I just bought a meyer lemon tree and I wanted to get your opinion on whether I should grow it in a container or outside. I looked at the USDA Hartiness map and typed in my zip code they said I was in zone 7 (but I think I live pretty close to zone 8). On the legend it said the freeze range was 0 to 10 degrees, but It never gets that low where I live. In winter the lows don't tend to be lower than the mid twenties. Average lows are in the 30's and 40's. But I also wanted to know if the tree could survive 90+ degree weather in the summer.
I am no expert by far when it comes to citrus although I do have an Improved Meyer lemon and a calamondin which I keep in pots outside all year long. I live off the west coast of Canada in a Zone 9 microclimate. The only time I move my trees inside is when there is a prolonged freezing spell, not to preserve the tree but to make sure I don't freeze the fruit that has set. At the moment I have 18 lemons which are destined for lemon pie and quite a few calamondin for marmalade. Otherwise I wouldn't worry about them. I believe that keeping them in pots makes them one zone more delicate. We don't have the heat you have by any measure. A warm summer day for us, on the water is about 80 degrees F. We usually get one or two short freezing spells of a few days to a week each year. Otherwise we don't get frost here.
The Meyer lemon will grow much larger, and generally do much better if planted in the ground. However, being in zone 7 you will have to protect the tree on occasion during the winter. If you are willing to cover and possibly apply additional heat (Christmas lights) during unusual cold spells, plant the tree in the ground, otherwise the tree will have to be in a container. Millet
