Can I grow coffee outside of tropical climate zones?

Question

Sure enough, botanical gardens do grow, for instance, Coffea arabica in hothouses, and, according to Wikipedia, its growth conditions do not seem impossible to achieve in a European or Northern American backyard:

C. arabica [...] does best with 1.0–1.5 meters (about 40–59 inches) of rain, evenly distributed throughout the year.[...] The plant can tolerate low temperatures, but not frost, and does best when the temperature hovers around 20 °C (68 °F). [...] C. arabica prefers to be grown in light shade.

I have never heard of people having them in their garden and actually harvesting coffee beans. It does make sense to me that it may not be economical to have commecial plantations in Hamburg or Berlin, but say I had a little waste heat and a glass house I could divert that to, are there any requirements that I can't fulfill in the moderate latitudes?

In fact, to me, the above description sounds like you could easily have those trees in lobbies and canteens indoors.

Answer 1

There is one requirement you can't fill which would be difficult to get round - uv light levels. You're in the Northern hemisphere, and these trees grow best between the Tropics of Capricorn and Cancer, where the intensity of light is much greater than where you are.

Would be an interesting experiment to try, but quite often, although we may persuade this type of plant to grow in the north, getting it to actually fruit usefully is another matter.

Answer 2

When I maintained tropical plants for a living I dealt with a few coffee plants. They got to about five feet (~1.8 m) tall and looked very attractive with their glossy leaves. They grew as a clump of stems and under the right conditions would flower and set fruit (beans).

Unfortunately the yield was low and the quality was poor for coffee. You might get better yield in a greenhouse with some shade in the summer.

The quality of the beans might have been due to poor roasting techniques as there is a lot to know about preparing coffee beans.

If you just wanted to grow them as an interior plant I recommend them. When they are smaller they do not tolerate drying out. They should not be situated in a direct southern exposure as this is too much sun.

The usual soilless potting mix works quite well for the one I'm growing now in my home. I have not seen any pest problems.