Carambola show water stress when they are real thirsty. If you look at them the leaves fold to conserve moisture. Generally they should NOT get that bad.

Yellow leaves are normal drop off for even a healthy happy carambola. For watering guidance, most recommend wiggling a finger into the soil, if it's dry 1+" down, water the plant.

Mine always turn yellow when overwatered. Even here in Phx Im watering container starfruit about every 4 days, and its 110. These seem to like to dry out about between waterings. They get a little wilty when needing more.

Hi Sarah,

I hope you find this post--I was reading 3 pages into this forum when I saw your question. I had the same thing with my Bell cultivar starfruit. Leaves were turning yellow on a nearly daily basis, and I also had leaves that became yellow or white in between the leaf veins. The tree was growing very well, putting out new leaves and branches, but it was fighting to produce more leaves than were dying.

It took me awhile to discover that the pH of my soil (sandy, south FL) was to high. Carambola like moderately acidic pH soil of 5.5 - 6.5, and my soil was 8.1! The strange white leaves were caused by the tree not able to get nutrients from the soil, the pH was so high. When I added some soil acidifier from Home Depot (as in the instructions, enough to lower the pH 2 points), the yellowing of the leaves stopped after 1 - 2 weeks and no new leaves became white.

By the way, you will have to add the soil acidifier regularly, as there are microbes in the soil that will gradually raise the pH again. I just add more acidifier when I see some leaves turn yellow again.

i got a potted kari also, but only have yellow leaves about 10% of the entire tree. As for fruit drops, i'd say it's between 1/3 to 1/2 ratio, but i still have about 8, 9 fruits now that are about 4 inches long dangling on the tree. And i water it about every 2, 3 days here in zone 9.

I finally figured out, sort of, what the problem was. It was something with the soil - I think that the soil didn't drain well enough and the roots were sitting in too much water. I took the tree out and put a better soil mixture in the pot and repotted, and now it seems fine. When I inspected the old soil, it was muddy and spelled bad. Happily the tree is now growing like crazy and has had very few yellow leaves and no fruit drop since I changed the soil.
Thanks for the responses!