Hello..
I have posted before that my Calamondin tree was dropping leaves after the veins were yellowing. Since then the Calamondin almost stopped dropping its leaves, but lost quite a few. Now its losing one-two every week.

My new problem is that this behavior "moved" to its neighbors: my Meyer lemon and my Buddha's Hand tree. My BH even dropped some fruit but no leaves until now. Today I noticed that each tree had some leaves with yellow veins so I tried to shook them and each one dropped more than 20 leaves each (old and new, with the petiole and without it).

There are more (a lot) leaves left in the tree that are showing signs of vein yellowing. I am getting worried.
More than that my Meyer has stopped growing it's lemons for a while and they are stagnating.

What can I say: since autumn is here the temp has dropped to 77-80F (25C) and the level of light it is not the same.
More: I noticed a red spider mite infestation on both of them. I took some measures and I think it worked but maybe it didn't.
I fertilize them every week.

What do you think? What can I do?
I attached some pictures with the leaves and with the Meyer lemon tree.

Be absolutely POSITIVE you eradicate the spider mites. Horticultural oil (Volk, Ultra Fine) work excellent controlling spider mites, along with mealy bug, aphid and scale. Get a soil thermometer and keep the growth medium (potting soil) at least 70F until leaf drop stops, then around 64F (21C). Millet (1,211-)

10 more leaves from each tree.. More yellowing going on. Pot soil temperature is around 81F. That is the stable temperature.
If somebody has a diagnostic. When the veins are yellowing and the rest of the leaf is still green?
10x!
More pictures!

The common symptom for nitrogen deficiency is yellow-orange leaf veins with some green on the leaf sides. Nitrogen deficiency shows up on the older leaves, with the newer leaves still green. Otherwise I don't know. - Millet (1,210-)

I fertilize them every week with liquid fertilizer: 6.2%N, 6.8%P, 10.9%K,0.2%Fe (Iron) and Mg,Zn,Mn,Cu,B,Mo in a 0.001-0.02% ratio. It seems strange that it shows N deficiency sign because of that.

Today I fertilized the trees with a higher concentration solution but I hope I didn't burnt the tree.
What can stop the nutrients to be absorbed by the tree? High Ph or the rong soil?

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Also I have a cutting lemon tree that for 6 months now has stopped all growth. I gave it everything (sun, good soil etc) it needs it has but it refuses to grow anything. I think I am going to toss it to the trash bin.

What is the pH of the water you use? pH of your soil? Citrus prefer a slightly acidic root environment.

Did you use pine bark or wood chips in your potting mix?

When pine bark or wood chips are breaking down they use alot of nitrogen in the degradation process, thereby making less available to your plant during that time.

to me it seems that your nitrogen content is to low , they say that a 3.1.1 ratio is the best so your ratio is way off in my opinion

David, is that typo?
Recomended ratio is 5-1-3.
link
Let me cite
"The absolute VERY BEST fertilizer for containerized citrus trees, is manufactured by the J.R. Peters Company, under their Jack's trade mark. The formula is 25-5-15 W/trace minerals, which provides the perfect 5-1-3 ratio, which is the ratio of nutrient uptake absorption by citrus roots. Absolutely none of the nitrogen is derived from Urea. It is sold in 25-lb. bags, which I purchase from their distributor in Denver, Colorado. J.R. Peters has distributors throughout the United States. They are the #1 supplier of fertilizer to the U.S. greenhouse and nursery industry. An amazing fertilizer for container citrus.- Millet (1,277)"
from:
link

ivica, your correct, 5-1-3 is the ratio that citrus roots absorb nutrients. The yellow veined leaves that you show in your pictures, are these the older leaves? At this time of year a lot of citrus leaves turn yellow and drop from the tree. . There is no welfare program for citrus leaves. When an old leaf is no longer capable of manufacturing its full quota of photosynthates, it is discarded. I have 100+ varieties of citrus, all but 7 are in containers. Many of my trees are presently discarding old leaves that look like your leaves. A citrus leaf lasts about 18 months. . - Millet (1,156-)

By now they have stopped falling. I still get one or two a week on every tree but nothing to be scared about. This winter I am keeping them in a room with central heating so it is a miracle that I don't have more trouble. 4 months to go so maybe I am speaking to early. I have some trouble with some spider mites but nothing to worry about.
Today situation in pictures:






About the fertilizer. This is the ratio I find in my country for citrus. Every kind of citrus fertilizer (it says citrus on the bottle) has that kind of ratio.
So I can't do nothing about that.