I overwintered this kumquat in the house . It was fine, and even gave me a dozen or so lovely little fruits. Then after the fruit ripened and was picked, it slowly started to deteriorate. The leaves began losing colour - not dropping though. I fertilised and transitioned it slowly outdoors when the weather warmed up, but it doesn't seem to be improving. I can't see any little critters on it, no spider mites. HELP !!! Stephanie in Virginia USA
Citrus needs to to be fed with a fertilizer that includes micronutrients or trace elements. Are they present in your fertilizer? By the way the recommended NPK ratio for containerized citrus is 5-1-3.
You may want to flush the container several times to remove the previous fertilizer before adding the new one. Also, have a look through the following document to confirm a deficiency: A Guide to Citrus Nutritional Deficiency and Toxicity Identification.
