I don't know if this is the case with your trees, but I've had that happen to a couple of my Meyer lemons when I've been lax about fertilizing. They tend to need fertilizing at about twice the frequency as my other citrus. Maybe your Eureka also needs a bit more food than the other citrus. Also, I've not found the yellow leaves to really green up again, at least not much. Usually what happens when they get to that point is they tend to drop the yellow leaves over time and replace them with new leaves. If I've been good about fertilizing, the new ones will be nice and green. So I think if you keep up the better care, the next flush of leaves should be much greener. This post was edited by BarbJP on Thu, Jun 19, 14 at 13:42

thanks for your help. I purchased this with 3 others from Lowe’s mid June and repotted within a week. I put them in galvanized steel pots. I used the miracle grow fertilizer for tomato, fruit and veg 10-5-15 around end of June because I couldn’t find any citrus specific fertilizer. I purchased epsoma citrus liquid feed a few weeks later because early July it was already yellowing and had leaf pattern changes. I’ve been researching about yellowing and thought the liquid would boost the nitrogen. I’ve used the liquid fertilizer per directions with water and feed every 2-3 weeks. I mix liquid 2 doses with Proper water and spread amongst 3 trees so maybe it hasn’t been exact. Question : Did You notice the leaves are malformed, they aren’t symmetrical like my other trees. The other thing I can’t figure out is the yellowing started on lower leaves and is extending upwards. The upper leaves are still green. would that be normal if it was a nutrient deficient? i will try and pick up a ph meter or test Kit this weekend first and see if that could be the reason. Id hate to pull this tree out of pot and stress it more, plus I have no clue what to look for. can You point me to good website or even video that shows how to differentiate good root and bad root. And might have good techniques on pulling this out of soil

The leaves are showing a manganese deficiency. The symptom that a citrus tree produces when manganese is deficient in a leaf is as follows: green veins, AND WITH GREEN BORDERS along the sides of the veins, as show in the picture provided. This is rather common in new leaves. and most of the time the tree will take care of the deficiency on it own. The reason for the deficiency is that manganese is in soil in a very small amounts. The new leaves are growing faster than the tree's root system can collect enough manganese to supply the rapid growth. However, over time the tree catches up. You can foliar spray a manganese solution to quicken the process of reliving the deficiency if you wish,, but most people leave it up to the tree.

Did you notice if there were fruit/blooms on the branches with yellow leaves? FWIW, I agree that coir has 'issues' that require work-arounds if you want to use it as a substitute for peat. One of the issues is the tendency for coir to be high in dissolved solids (salts) when processed in sea water. There are other considerations that shouldn't be ignored when using coir as a significant fraction of a container grow medium. I wrote a short piece that reflects some of the research I did re coir and CHCs, as well as my own experiences while experimenting with it. Peat vs. Coir Sphagnum peat and coir have nearly identical water retention curves. They both retain about 90-95% of their volume in water at saturation and release it over approximately the same curve until they both lock water up so tightly it's unavailable for plant uptake at about 30-33% saturation. Coir actually has less loft than sphagnum peat, and therefore, less aeration. Because of this propensity, coir should be used in mixes at lower %s than peat. Because of the tendency to compact, in the greenhouse industry coir is primarily used in containers in sub-irrigation (bottom-watering) situations. Many sources produce coir that is high in soluble salts, so this can also be an issue. Using coir as the primary component of container media virtually eliminates lime or dolomitic lime as a possible Ca source because of coir's high pH (6+). Gypsum should be used as a Ca source, which eliminates coir's low S content. All coir products are very high in K, very low in Ca, and have a potentially high Mn content, which can interfere with the uptake of Fe. Several studies have also shown that the significant presence of phenolic allelochemicals in fresh coir can be very problematic for a high % of plants, causing poor growth, reduced yields, and chlorotic foliage. I haven't tested coir thoroughly, but I have done some testing of CHCs (coconut husk chips) with some loose controls in place. After very thoroughly leaching and rinsing the chips, I made a 5:1:1 soil of pine bark:peat:perlite (which I know to be very productive) and a 5:1:1 mix of CHCs:peat:perlite. I planted 6 cuttings of snapdragon and 6 cuttings of Coleus (each from the same plant to eliminate genetic variances) in containers (same size/shape) of the different soils. I added dolomitic lime to the bark soil and gypsum to the CHC soil. After the cuttings struck, I eliminated all but the three strongest in each of the 4 containers. I watered each container with a weak solution of MG 12-4-8 with STEM added at each watering, and watered on an 'as needed basis', not on a schedule. The only difference in the fertilizer regimen was the fact that I included a small amount of MgSO4 (Epsom salts) to provide MG (the dolomitic lime in the bark soil contained the MG, while the gypsum (CaSO4) in the CHC soil did not. This difference was necessary because or the high pH of CHCs and coir.) for the CHC soil. The results were startling. In both cases, the cuttings grown in the CHC's exhibited < 1/2 the biomass at summers end as the plants in the bark mix. I just find it very difficult for a solid case to be made (besides "It works for me") for the use of coir or CHC's. They're more expensive and more difficult to use effectively. The fact that some believe peat is in short supply (no where near true, btw) is easily offset by the effect of the carbon footprint of coir in its trek to the US from Sri Lanka or other exotic locales. That's the view from here. YMMV Coir Study: https://sites.google.com/site/plantandsoildigest/usu-crop-physiology-laboratory/coconut-coir-studies Al