you would need to bring it in the house for overwintering, extra light would be great.

I don't know specifically about pommelos, but I agree, extra light would likely be helpful, even if you have a nice sunny window.

What sort of temps do you have in the house?

I was assuming that you would be summering your pommelo OUTSIDE. Inside, I doubt there is enough light unless you have big window facing the right direction. Where in Canada are you and what are your average summer temps like? (You can provide in Celsius; I can do the conversion.) Temps in the 80's by day and nights in the 60's should be mild enough for fruiting and flowering.

P.S., For those of you that have not tried growing pommelo, I can only say that they perform fine in containers. It is one of the few I have to bring into the house (and not leave in the garage), as they are not that cold hardy compared to other citrus. They seemed to overwinter indoors better than the oranges I used to bring indoors. I grew mine from seed from a store-bought fruit and even that seemed easier than other citrus.

Thank you everyone for your help! I can grow it outdoor during summer time (from May to September). The average temperature is around 22 to 30 celsius. After that, I must bring it inside my house. I will have two options for winter: in front of my south window or grow it in my basement with artificial light (led). I think my chances to have it flower and fruit are very slim here...

Amy, I used LED bulbs all winter and they worked incredibly well - and are very energy efficient. I used 23 watt led 6500K. You can buy them on Amazon - $12/4 bulbs or thereabouts.

Hi Laura, I saw in another post that you have a valentine pummelo and that you winterize it in your sunroom. Did you get any fruit? What is the day/night temperature in it?

Amy, I do have one but only got it a few months ago so I've not overwintered it yet. However, I overwinter all my citrus in my house (most in my sunroom) with those led lights and lots of windows. The LED lights heat up the room well enough so I think I only turned the heat on in there once last winter. However, I live in Maryland - way south of you. Temps in my sunroom in the day are around 60-70 and at night, they hovered around 50. The trees grew quite well and although not a valentine, I did overwinter there a cocktail grapefruit and oro blanco, both of which did well.

Laura did any of your grapefruits or oranges ripen? If so, how was the taste? I only had tangelos and lemos that were great but no oranges or oro blanco. My valentines are as small as yours and will take at least three years before I see any fruits.

Susanne, I do not have any ripe grapefruits or oranges yet. My trees are still too young, but a few do have fruit. The red grapefruit has five fruits - three of which are getting bigger by the day. The oro blanco has three large ones. I have a cara cara that has almost a full size orange (small tree), and a couple on another small tree. My sanguinelli has four nice oranges, but they are not large enough to ripen yet. I also have a moro that has an orange, again, too small to ripen yet. I plan to leave the blood oranges out a bit longer than the other to stress them a bit so the oranges turn color. We shall see. I think that I have enough heat here in MD for them to ripen - the summers are sizzling and humid. Also, in my sunroom when the trees are inside, they get lots of light and heat from those artificial lights. Sometimes it gets so warm that I open the windows ;-)

My valentine had a fruit on it, but I cut it off a few days ago. The tree is just too small to support a fruit that size and I'd rather it spend its energy growing. Here are a few of my ray ruby grapefruits:

I can't really add much insight to the heat requirements of the Valentine because my summers are pretty toasty out here in the plains--Friday will be 38°C (101°F) with a dew point north of 26°C (79°F). Yikes, damn corn!

If I had to make one suggestion, though, I'd say it would be worthwhile picking up some grow lights for the winter. My trees actually put out ~2 flushes over the winter! My only warning is that the winter growth needs to be acclimated to spring sunshine early on or else it'll get sunburned.

Also, make sure your Valentine stem gets at least 2-2.5 cm in diameter before keeping fruit because the they get quite heavy (and large). You probably don't want it growing like the St. Louis Gateway Arch!