Peters is used dissolved in water and applied to the root zone. 

What Lebmung wrote, cold can be a possibility in certain sections of the country, but not in an area such as San Diego. As to the fertilizer, I personally would not use it.  Citrus are heavy feeders, more so than many other plants.  I use a fertilizer with a NPK percentage of 25,5,15.  Meaning 25%N, 5% P, and 15% K.  Note: this is a 5-1-3 nutrient ratio fertilizer.  According to the text book Citrus, and University research,  this is the ratio that citrus absorb nutrients.  Lastly, besides the low level of the elements NPK, many of the nutrients in your fertilizer example are oxides, instead of being sulfates. 

The discoloration of your tree's leaves are not due to seasonal changes.  It certainly looks like deficiencies of iron and nitrogen.  The deficiency leaf symptom for iron is:  NEW leaves with green veins on otherwise a yellow leaf.  This deficiency can be caused either by high pH  or the shortage of minerals.  The leaf symptoms for a nitrogen deficiency is: Totally yellow leaves with no variation of color, or yellow/orange veins with some green out on the leaf sides.  Nitrogen is highly soluble, and thus is quickly leached from the medium with watering. For a container grown tree, growing in a rapidly draining medium, the tree should be fertilized at the very least once a month.  Once ever couple weeks would be much better.  Locate a water soluble fertilizer with higher levels of nitrogen and potassium and a lower level of phosphorous. Be sure the fertilizer also contains trace minerals.  It is difficult to see your tree's medium, as it is covered with dead laves.  What is the makeup of the medium mixture that the tree is presently growing in?

Brian, the high CO2 should greatly help the growth of your trees.  Commercial greenhouses  install CO2 generators for exactly this additional growth,

It is easy to determine the difficulty your tree is having.   No fertilizer all summer is not a good situation. without fertilizing the tree certainly will become deficient of the vital minerals required, thus is incapable to producing any growth., Using an organic fertilizer in a container, such as Citrus tone, is also not a good situation.  Organic fertilizers require microorganisms to break down the organic fertilizer to make it usable to the tree.  Container mediums do not have the microorganisms required to accomplish this.  Be careful purchasing Miracle grow as the product is different in different parts of the country.  A 50/50 mix of Turface and Miracle Grown Garden Soil is also a very good medium for container culture.  Miracle Grow Garden soil is different than plain Miracle grow  potting soil.  Also a 5-1-1 or a 5-2-1 mix is a good medium. I would recommend using a conventional fertilizer with higher levels of nitrogen and potassium and a smaller concentration  of phosphorous plus with trace minerals. Good luck to you and this tree.

From looking at Ilya11 picture there seems to be very little pulp, and a lot of thick peel.  Therefore, its use as a lemon is greatly reduced

I pick them as I need them.  Anywhere from 2 weeks to a month or so.

In Japan Shiranui (Dekopon) is harvested between December through February.  Here in Colorado (greenhouse grown) the fruit on my tree began to color up 3 weeks ago, and today are fully yellow.  I ate one several days ago, and it was good, but not as sweet as it should have been.  I am going to leave mine hang for a while, and taste again in a week.  Know that the Japanese growers let them set after picking for 20 to 40 days wrapped in paper to let the acids reduce and the sugars increase.

https://www.ijeas.org/download_data/IJEAS0207025.pdf

I have an in ground Dekopon tree in my greenhouse.  The greenhouse is at 5,440-ft  elevation (1,658 M).  Day  temperatures are around 70F during the winter when the sun is out, and the temperatures is set to maintain a 55-F night temperature.  Under these conditions the Dekopon's are now most completely yellow.

lebmung, you don't cover your seeds with a layer of the medium?

The old saying is true....Good things come to those who wait.

As written above citrus seeds do not transmit HLB, also  none of the true virus diseases (Tristeza, psoriasis ect.) . are also not transmitted through the seed.

I have been hearing a lot about the use of rice hulls in general nursery culture of bedded plants.  I am very interested in experimenting with rice hulls in the cultivation of citrus trees.  Doing tests such as the length of time before the hulls begin to deteriorate, root zone aeration, etc.