Yes, I understand that. I had two plants in pots and was moving them inside for winters. But plants are getting bigger, so I decided to experiment: bought a light (and it turned out - low quality) greenhouse, moved feijoa plants into an open ground and put greenhouse on them. My plan is to use greenhouse for winter only, disassembling it at spring. I'm now considering ways of better insulation of greenhouse. Will put some leaves and manure around it, maybe cover greenhouse with bubble wrap.

Any high quality bark-based potting soil. Not garden soil or topsoil but a constructed mix formulated specifically for container usage. But these types of soils are seldom available from bulk soil providers........you may need to mix your own. I'd suggest you visit the Container Gardening forum for details on soil mixes but I'd lean heavily to the 5-1-1 mix.

In Central Florida near the East Coast we have a big problem with fruit flies both the Caribbean variety and the standard fruit fly. I have a home orchard with two guava trees. One is a Ruby Supreme guava and the other a Barbie Pink guava. The Ruby Supreme was under incessant attack by the fruit flies. Nothing I tried including spraying or using traps with apple cider vinegar and dish soap could eradicate them. Actually, the latter seemed to be effective against the Caribbean fruit fly but not against the standard fruit fly. To make a long story short I uprooted and destroyed the Ruby Supreme guava tree. It was painful because I love guavas but it's just too much trouble dealing with those pesky critters. The Barbie Pink guava is still in my orchard but I have noticed the fruit flies attacking it. So I removed all the fruit and threw them away. I will most likely destroy that tree also later this winter or maybe repot it into a half whiskey barrel planter. It might make a good gift for my sister if/when she buys her own home. Or if I could get a greenhouse installed in my yard then I could isolate the tree from the flies. I also have the feijoa selliowana (aka the pineapple guava) tree in my garden. The 5 of them are in pots and I had thought about making a hedge out of them. They don't seem to tolerate the blistering summer heat of Florida so they need to be in shady spot during the late afternoon hours. I am not sure if the fruit fly can attack the pineapple guava because it seems they have a much thicker peel than the ordinary guavas. A thick peel is the best line of defense against fruit flies I hear. I was hoping someone on this forum could confirm if they are resistant to fruit flies or not. But it has to be a report from someone who lives in an area that is prone to that sort of infestation.

Luckily this tree doesn't need much from us. Some landscapers did give it an ugly pruning though... I never thought of this as being hedging material but now I am. My only experience is with this tree which is decidedly a tree. It came with the house and I wouldn't be surprised if it's 40+ years old. I'm currently redoing much of my front yard and could use a nice shrub or two. The feijoa is kind of pretty and popular with the wildlife.