I don't use straight potting soil here even in S. California where it's pretty dry, as it can compact and retain water at the bottom of the pot. I would use a stick to test the soil moisture. Stick it all the way down to the bottom, and pull it out, and see if the bottom of the stick is wet. This could be your issue. I will mix a high quality cactus mix (I prefer EB Stone's Cactus Mix) along with small bark (such as reptile bark or small orchid bark) along with perlite or vermiculite for a better draining mix. I use more fines (the Cactus Mix) than our indoor container folks due to our prolonged dry and hot weather, and want a little more water retention than our northern container forum members, and this works well for me. I also use a time-release fertilizer with an NPK as close to 5-1-3 as I can get along with all the micronutrients as well, and also water at least once a month with full strength DynaGro Foliage Pro. Your tree looks undernourished, so be sure you're fertilizing it regularly. Meyer lemons for me in my experience seem to need a bit more fertilizer than other cultivars, so I would include a time-release fertilizer such as Dynamite fertilizer, and then I would switch to a liquid fertilizer (which is what FoliagePro is). Vigoro is fine for in-ground citrus, and I use it for my in-ground citrus, but not for my container citrus. And the fruits are using a lot of your little tree's resources, so you're going to see a little chlorosis due to the tree using a lot of its energies in trying to ripen fruit. Once the fruit is pickable, you should see your tree pick up. I'd keep the fruit to a minimum for next season until you see a significant growth in the leaf canopy, which will support fruit production.

Patty S.

It has maturing fruit, baby fruit, is starting to bloom, and probably ready to start new growth; that combined with a probable light change from where it was to where it is now. The tree is in need of more energy, so it is sucking the nutrients out of the older leaves to use for flowers, fruit, and new leaves. I would leave the yellowing leaves on the tree until the midrib is completely yellow; at that point the tree has taken back all it can and the leaf will fall or come off with only a touch.

Why is Vigoro better for in-ground citrus and Foliage Pro (liquid) better for potted citrus? I have made the switch but would like to make sure I understand why. Is it that Vigoro is more likely to have excess nutrients accumulate in the pot than the liquid but easier to disperse for an in-ground tree?

Thank you for the comments. Makes sense that the tree is taking energy from the leaves to ripen the fruit. I just ordered some DynaGro Foliage Pro so I'll see how things go with more fertilization, and also look at the drainage.

Grove, because you won't get nearly the salt build up with a good quality liquid fertilizer like Foliage Pro, as you would a granular product. And, I find the absorption to be better, so I get better results. I use that in combination with a time release fertilizer because our our climate and long, long growing season, and this has been an excellent combination for me (thank you, MeyerMike, for tipping me off to that, really works for year 'round container citrus in Calif.)

Patty S.