I'm no expert but since you are already using 7-3-3 which has Nitrogen, your trees appear to be lacking Minor and Trace elements. I would simply go the your local nursery and look for a fertilizer that has Minors and Trace. From the looks of the first picture though, for some strange reason, it does appear that your tree still lacks Nitrogen. I say this because the larger older leaves are more Yellow where as the younger smaller leaves in the picture appear more green which is usually a sign of Nitrogen deficiency.

For a really quick fix, go to your nursery and pick up some water soluable Miracle Grow 20-20-20. It has Minors and I think Trace minerals. Just follow the instructions and if you foliar feed, you should notice a change in color within a couple of days.
Simon

What else do you have growing in that pot? Citrus are very poor competitors; so if you have other plants, they will steal the food.

Two things I know of that cause such yellowing; lack of food and/or over watering.

I recommend re-potting them in a coarse, well drained medium (There are many references on this site to types of citrus potting medium); make sure your pots drain well, add more fertilizer (most potted citrus need to be fed at least 4 times per year; or as some prefer, every time you water... sometimes called "weakly weekly"). After that I would find a good foliar fert (I use Bayer Bayfolan Forte for my garden trees; but there are others as good) and apply the foliar every 15 days. If you are not overwatering, you should see results soon.

Same thing happens to my potted citrus and the culprit turned out to be HIGH Ph water. I lower it down to 6.2-6.6 and added trace elements with iron and the problem began to go away. Do a test on your tap water. I know some cities will come out and test for free but you can buy a Ph test kit from home depot. If your real serious and what I recommend is a Ph test pen (meter). At first I added 1 tbsp of distilled white vinegar per gallon of water to lower about a point but then I went out and bought a product called "Ph Down". You can get it at hydroponic store or google.

Also correct is that citrus hate competing for nutrients! My in ground navel was worse than your so I dug out the grass from around the base and topped with some lime and cow poo and covered with pine chips and now the tree looks nice!

Citrus dont like alkaline soil and competition.

San Francisco water comes from Hetch Hetchy dam in Yosemite Park; it is snow melt, essentially pure and pH neutral, so I doubt that is the problem. Since the plants are in pots, I doubt the problem is pH of the soil.
As for fertilizers, on the organic side, cow manure is near perfect for citrus; chicken manure is much less than perfect.

natayam,

To answer your question, you'll want to look for the micronutrients Iron, Magnesium, Manganese, Zinc, Calcium, and Sulfur. I've used GreenAll's Citrus & Avocado fertilizer applied on Valentine's Day, Memorial Day, and Labor Day following box's instructions very successfully here in the Bay Area.

Tim

Apologies. The fertilizer I state above is used for my in-ground citrus (which may work fine for containeriized trees, but haven't tried).

For my potted Meyer lemon, I use 1/2 tsp Foliage Pro + 1 capful white vinegar per gal of water (I agree with John that SF water is pretty amazing!) at each watering. Foliage Pro is fantastic and has all the essential and micronutrients that a citrus needs!

Tim

OOps re reading my post I added sulfur not lime. Sulfur..lol

Oh and johnmerr.

Just because its mountain water with a "neutral Ph" does not mean that the water agency does not artificially or chemically raise the Ph to be less corrosive on the pipes. The water can still be soft and pure and have high Ph for one reason or another.

I know people in the bay area with water OVER 8.0 Ph. Why? Who knows.

What did you do Johnmerr? Do a quick google search on the quality of the water in San Fransisco after reading my post and read a quick snippet of a soundbite stating that the water is in Hetch Hetchy reservoir just to try and discredit my post...lol Oh wait I forgot, you have 8000 lemon trees.

My mandarin looked EXACTLY like the ones in the pic. I lowered my Ph and fed some micro-nutrients and the plants perked up. Im not saying she has high Ph water but without a test, YOU, me and the rest of the world will never know.

You cant rule anything out until you have tested to make sure.

Hi Everyone,

Sorry for disappearing for a week! My computer got virus and I ended up formatting my hard drive and had to re-install everything. My computer is just alive this afternoon after all hard work.

Thank you everyone for your input. Talking about my citrus trees, 2 of them got worse. I will re-pot them. I just learned from this site about gritty mix (Al's mix; 1 bark: 1 turface: 1 granite). The only thing that I got so far was orchid fine barks. I went to many places this evening and I still couldn't get turface and granite. Somebody mentioned about "Ewing irrigation" carries turface. I will try to get them tomorrow.

Johnmerr: I didn't grow anything else in the citrus pot. From time to time, there are some weeds in the pot. I pulled them out but still have tough roots in there. I don't know how to permanently get rid of weed. And you are right, I have to put fertilizer more than 3-4 times/ year. The instructions for chicken manure said " apply monthly from Jan-Aug"

Tim: when you mentioned "Foliage Pro", Do you mean "Dyna-Gro, Foliage Pro 9-3-6"? I am going to order one online.

I have a few questions here:

** If I re-pot them, can I still use their old pots. The pots are still in good condition (16 inch plastic pots). I will clean them thoroughly. Can I clean the pots with soap dish?
** Can I still use chicken manure for fertilizer in gritty mix if I also use Dyna-Gro Foliage Pro?
** Do I have to cut some roots?

I hope to re-pot them by this weekend. Hopefully, I can get turface+ granite soon.

Thank you again everyone. I will post my pics of my trees again. They look bad now. I am so worried.

Have a good night, talk soon

JOJO

Hi Jojo,

Yup, that's the one (Dyna Gro's Foliage Pro)! That's the only thing I use, plus the vinegar for added measure. I would suggest trying this on its own and NOT applying too much/other fertilizers, since it is possible to over-fertilize your tree.

And yes, you can re-use your old/cleaned pot so long as your roots have not outgrown the pot. And if so, you can root prune which will certainly allow you to re-use the pot for many years (think bonsai growing).

I would also encourage you to consider the 5.1.1. mix instead of the gritty - take a look the post below that I just answered which compares the two.

Cheers,
Tim

Here is a link that might be useful: Gritty vs. 5.1.1. mix

Its either getting too much water, but looks more like a lack of nutrient.

I have had my meyers lemon (potted) going on three years now, every spring I top dress the pot (re-potted this spring) with Composted manure and then I spray the foliage and water monthly with compst tea that I make with worm castings from my worm bin and add blackstrp molasses, fish emulsion and little bone meal. It seems to be working because this is year three and she is loaded with fruit!