Growing a coffee tree in an attached greenhouse?

Assume I have a room with a large south-facing wall that is all or mostly windows, like the greenhouse of an Earthship.

Could I grow a coffee tree in a large planter in this room? Or are there other factors like elevation and stuff I can't control that would necessarily affect its ability to grow?

(BTW, is growing a single coffee tree worth it if you want to be able to grow your own coffee?)

Funny you should ask, I've been growing some coffee trees as houseplants and was wondering if they can produce coffee now they are getting quite big.

Apparently,  according to random youtube videos,  2 pounds of roasted beans is the top performance for a mature coffee houseplant.   Under one pound is more usual.

I haven't found out if we need two plants for pollination or if one will do.  I got extra just in case.

My own observations are that they don't like going below 67F and that they are extremely sensitive to the short days we have in the winter this far north.  I'm going to need to get some grow lights to stop them loosing their leaves. But here we also have to shake the chickens because the days are so dark.

Another advantage I found is if I fill the south and west windows with leafy plants like coffee in the summer,  they act as a wonderful insulator to reduce the amount of heat the sun puts in the house.

Coffee seems especially good at this as it loves the heat.  I worried the sun would damage the leaves but it doesn't seem to if the plant can adjust slowly.

I've grown coffee as a houseplant a number of times and they always seem pretty happy, but every time I've put one out into the greenhouse, they die a pretty quick and horrible death. I don't think they are at all tolerant of the colder overnight temperatures (my greenhouse is regularly in the upper 30s (°F) and at best in the 40s for most nights in winter, and it only takes a month or two of that to kill even a sizeable, healthy coffee plant.

I've heard the trick to getting them to flower and fruit is actually to briefly expose them to cooler temperatures (maybe take outside in part shade for a week in spring?), once they are large enough to flower. Someone on another forum documented this for one he'd grown indoors, but he planted all the seeds rather than roasting them since it wouldn't have been much, and coffee requires a special fermentation to really be good quality, which is hard to do in small batches.

They do not generally need a second one for pollination, though.

i have a coffee tree and it has a couple berries on it now but not many
in the past i had enough berries to make a cup of coffee but i botched the roasting process
i used a frying pan and flipped them around but the ended up burnt on the outside and raw in the middle still
my next good batch of beans i will roast them in an air popper for popcorn to get an even roast
all the times i have gotten fruit was during the winter when the tree was inside and under lights in the basement for the winter

mine is about 5 feet tall currently.. not sure of the exact variety
i have had it for at least 10 years and it has fruited several times
this is in toronto canada

Popcorn popper could work, or not.  A few will do OK out of the box, some will be fine once some overheating protections have been disabled, some are pretty much hopeless.  I believe later models tend to be in the last category.  I roasted a fair amount in old poppers made by the Wearever Aluminum Company, if I remember right.  Typically yellow and white.  I think I had to hotwire all of them, the procedure depending on which model.

A simpler and maybe more reliable way involves a heat gun, of the kind people use to set their wood siding on fire while trying to remove paint, a steel bowl, well insulated gloves and a large spoon.  Keep it going while you hear some loud popping noises, which should die down, and then some smaller crackling sounds signal completion.

Coffee is an excellent house plant because it tolerates some shade.  I managed to get a few beans, which I planted.  I'm no expert, but I expect they were of very low quality - well, I know they were, because good quality Coffea arabica is grown under very specific climatic conditions that aren't going to be reproduced inside the home, including but not limited to very high elevation.  Other species - C. robusta or C. liberica could be a better bet.  If I had somehow managed to grow a useful quantity of them I'd have roasted them anyway.  The processing problem is less the fermentation part - I don't think they do that everywhere - just dry them, but they have kind of a shell that needs to be milled off, which for a large quantity would be kind of a nuisance.

The problem you're going to run into is the viability of growing arabica varietals at elevations under 3000 feet. Leaving varietals aside for a moment, the best-tasting coffees are classified as strictly hard bean (SHB) and strictly high grown (SHB). Like cacao varietals, not only is elevation a factor, but also the soil, climate, humidity, and other factors. They all contribute to unique flavors in the final product. Like the bright, fruity taste of Kenya AA or the brooding deeper tones of Sumatra. Then comes processing and roasting levels (light, medium, dark) and techniques (drum roaster vs. fluid air bed roaster). They all work together to determine the final taste in the cup.

Bottom line is if you're not growing coffee at significant elevation, it won't achieve anything near specialty coffee standards in the final product. What will grow well and produce at lower elevations is the robusta varietal. What does it have going in its favor? Much higher levels of caffeine than arabica varietals, and richer crema. That's about it, and for some people, the higher caffeine content could be considered a downside.

Robusta beans once processed, roasted, and brewed produce a nearly flavorless, even insipid yet highly caffeinated cup of coffee. In the industry, they're mostly used in sodas and energy drinks, or to boost the caffeine content of darker roasted espresso beans. And it adds body to the crema in an espresso.

If you're simply wanting a conversation piece, and bragging rights that you grew, processed, roasted, and brewed coffee from plants you grew yourself, you can do that. I'd be impressed. And you could use the beans to make a better espresso by mixing them in with dark roasted arabica.

j

I can't imagine the goal is to make the best coffee ever.  

I grow a lot of food that is less than perfect.  Growing it myself adds something to the flavour that makes it taste better than the store-bought stuff.  

And maybe, if I like the coffee from these cheap - 20 seedlings for $3 - coffee plants, I can invest in some better quality seed.