The trees still get plenty of direct light, albeit behind double glazed windows. Perhaps that glazing, along with the cooler temperatures from outside, help in preventing the leaves from overheating.

Interesting. I had my plants at a temperature of about 15°C so I can only see one option: moving them away from the window.
If this turned out having good results that would be kinda strange since your room was probably colder with more light which should have a higher change of leafdrop than my citrus. strange it is...

When you think about it, there are in-ground trees exposed to similar temperatures (say 10C) and they don't suffer winter leaf loss. (Why is that?) With the door closed the room is sealed off from other rooms. And since the windows are always left open maybe it's better to compare the room with something like an attached greenhouse. The humidity in the room is med-high, which I think is unusual for an indoor environment; maybe that has something to do with it.

According to Dr. Manners in warm citrus growing areas such as Florida, the soil temperatures never falls much below 70F. - Millet

Sven_limoen, I don't understand, what does water have to do with anything? - Millet

I think the lack of water can sneak up on you any time. I also think the citrus in Rome shed a lot of leaves in the winter but outside you don't notice it as much. It ain't easy or everybody would be doing it. Tom

Actually, the amount of water in the ground, or in a container, never causes a problem. The problem is always the quality of the drainage, which when the drainage is poor it causes a lack of soil oxygen. It is the deficiency of root zone oxygen that actually damages or kills a tree, not the amount of water. If the drainage is excellent one could apply all the water they wished, even daily, with out a problem to the tree. Water is the single most important ingredient a tree receives. - Millet

You are not a problem. The tree does seem to be doing real well in Rome. Are you ok ? ) Millet is as good as it gets with this stuff and I think I know what he means about water. What I mean is if you neglect to water enough in the winter or summer your citrus can get in trouble. Lack of water was the biggest limiting factor on our farm because it was not economical to irrigate the crops that we grew and sometimes we did not get adequate rainfall. Tom

I have been to Rome numerous times, and have seen the citrus trees. Correct me if I'm wrong, but I seem to recall most all of the public citrus trees around the city are just Sour Orange trees????- Millet

I have a satsuma indoors and it seems to have done fine for the few months I've had it. It's by a large south facing window. The room drops to about 15c at night but can be about 20c in the day.

Radoslav wrote:

temperature around 10 Celsius during winter.

Not sure how I can achieve this.

Quote:

Theoreticaly, you can keep all citrus indoor, (those grafted on poncirus do not like indoor conditions at all).

My satsuma is grafted onto this. I did worry a bit about it when I bought it, but no signs of it suffering yet. I suppose if the roots remain cool it might be ok.

Millet wrote:

WLD results from a ratio of sun shining directly on the tree's foliage, and the temperature of the root system. No direct sun, not much heat needed (no growth). Lots of direct sun, then heat root heat needed or WLD will result. - Millet

What is WLD? I've noticed on sunny days my satsuma has been getting sticky leaves and it making the table below it sticky. I didn't think much of it since citrus come from hot climates anyway.
Should I be concerned?

WLD = Winter Leaf Drop

The sticky leaves on your tree has nothing to do with sunny days, your tree has a bug problem Check you tree carefully. - Millet