no evergreen .. holds its leaves forever ... but i cant tell from your pix.. if this is the oldest leaves....

how do the fresh new leaves look.. at the growth points ???

why indoors??? ... lights need to be about 2 inches above a plant ... for requisite light levels.. and the problem with a plant as large as yours.. is its shear size.. and how a lamp near the top.. will most likely do nothing for the leaves below .. hence.. it might be shedding them ...

and this is why plants this size.. are usually .. put outside for summer ...

there arent many houseplants.. that have many big flowers .. and that is because of the energy it takes.. to generate many big flowers ... and if your lights are not giving the plant enough light.. then something has to give.. and its usually the oldest leaves ...

you can not make up low light levels.. thru fertilization ...

ken

I'll go out on the limb and say its nutrient burn. Rarely does a plant need nutrient every watering.

I'll go out on the limb and say its nutrient burn. Rarely does a plant need nutrient every watering.

Lavender, gardenias are rather notorious for being diffucult to maintain in containers for very long.

I'd evaluate your potting medium, making sure that it drains freely after a proper watering. The whole volume should be soaked on watering day, then allowed to dry out a fair amount until the next time. If you're fertilizing every time you water you must be certain of the porosity of the mix and that the container is drenched with pure water occasionally.

It's really not necessary nor beneficial to fertilize a plant growing in a peaty medium every time you water.

Misting the plants so frequently is an excellent way to encourage and spread plant disease. And unless your water is free of minerals and additives, it can cause burn where it collects on the leaf tips.