Now this is just a brainstorm because I am very unlikely to ever be able to get enough material to create this idea. (Unless I raid a recycling facility several times!)

I just saw a kid craft for making an igloo out of milk jugs and my mind took a sideways jump. What about making an igloo greenhouse out of 2 liter jugs? Fill the jugs up to a certain level with dirt, and then above that with water. The natural gaps between bottles would provide ventilation during the warms seasons and during cold seasons a layer of clear plastic would provide a frost/freeze barrier. Maybe two layers, one outside and one inside. The filled bottles would provide thermal mass to remain warm and keep the greenhouse warm.

I already use 5 gallon oil jugs filled with water as thermal mass in my small greenhouse. I end up with a total of 100 gallons. Painting black helps them gain more heat. But painting wouldn't work for this idea, unless you paint the ones that you fill with soil.

Anyways, any thoughts? modifications? Glue ideas that are not hot glue?