Need advice

Hi-I am Patti Marshall, growing a large 48 yr old citrus in a pot in Nashville TN. I re-potted it last year, housed it in winter, and it did very well until recently, when I have notices leaf drop and some branch death. I think it is draining adequately, but know that is a concern. The pot is very large, but has numerous 1" holes in bottom. The branch death is on one side-and I have begun to spray it, thinking pests might be a problem. Some of the dropped leaves have yellowing in veins. Could nutrition be a problem? It uses its fertilizer very quickly, as frequent watering may wash nutrition out. Any ideas are appreciated. I am a new user to this web site, and also appreciate any suggestions about how to best use it. Thank you.

Patti, It sounds like your tree is having some root problems I would suggest that you have a look at the 1 inch opening on the bottom your container to see that they are not plugged up. The water maybe holding on one side of the container.

When repotting did you use a porus mix that drains. some potting mixes hold on to too much water.

repotted (only sides accessible due to size of tree) yesterday-old soil was relatively dry, very lossse. Susptecting that nutrition is also a culprit--have relied primarily upon potting soil for nutrition, but it is wearing out annually now due to size of tree--any advice for a nitrogen rich fertilizer, especially liquid, would be appreciated. Commercially available citruc products limited in Tennessee. Thanks for any advice

I order bags of fert's from this company. Only because I can't find them in my area. The shipping can be a bit costly, but I get what I want. I've never received a broken bag due to shipping, and they do not sit on the orders making you have to wait. Many of the fert's contains the needed Micros for citrus. The also sell S.T.E.M. made by Scott's.
[Only Registered Users Can See Links. Click Here To Register...]. Best Always. Dale

My Two cents worth=Try to get either a slow release fert or soluble fert with as close to this formula as possible= n 5 p 1 k 3 plus 7 minor nutrients.Try to avoid urea as a source of nitrogen if possible.
Citrus always absorb npk at this ratio.A high nitrogen figure is good,mine is n 15 p 3 k 10 plus trace elements(pretty close to ideal formula)only 5 % of that nitrogen is from urea.Dont bother with organic soluble liquids( if you must blood and bone once in a while would be ok).The trick is to try to feed 2 weeks before anticipated growth eg very late winter and late summer.so just before spring and autumn with the slow release ,then only feed when you see new growth.Dont feed when dormant or for at least two weeks after a transplant(i reckon,wait until you see new growth).repot ever two years and root prune/top prune/add fresh mix.
Personally,i like to go half strength slow release with blood and bone powder mixed into fresh mix for the top 4 to 6 inches at the start of the growing season eg spring.Then liquid feeds every two weeks with a soluble fert. Little and often is better,than a lot at once.You might want to check your ph level too.
I tend to agree,it does sound like drainage.Try adding a whole load of perlite to your mix too.My middle name should be "perlite" as i am always singing it praises!!A screen at the bottom of the pot will stop the drainage holes from clogging.I find onion bags,cut up are very effective.
Thats a bloody old tree,very important it makes it to 50!!! good luck.The most important thing right now,is get the drainage right.Perlite is awesome= stops compaction,aids drainage,adds air space for healthy root growth(try to go 50/50 perlite and soil at least.I have mine in 70/30!)Make the top inch potting mix only,so the perlite wont come to the top or blow away in the wind.This mix will be lighter and easier to move that big pot!For now,you could just repot in the mix suggested and leave the feed alone,until the tree starts to recover.Wait for new growth,let it get going and then feed lightly.(be patient) cheers