They aren't really inside. It's a small deck area which is enclosed by clear plexiglass as the roof and south side. 3 of the four walls have good sized windows, with one of them being a sliding glass door. They get direct sunlight (albeit through clear, clean plexiglass) for at least 8 hours every day. I can't grow things like tomatoes, eggplant, pepper, corn outside where I live. The highs during summer are in the low 60s. In addition to the low temperatures, there is an almost-constant significant wind which is decidedly cold at all times, it blows straight off of the ocean which is 1 block away in two directions (if you walk straight west from my house for a block, you are on the beach. Same for if you walk straight south from my house, because the coastline bends). 40 mph winds are not at all uncommon here, even during a sunny clear summer day. My only way of growing these heat lovers is in a greenhouse or other good, secure sheltered situation. Which I believe that they have where they are. If not, it was a learning experience and I'll do something else next year.

if you are not looking for fruit i would grow basjoo (8 ft.) because it is cold hardy for your zone. you could even plant them in the ground right along the fence with thai-black which is a tall black stem. muesella lasiocarpa is also cold hardy dwarf, it has a huge flower, no fruit. its in the banana family. google these three names for pictures, all three can stay outside in the winter. a good dwarf for container is dwarf red, excellent fruit, siam ruby which has red foliage. these need to be winterized. you can also grow tall alocasias along with them

Banyan Sorry about the gallon thing but I did not notice that you lived in the metric world. The multiplier for gallons to liters is 3.79 X gallons = liters. The 16 gallon containers actually were heavy duty tubs purchased from Home depot. They would calculate to be 60 liters if my math is correct. I also have problems with our nursery pot sizes so I use a volume calculator to identify gallons per pot. Over the weekend I removed the three papayas from these 16 gallon/60liter containers and the roots just filled most of the container plus their roots had gone through the drain holes and into the ground. If not for this I imagine that the growth would have been less. The other in ground papayas did really well, but the cold weather arrived before most of the fruit were ready for harvest. I estimate that I harvested approximately 25% of the crop. After the freeze (26 degrees) two weeks ago the remaining fruit fell to the ground and immediately started to rot. I will try the red maradol papaya this spring , because it fruits quicker and sets fruit at 35 cm above ground. This variety is self fertile and has a gender of 66% hermaphrodite and 33% female.

There's a difference between "recommended" and "allowable" minimum window size. As stated before, local codes vary. In my neck of the woods the ALLOWABLE minimum is 8% daylight and 5% egress/ventilation. So if the room was 10' x 10' which is 100 sq. ft., one would need a minimum of 8 square feet of glass and a minimum of 5 square feet of natural ventilation when the window is open. However, in my opinion that allowable minimum is somewhat small by today's standards. That's the amount I'd typically find in a house built in the 1950s. In newer homes it's more common to see the glass area be equal to about 15% or more of the square footage of the room. Windows today are much more energy efficient than those of the 1950s, allowing larger glass areas without the adverse effects of temperature extremes. Using the previous example, that 10' x 10' room would then have a minimum 15 square feet of glass (perhaps two windows 2' x 4'). It's brighter and more cheerful. My own personal goal if I were to build or remodel would be to shoot for 15%-20%, depending on the room. I hope that helps!