Zoomed-out picture of the trees.

A view up one of the branches of new growth. Yellowing decreases as you go upwards towards the end of the branch.

What is your fertilizer regimen, and do you flush the mix periodically?

To my eye, it looks like possible fertilizer burn.....but I'd need to know more about your cultural habits.

Josh

The problem with adding a lot of vinegar to such basic water is that the vinegar neutralizes the basic elements and the result is salt. The symptoms I see could all be caused by salt. A better approach would be to add the vinegar to the water and let it stand for a day or more; perhaps the salts will settle to the bottom. Aside from that if you are using an essentially neutral mix, there is no need to lower the pH of the water below 6.5.

Thanks for the quick responses.

I have flushed the mix once. How often should I be doing that, more than a couple of times per year? I suppose I could try doing so again...

I typically mix 1-1.5 teaspoons of Foliage Pro into two gallons of water and pour about half into each container. Much of it (~1/2 gallon in each container) completely drains through, and I pump it out of the saucer for disposal using a small hand pump.

I recommend that you do a thorough flushing about once a month....or every three waterings or so.

Another thing - do you moisten the mix before fertigating? I think it's very important to make sure that the Gritty Mix is completely moist (no dry pockets) when fertilizing.

So you're fertilizing at 1/2 strength....but I still don't know how often you fertilize.

Josh

I am tending to think what Josh is saying..

You are using the right ferilizer and vinegar can do no harm at one tablespoon per gallon....

Hello Josh) Great to see they let you out of lock down..Sheesh..

MIke

(Hey, Mike, thanks! Was stuck with the students until 6:45pm on Friday. All safe, though).

I'm fertilizing every time I water them. My logic is that the foliage pro directions say 1 tsp per gallon per week, and I'm watering approximately twice per week with 1 tsp per two gallons. Should I back off?

I'll try flushing again. How much water do you recommend running through on a flush?

Hey, Kwebb

Patty told me once fall starts to lower the dose of foliage pro to half a teaspoon since citrus start to slow down their growth.

Kwebb,
1/2 strength twice a week is correct. You might try fertilizing full strength once a week to see how the tree reacts.

To flush, if I'm remembering rightly, you pass about seven times the volume of the container through the medium. To get the most out of the flush, do a pre-watering to saturate the mix, then do the formal flush about 20 minutes later.

Josh

Ok, it sounds like I should try the following:

-Flush the mix to remove any salt buildup, wetting it first.
-Cut back a bit on the amount of fertilizer during the colder months.
-Fertilize less often but in larger doses.
-Wet the mix prior to adding fertilizer.

I'll give this plan a try and report back on the results.

Thank you all for your help, and hopefully I'll have good news to report!