I don't know whether gardenias have any special needs, but I can ask some questions and provide some general information until someone smarter than I am pipes in.

First, because I'm an ignorant American, when is it spring in Lahore? That would help us know the best time of year to do real work on your plants.

What are your other gardenias planted in? Do the coco chips in this pot seem to hold some water?

It does look like the chips provide a ton of air and fast drainage, both of which are essential for healthy roots. The only concern I'd have is whether they can hold enough water to keep the roots moist in the dry season. If Singapore's climate is like yours you could probably switch all your plants over. If not, you might be able to compensate by watering more often in the dry season--maybe.

But that's just my uninformed guess. I'll follow this thread to see what others have to say about it.

Spring in Lahore is very short usually consisting of 1 month of February when temps are around 15-25 C. We do all the real work on plants in our mild winters or in spring.

My other gardenias are planted in various mixtures. one is 50% loamy soil, 25% leaf compost, 25% pumice. Another mixture is 100% loamy soil. Another one is 33% peat moss, 33% leaf compost, 33% perlite. All are growing fine specially the last one. But i always use tall clay pots and not plastic pots. Coco chips in this pot do not seem to hold water apparently but because it is plastic non-porous so moistre is maintained for bit longer time.

Our summers are different than thailand in the sense that their humidity level is almost always high in summer whereas we get a around 2 months of continuous dry heat in May/June and then we get the humid monsoon in August.

I am hesitant to grow in 100% coco chunks because of fear of root rot. I would like a mixture which is forgiving in terms of over watering but the growth of this gardenia in just coco chunks is very tempting to me. At the same time, i do not want my gardenias to be watered like twice a day when temps are ranging around 48 C and i garden on rooftop (I do have green shade net on top).