Hi. I'm trying to do the same with my mango. Since i live in central italy, i tink that growing a mango outside is out of question as much as is growing a mangosteen there where you live. I'd like to join the post to share some ideas about what i tought in the last year tempting to solve the problem. First: the soil temp. About 1-2 meters (3-6 feet) under the soil level the temperature is beginning to approach to average annual temperature of your location. This should be easy to know. Mine, for example, is 58,28F So, if you have a annual average temperature that allows mangosteen to grow (grow, not just survive) with just occasionals cold spell, there shouldn't be problems. If you don't, i guess the taproot will stop growing when it reaches the cooler soil. I'm not sure here, but i expect the roots in cold soild to be more rot sensitive, but is just a guess. You shouldn't need to heat the soil if your annual average temperature is high enough because, after a summer, the structure should keep the soil under the mangosteen hotter than the rest of soil. Second: the structure. In my city the winter are pretty long and cold (this year we got 15F, wrost winter in ten years, but not exceptional), but i manage to keep my greenhouse above 34F without additional heat just because i choosed the right spot to build it. It is attached to two concrete walls, one facing nord, the other facing east. Since, for me, cooler winds come from there it really saves a lot of heat during nights. I keep there mainly cactuses but last winter i overwintered mangoes there without any problem. For the mango now i'm building a removable cover with same ideas in mind. I have built a north wall with concrete blocks filled with dirt (to increase their termical mass and help them retain solar heat). Then i'll build the north side of the roof with some rock wool panels. The north side will have the 45 degree inclinatin to keep it close to a sphere (the sphere minimizes surface/volume ratio, thus the dispersion) and because at this inclination, at my latitude, it starts to do a shade in the structure just after 21 march, when solar heat is not needed as before. The south wall instead will be in policarbonate, will have 30 degree of inclination (at this inclination sun will be perpendicular to the panel during the cooler days, in january). The principes are the same of a water heating solar panel. To further help with it, i plan to put some drums filled with water inside that structure. During the day they absorb solar heat releasing it during nights. Water is better than rocks because has an higher termal mass. You can find a lot of ideas just googling "solar greenhouses": the idea is basically the same, the only difficult thing is to build it removable. Third: the additional heat. The idea of heating water isn't bad, you just need an acquarius heater. Surely it won't be bothered from humidity. I'm not going with it anyway, because i'm going to imagine that i'll need heat just in few specific hours: and waters takes a bit in heating and, when is heated to the point to quickly transport heat to air, takes a lot to cool down. Plus i'd like to consume as little energy as possible. I guess there are some calculation here to take, but to make it simple i have two suggestion. First idea: incadescence light bulb in series: if you put two of them one after another you'll have less light but they will put out a lot of infrared, wich is what you need. Second idea: there are some lamps just for heating chicks. No light, just heat. Put just a thermostat to turn them on when needed, and this should hopefully keep the tree heated. Just few ideas to add to the talk. I'm a total newbie, and, in the end, i do all this just for fun. I'm sorry for any mispell, english is not my laguage.

If you are going to install a new AC condenser and air handler, then the best option is to spend a little more money and upgrade the condenser to a heat pump. The heat pump would be the primary heat source. The back up heat could be either electric heat strips or a propane furnace. If you plan to use the propane for appliances (stove, clothes dryer, etc.) then propane furnace makes sense. If not then consider getting the heat strips. I don't understand how a boiler could be installed outside if the temperature is going to go below freezing. If you installed it indoors, then you have to look at the costs of a boiler versus that of a the other back up heat resources. Even if you did get a wood fired boiler, is someone going to be able to stoke and clean the firebox everyday the back up heat is needed?

I read your posts and admire your fortitude for toughing it out on your old homestead for as long as you did! You really could write a book! I am reading Animal, Vegetable, Miracle by Barbara Kingsolver and it's inspiring me to want to try my hand at small-scale homesteading again. But I'm wondering if I need to move to a different state. I'm joking/not joking. I'm in the DFW area and I can barely get a vegetable garden to grow between pests and heat. My parents and siblings live in the Central Valley of CA and it seems like they stick plants in the ground, water, and they grow. Are you having better success with gardening in Gonzales?

It's lovely and I think you will use it far more than you can even imagine. A few options come to mind: slipcovered furniture, rattan or wicker. We have a 22 foot sunroom with this set, plus the matching chair-all in a different fabric. This has served us well for 25 years (replaced the cushions/fabric once). Our room is heated but we use it in tree seasons only, which is why I am not showing you a picture right now. It hasn't been opened for the season. Enjoy your beautiful addition! Edited to add: Be aware of the sun damage that can occur and chose your fabric wisely (Sunbrella is one brand.) We have woven Roman shades at all of the windows for that exact reason.