Meyer lemon leaf issue

May not be an issue if only a few leaves. Perhaps this link will help identifying the potential problem, if it is a nutrient deficiency. Looks from the photo like the Meyer lemon is in a container. Container grown citrus does require a bit more attention to detail in fertilization than in-ground citrus. I also grow Meyer lemon and key lime in containers. Often yellow leaf with green veins is an indicator of a micronutrient deficiency, such as iron or magnesium. Use Epsom salt for magnesium deficiency, Iron Sulfate for iron deficiency. Apply as a solution, not dry.

Nutrient Deficiencies in Citrus

pH meter - that is good question, and as a person that comes a science background, with a reasonable amount experience in soil and water chemistry, I’ve looked into this on occasion and I’ve not been able to convince myself there are any good, reliable accurate cheap meters/probes you can stick into your garden bed that will give you consistent, reliable pH readings. I wish someone could convince me otherwise.

If I had to do it myself, I’d likely purchase a simple soil pH chemical test kit from a company like LaMotte. These kits are sufficiently accurate to make management decisions.

LINK

If you only have few samples it’s best to pay the AgCenter $10 per sample to have the soil analyzed. At least you know your results will be accurate and you will (should) be provided recommendations with the test results on how to amend the soil for the plant(s) you are growing - if any amendments are required.

Just the pot

It appears you are using an appropriate potting mix for your container citrus b/c I can see the perlite granules in the photo. I would suspect your soil pH is more than likely satisfactory. Potting mix is fine for growing citrus. Don’t try to overthink the pH.

There is a Horticultural professional in SC called the “Citrus Guy” who grows 50+ varieties of citrus in containers. Written a short easy to read book on the subject - you can buy it on Amazon if you are interested. Has a chapter on fertilization of container citrus.

The Citrus Guy

He uses CitrusTone organic fertilizer (follow label on the bag) supplemented with liquid fertilizer (think Miracle Gro) at 2 week intervals (follow the label instruction).

The 19-5-10 you are using is likely more than adequate for in ground citrus - but likely is a slow release formulation. Consider supplementing your citrus container every couple weeks with a liquid Miracle-Gro type fertilizer. I think all these have micronutrients like iron and magnesium, but you can check the label. I suspect doing that take care of your issue - but give it time to work, at least a month or so.

Some great info, thanks abunch. Just ordered that book as well. I have only had these for a year now (1 meyer lemon, 1 key lime). Both have tripled in size since I bought and potted them, but this is the first that they are bearing fruit (had some flowers blossom last year but didn’t amount to anything). Trying to do my due diligence to make this a good first harvest, preciate all the imput.

Monroe, but I have em in half whiskey barrels on wheels. If it gets too cold I can wheel em in the carport.

Glad to share what info and limited knowledge I could as I'm pretty much in the same boat as you. I also planted 2 Improved Lemons and 1 Key Lime in containers last February. One of the lemons probably produced 30 or 40 this past winter, and the other about a dozen. I had remove 2/3 of the crop while green on the more productive tree, because tree could not support the weight of the lemons and started breaking a few of the branches. So be prepared to support your limbs on the lemon later this fall/winter or remove some before they turn yellow if you need to. And by the way, the green lemons were large enough to juice, so we did so and froze the juice in ice trays.

If your trees have tripled in size since you have planted them you are clearly doing it right. Currently I'm following the Citrus Guys fertilization scheme, using the Citrus Tone (smells horrible) every 6 weeks + liquid fertilizer twice a month. I'm using Jacks Classic Citrus Fed 20-10-20 (water soluble with micronutrients) as the liquid fertilizer - ordered off of Amazon. 1 small (1.5 lb) container should last you a year if you are interested in trying it. Not saying its any better than Miracle Gro or Vigro at Home Depot, but it is supposedly formulated for container citrus, so why not. When I use the Citrus Tone up, I'll likely switch to slow release granular fertilizer formulated for use on citrus (as you are doing) and maintain the use of liquid fertilizer.

Lastly, as stated by another poster, citrus can outgrow their containers, so the recommendation is to remove the plant from the container after about 3 years if it is root bound, prune the roots by removing 25% to 1/3 of the outer roots and bottom ("root pruning"), and put it back into the container filling the voids with new potting soil. Common practice with most long lived container shrubs/trees. I think the Citrus Guy covers that in his book, but other sources on-line describe the process as well.