and a science fraught with pitfalls for the new, unsuspecting greenhouse owner. Here are the five most common mistakes made by new hobby greenhouse owners.
Probably the number one mistake made by new owners happens before they ever have their greenhouse up and running. They choose the wrong location to place their new greenhouse. Location is the basis from which all else is built and placing a greenhouse in the wrong location can spell failure from the onset. Obstructions like other buildings and trees are often overlooked. A greenhouse should be placed with its longer side running east to west to take full advantage of the sun and there should be no buildings or trees that block the sunshine other than maybe early in the morning or late in the afternoon.
Ironically, the second most common mistake is just the opposite. Failure to provide adequate shade for plants under intense sun and high greenhouse temperatures puts undo stress on them and can cause heat damage which can kill or weaken the plants enough to open the door to disease and increased vulnerability to pests. Every greenhouse owner should have shade cloth and an easy way to deploy and retract it as needed depending on the sun's intensity and temperature in the greenhouse.
Temperatures must be constantly monitored. Large temperature swings are detrimental. For most common seasonal greenhouse plants this means average summer daytime ranges of between 75-85 degrees and nighttime temperatures between 65-75. In the winter this can be adjusted to 65-70 during the day and 40-50 during the night. Of course, many plants can tolerate, and some may even need, slightly different averages; these can be easily researched, and adjustments can be made, but keeping greenhouse temperatures within moderate ranges, avoiding extremes, only benefits your efforts. In addition to shade cloth already mentioned, properly sized equipment designed for greenhouse heating and ventilation with automatic controls should be a part of every hobby greenhouse.
Humidity control goes hand in hand with temperature control. Relative humidity in a greenhouse affects plant transpiration, the flow of water through a plant; however, because the capability of tracking and modifying the relative humidity is complex and involves expensive equipment, let's keep it simple here. Generally, prevent situations that can cause rapid changes in temperature like letting too much heat build up or allowing your greenhouse to get too cold. Know the average temperature ranges for your plants throughout the seasons and work to keep your greenhouse within these average temperatures. This alone will go a long way to preventing problems that can arise from extreme relative humidity levels.
Circulation of the air in the greenhouse will also aid in keeping temperature and humidity levels constant and avoid such problems as excessive surface soil and leaf moisture which can lead to mold, mildew and harmful fungi. Properly placed fans will equalize the temperature and carbon dioxide throughout the greenhouse and help keep humidity from forming condensate on plants, soil and other greenhouse surfaces. Circulation coupled with a proper watering regimen based on your plants needs in their greenhouse environment is another key to a healthy greenhouse.
If you make it your priority to stay aware of the environmental changes in your greenhouse, you will be on your way to success. It takes work and knowledge, but remember you reap what you sow. The more closely attuned you are to location, light, temperature, humidity and air circulation, the better able you will be to make the needed adjustments, minimizing damage and giving you a greenhouse full of healthy plants.
©Jim Guinn
HobbyGreenhouseGrowers.org and .com
to NGA and 
I don't know if it will happen, but I hope so!
