To answer the original question it seems as tho the plants are just super stressed, and when they get stressed they drop their leaves and fruit to survive. They are getting much different conditions than they were at HD, where they outside or inside a greenhouse in HD? I am going to guess that they were inside or at least shaded, they had to be hardened off in before just putting them in full sun. This is done by SLOWLY introducing them to the sun for a short period of time gradually working up to full day sunlight. Stop fertilizing and watering until you know for sure they are dried out. Than completely soak and repeat the cycle. Citrus will survive slightly dehydrated better than they will flooded. The meter you are using measures the electric conductivity of the soil so if it is littered with fertilizers you will get false readings. Are you able to post pics of the trees and their pots? I would suggest a re-potting and pruning, but as you said you are new to gardening and this may scare you a bit. Do you have any friends with a green thumb that could help you with this? Don't expect any flowers or fruits till next year as said since the plants are so stressed, but you never know with some TLC and luck you may get some winter blooms. Again pics would really help, and good luck!

Oh boy. MORE WATER. Soak that tree. What kind of soil is the tree planted in? Do you know how quickly draining your soil is? Is it mostly sand, clay, calciche? I would make sure you fill that well at least 3 times. Make sure your soil is moist at least 24" down. Spray your leaves to help cool off and be sure to give your little tree some shade over the next couple of weeks. Planting in the dead heat of an AZ summer is probably not the best time to put any plant in the ground, even a citrus tree. I often will avoid putting trees in the ground out here in S. California at this time, and I'm only 6 miles from the ocean. This is just a very dry, shocked little tree. That being said, citrus are very resilient. Just keep this tree hydrated and cool. You may lose leaves, don't worry. As the tree recovers, you'll see new flush. Don't fertilize until you see definite signs of recovery. Patty S.

Hi Monica. I was looking at your pics when I zoom the pic kind of blurs out . It looks like a branch has some damage either by an animal that took some bites out of it or it was scraped on something not to worry it should heal . I do see white specs around the wound might be cottony cushion scale . Also check for spider mites very common on indoor citrus you will need a magnifying glass . I would leave space between your trees just incase you do have bugs on your lime tree .When watering I gently tip the pot if it moves easily it needs water . Does the tray underneath your pot collect water ? Make sure no water collects in the tray . Next time you water take your tree outside and give it a good shower this will remove any dust and spider mites . Also I would place a small fan near your trees they love good air circulation . Good luck Brian

Thanks dev but I think the pic is deceiving, the pot is no wider than my regular 5 gallons, it is just a 2.5 gallon. I know the whole citrus taproot thing isn't true but I would imagine that as the trees get big the roots will almost fill the pot. No? The tall pots still make sense for me for space conservation in my grow room. I noticed the same thing Laura as repotted but I assumed that was because the old mix was boggy so the roots didn't want to go down. I thought with the 511 they may be more inclined to spread out a bit.