Hello all! So glad to have found a community that might be able to help me! I live in Montreal and have purchased a calamondin tree (roughly 5 years old) in September 2020. The man I purchased it from kept it outdoors all summer and over the colder months kept his citrus trees inside, in a garage where he claimed they go dormant. (Never heard of this, if someone wants to confirm!) Since then, I have kept the tree indoors, at a west facing window & it gets a lot of sunlight. The temperature of our apartment is 22c and we have a humidifier that keeps our place between 25-35% humidity. The tree is not near any heat emitting source. We have repotted it once, into a pot that is maybe 4 inches larger (diameter wise) than the last. We have added some potting soil. When I first got the tree, it had upwards of 100 green fruits on it. They all ripened and we harvested them all about two weeks ago and made a delicious calamondin themed meal! The tree has been continuously losing leaves since I brought it home, however much more in the past month or so than at the beginning. One side of the tree is completely bare! Any ideas or guidance is welcome! I don’t want my tree to die!
Welcome to the forums. I suspect the tree is not receiving enough light and is slowly starving. Note the dead branch is farthest from the window. Try moving the tree as close to the window as possible and rotating the pot a quarter turn regularly so that the foliage receives equal exposure to the light. Note the tree will need less moisture during this time of year, particularly with the loss of leaves; allow the soil to dry somewhat between watering. Does the container have drainage holes? Citrus trees do go dormant; root activity slows at lower temperatures and ceases once it drops to 13C/55F.
I agree with "Junglekeeper": the plant probably is not getting enough light. Our first Calamansi tree died when we brought it indoors for the Winter. We bought it from a local nursery. When days stayed above 12 degrees Celcius, we put it outside in the sunshine, but brought it back indoors for the nights. When the nights stayed above 14 degrees Celcius, we left it outside full-time--most of the summer and a good part of the Autumn. It seemed to be thriving and produced many fruit. As the days got colder, we started bringing it back inside for the nights. As the days got even colder, it stayed inside fulltime. Unfortunately, it died over the Winter. The house temperature was fine. It got water, fertilizer, care, etc. But I am pretty sure it wasn't satisfied with regular house lighting. All the leaves fell off and the branches were brittle. It didn't come back in the Spring. So we bought another Calamansi tree a couple years ago. And we also bought a tall lamprack and a grow light for plants. We just went to Home Depot and picked up the least-expensive lamprack available. And the tree didn't die when we brought it inside for the Winter! It survived the Winter!! This past Summer, we repeated the routine of gradually putting it outside as the days warmed up, and bringing it back inside as days got colder. It did well, and we got many fruit. We put a tomato cage around it, to give it some support, but it is stretching out a little. It is presently inside full-time. I have attached a couple photos. It is against the patio window, which is North-facing, so it doesn't get direct sunshine, unfortunately. But we turn the grow light on for 12 hours a days, around 6 am - 6 pm. We have a mechanical timer for turning power on and off, which is pretty handy. (Originally purchased for the light in aquarium. ~$10) Whew! After saying all that, I recommend you get a grow light for when it's indoors.
An update: The Kalamansi tree is still doing well. It has been outdoors all summer, getting lots of direct sunshine. Gave it some plant food this Spring. Attached is a photo I took this afternoon. It has a few fruit on it, and continually flowers, so should get a few more. Now that the nights are getting colder, we are bringing it indoors for the night and putting it outside during the days.