well my mom got the tree as a gift for christmas and i kinda took ownership over it. i put it in a shed i have under a 400w hps. it started to drop some leaves about a week of having it and leaves started curling as pictured.The temp is usually about 60-75 day and night. I have a small ceramic heater to supply the heat at night. i know its not underwatered. i dont think that its over b/c the soil drains very well and i only watered when it got pretty dry. when i did water i used an organic fertilizer. The shed is 8x8 and i really dont have proper ventilation yet but i try my best to open it a couple times a day to ler it air out. i have a fan on 24/7 for circulation inside. some of the older leaves also get like a mosaic pattern on them. and some fruits also get strange spots on them. you can see if you look good. i also looked for bugs but cannot find any. my grandma and aunt also got one and all the leaves fell off theirs and maybe died. they think it was due to overwartering.

I happened to come across the post in a google search and just had to say -- how cool! My mother has a calamondin she received as a houseplant while recovering from surgery 10-12 years ago. It's now over 5' tall, and a good 3 1/2' around -- it takes two people to bring it indoors to its winter home! (She lives in southern Ohio) It always seems to have both fruit and flowers on it, and she has harvested over 200 ripe fruit at a time. When I was home a few weeks ago, I picked a lot of fruit which I processed and put in baggies in the freezer, for calamondin cakes in the future. She says the tree needs picking again, so the next time I visit I'm going to pick enough to try calamondin marmelade. Your fruit looks beautiful, and I'm sure you'll enjoy the tree for years to come!

@ John: Fertilizing with Miracid. I use a dilute solution (1/4 tsp dissolved into a gallon of water, which is also supplemented with 1 tsp of fish emulsion) when I water. I've had it 2 months though the tree is 14 months old. In those 2 months I haven't had any growth. I just (yesterday) bought some epsom salts and some iron supplements (including micronutrients: .50% Magnesium, .02% Boron, .25% Copper, 5% Iron, .25% Manganese, .50% Zinc), though I haven't yet used any of this on the plant. @Jean: I'll keep the suggestion for a larger pot in mind. I have a slightly larger pot it can go into at any time if needed. Thanks to both of you for the tips. Fertilizing a bit more might be the first thing to try.

Boy, I don't know. I'm no expert so take this with a grain of salt: There could be a number of reasons why the leaves are yellowing. First off, did you just bring this plant indoors after being out all summer or is it still outdoors? If brought in, the change in light levels, humidity and/or temperature COULD have something to do with it. Also, I would check the roots. If they're healthy, then it could be a fertilizer problem. If they're not healthy, there's no way they can give the plant water and nutrients. I would unpot plant carefully. New roots should be white-ish. If they look dried up and dead, you have a root problem -- most likely from compacted soil, or overly wet/dry soil/ too much heat buildup in the pot. In pots outdoors in full sun, the soil can get really hot and cook roots. You've had a very hot summer in Texas. It's not quite as much a problem using clay pots as in plastic but could still be an issue. Minimum temperatures for root growth in citrus is approximately 54 F, while in controlled experiments, maximum citrus root growth occurs between 78 and 90 F. Much above 90 it slows and I would worry that if your soil temp has exceeded 120 degrees, it may be damaging. To remedy, move plant to partial shade - especially in afternoon. Some people paint containers white on one side to reflect heat. I had my potted plants in full sun on the south side of the house and they started to decline. I moved them to part shade and they took off! In clay, the soil can dry out too fast- especially around the perimeter where the feeder roots are; then they die. Also, regular potting soil can hold too much water, especially in the lower 2 inches of the pot -- then roots die at that level. Even when the soil appears dry in the upper 1/3, the lowest 2 inches can still be too wet. If this is a problem with your soil, consider adding some pine fines to the mix, or coconut husk chips, if you can find them. Also consider growing in a taller container. A taller container is better than a wider container for this reason. I'm wondering if there also may be a salt buildup in the soil from using Miracle Grow/Epsom Salts. Although you've not had the plant that long. So, for what it's worth, it could be fertilizer issues, or it could be a number of other things in my opinion. I attended a seminar on Growing Citrus in Containers and the main point was that 90% of failure has to do with poor root growth -- caused by either too hot soil, or they're not getting enough oxygen. When roots begin to die, the plant will not get enough nutrients and it may mimic a fertilization problem. So look to the roots! Healthy roots make a healthy citrus.