Help! Outdoor plant leaves curled upward and appear dry

Hello All,

2nd time grower here. Started a few plants in mid April in the same place as last year after preparing the soil with lyme and new topsoil. They are now 5 to 6 feet tall and still growing steadily. Similar to last year, I used Miracle Gro mixed half strength poured only at the base of the plant every 2 - 3 weeks. Everything was going well until about a month ago when I noticed some of the leaves starting to curl upwards on one plant and they appear very dry and brittle(As pictured). The other plants appear to be fine, but one is starting to have the same issues just on a couple fan leaves. I haven't checked the ph of the soil, but Im fearing I made it too acidic and Im experiencing nutrient lock-out. Some of the stems on the other plants are turning reddish which also makes me suspect of this. I applied a few tablespoons of Epsom salt to all the plants leaves last week and it doesnt appear to be getting better. Any suggestions on remedies to reverse the ph or deficiency would be much appreciated. Thanks for your help in advance!

I'm just guessing here and I really am a no nothing so feel free to ignore me. If you just want to raise the Ph why dont you just go buy some PH up and water your plants with some water with a High PH ?

I have fed my plants full strength MG and the low ph 30-10-10(MG azelia food) with feedings 2 days apart when I ran out of Maxigrow. and I really really really overfeed everything and havent had a problem.

How often do you water? How much of the orange do they get a day?

Hey, thats probably good advice with the PH up, although im trying to reduce the amount of chemicals so maybe I will try out some more lyme first.

As for Sun, maybe 5 hour direct and 3 indirect. I water probably every week, but it's been raining naturally quite a bit.