posted 11 years ago
Xisca, more often than not I am using greenhouse plastics rather than glass. In our climate with the big mountains severe hail is a frequent occurrence. Because of government funded programs in the 70's and 80's in many places in the US you can find old glasshouses that are no longer used and have them for free if you take them down. In my area this is not an option because all of the glasshouses have already been destroyed by the regular severe hail storms. The plastic that I use (called Solexx) holds up better to the hail and is a fraction the price of glass. We often use glass as accents and for aesthetic reasons, but we are always sure to protect it under an overhang because of the hail.
In climates where hail is not a problem glasshouses are great because of how long they last. They cost a lot more, but last for a very long time when maintained, and are more aesthetically pleasing. The earth temperature is roughly the mean annual temperature for a climate. If you figure out the mean annual temperature for your climate this will answer your question as to if the ground temperature will be able to provide what you are looking for. In warmer climates the earth temperature often provides a bigger advantage for keeping the greenhouse cool in the summer (as this is a bigger challenge), as opposed to warm in the winter.
