Growing citrus in plastic pot in patio on East side
I only have a tiny patio with a 2x3 feet garden where underneath it is tree roots from 20 years ago when the land was oak and pine tree farm. Those roots are still turning up clay soil. Most of my plants are in containers. I bought 20-24 gal plastic pots for my citrus plants a few months ago because the citrus have been in grower's pots for too many years. 1 or 2 of the citrus didn't have much roots, so I put them in a guesswork mix of compost + handful of Miracle Grow potting soil + gravels, and line 2" of the pot bottom with gravels and pebbles. I have 2 Kumquats (new this April), 1 grapefruit, 1 Meyer lemon, 1 mandarin, and 1 Satsuma. Since my potted plants are on concrete in a patio that has sunlight all day, I need my plants to be in moist growing medium so they won't die like my beautiful ficus did many years ago. The TX heat actually dried up the roots of my ficus.
Right now my Kumquats are having patchy yellow leaves. One of them has yellow patches with brown squiggly lines inside some of those yellow patches, or pale spots inside yellow. The other one has yellow leaves too, but more leaves turned yellow in a different way after I sprinkled Peters 20-20-20 on the mulch that is above the mixture of soil/compost/gravels. I did that because my plants are very weak looking and I guess the rain water that we've been having has washed away all nutrients in the soil mix. The application of fertilizer helped turn the leaves on my Meyer lemon green from yellowish light green. However, my Kumquats looked even worst. They had red mites on them before, but don't see them any more. May be the swamps of ants ate them? How can I bring my Kumquats back to health? What is wrong with them? Should I add sand to my soil mix? The 2 plants that have new leaves are on plant trollies, so I'm guessing it could be the heat. That heat we're having almost dried up my tomato plant in 1 day. Thanks for any input.