@meyermike Since I was not sure about the mite damage, I went to buy the pesticide for it and used it, but nothing has improved so far. It's been several weeks... @Tapla Yes, I usually measure the pH using the pH indicator from my lab. I always make sure it's around 5. I use the same fertilizer as the one I use for my Hydrangea. @meyermike Hah! So it might not be about the mites outside but inside the soil??? I didn't know there is no such thing? My gardenia's soil has never had the chance to hold water for too long though, because of the big hole underneath the pot everything went out. It took less than a week for the soil to be dry again. Now spring has arrived it is growing so many new leaves and flowers all over the place it becomes very hard for me to check everything. If I want to change the soil I should change it now right? Will it solve anything? If there are mites leaving on the roots, changing soil won't remove them right? I just notice something but the leaves of my gardenia never falls, like never ever. The oldest leaves look the worse. With all those yellow spot as shown in the picture. Please help. :

Hi Jessica! No, salts are not an issue unless of course you gave your plants sips for weeks and over fertilized.. In fact I was going to tell you to check for pest Jessica. In particular spider mites. I have the feeling your plant is still adjusting to the mix along with environmental or cultural changes. It may and not taking up nutrients for some resason. Some of the very top pictured leaves also look as if something was sucking the moisture out of the leaves which is why they look puckered a bit. Is the plant outside now? What temps are you getting? Also, there is no need to water with vinegar right away, not that is will cause any harm, but the mix you started out with started out at a good acidic level. It will take a while before you notice issues with any mix, unless of course your water is very alkaline. Have you had your water tested or called the local municipal water provider to find out what it is at? Mine is at 8.5 I remember that happening to my leaves while I had spider mites, when I forgot to add gypsum to my mix before using FP, when the nights were too cold, when I introduced my plants too quickly to sun outdoors, and when the temp swings were to drastic, which can cause nutrient delivery problems which in tune can cause an Iron, Mg, or Nitrogen problem Were the leaves sort of looking like that before you transplanted? Eventually, it corrected itself. Yes, posting at the container forums will give you many more ideas too. This may be a matter of a process of illumination. I would start with concentrating on keeping your plant anywhere where it gets lots of sunlight and consistent temps, along with a check over for pest and feed well. All should fall together perfectly and you should see a stark improvement. Do not even think about worrying about the mix, since I can assure you it is just perfect. Mike:-)))))

Sounds like you're in good shape. I on the other hand, after seeing the title of this thread have an old Tony Orlando and Dawn song going through my head...

The second from the top photo seems to show the typical lacebug excrement. The top photo, however, seems to show more than just lacebug damage. It's not clear in the photo, but the stems show what looks like either aphids or scale. Mites are too tiny to show up well, but there don't seem to be any webs (which are not produced by all mites) present, at least that I can see. At this point in the year treatment for lacebug, except raking up and disposing of fallen leaves, is not necessary. The same would be true for aphids. Scale is another story. You really need to have a branch or two examined by your county extension service or state agriculture department. They can also recommend best treatments for now, if needed, and next spring to prevent infestation next year. The bottom photos all show the normal yellow discoloration that rhododendron leaves acquire just before they are naturally shed. The spots are produced by fungal infections, but identifying which of the dozens of types is not really possible without laboratory analysis and is not necessary. Rake up the fallen leaves as above. This can help, but most rhododendron growers just ignore the spotting on leaves that are about to fall anyway.