If those were my plants, I would do two things right away, 1-check for bugs. 2-do a soil slurry test.
If there are no bugs, the slurry will give you an insight into what is happening in the root zone.
Your soil looks dry, so it is a perfect time to grab a shot glass or two from the top 2 or 3 inches of your soil, just dig it in there and get a shot glass full, or two. then add an equal amount of water that is 7.0ph, and hopefully does not have high ppms.
mix that up with a spoon and test the ph and ppms after 1 minute, after 15 minutes, and again at 30 minutes. sometimes it changes over time sometimes not so much for me, but it doesnt hurt to grab multiple readings.
try that, and post your slurry results, could be a fun and productive exercise.
peace