Tried giving it plant food, iron, banana water, but not sure if it's helping.

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thats a lot of remedies ... when did you do all that .. and how fast do you expect results???

how do you water ..

how about a pic of the whole plant .. how long have you had it ...

where is it in the house ... how close to a window ... is it getting sufficient light???

can we rule out a cold event???.. before or since you got it ...

you really havent given us many facts other than leaf damage for us to think and talk about ...

ken

ps: never heard of banana water .. go figure...

double a plant size in weeks.. why am i not believing this:

https://duckduckgo.com/?t=ffcm&q=banana+water&ia=web

you didnt spray this concoction on the leaves did you???

I didn't use everything at the same time and no I didn't spray it on the leaves. Had the plant since November, a couple of months ago it slowly started showing the discoloration. It's less than 2metres away from the window. It's quite warm here, so shouldnt be getting cold. NW windows. Some grow lights from time to time when it's darker days.

Also I didn't say I used an article that suggests it would double the plant size in weeks

The witness marks on the inside of your cache container suggest water is allowed to collect in the cache pot where it evaporates, leaving the dissolved solids behind in the form of the brown matter collecting on and staining the inside of the pot. If this is true, you have your answer. The plant appears to have been chronically over-watered and or is in a grow medium that is not at all compatible with your watering habits.

Al

Thank you! Will find a different pot for it! Usually water it every 1 and a half weeks

Plants, especially those grown in water-retentive media, should be watered on an 'as needed' basis. You might try using a wooden dowel as a 'tell', to 'tell' you when it's time to water. If your pot is 4-5" deep, the advice to water when the top 2" of the grow medium are dry is ok. If you're using a commercially made medium based on peat, coir, compost, composted forest products, ..... and your pot is deeper than about 5", watering when the top 2" feels dry is going to be a recipe for over-watering. Established plantings of Ficus should be watered when you can still barely detect moisture on the end of the tell after it's been inserted all the way to the bottom of the pot.

Using a 'tell'

Over-watering saps vitality and is one of the most common plant assassins, so learning to avoid it is worth the small effort. Plants make and store their own energy source – photosynthate - (sugar/glucose). Functioning roots need energy to drive their metabolic processes, and in order to get it, they use oxygen to burn (oxidize) their food. From this, we can see that terrestrial plants need plenty of air (oxygen) in the soil to drive root function. Many off-the-shelf soils hold too much water and not enough air to support the kind of root health most growers would like to see; and, a healthy root system is a prerequisite to a healthy plant.

Watering in small sips leads to avoid over-watering leads to a residual build-up of dissolved solids (salts) in the soil from tapwater and fertilizer solutions, which limits a plant's ability to absorb water – so watering in sips simply moves us to the other horn of a dilemma. It creates another problem that requires resolution. Better, would be to simply adopt a soil that drains well enough to allow watering to beyond the saturation point, so we're flushing the soil of accumulating dissolved solids whenever we water; this, w/o the plant being forced to pay a tax in the form of reduced vitality, due to prolong periods of soil saturation. Sometimes, though, that's not a course we can immediately steer, which makes controlling how often we water a very important factor.

In many cases, we can judge whether or not a planting needs watering by hefting the pot. This is especially true if the pot is made from light material, like plastic, but doesn't work (as) well when the pot is made from heavier material, like clay, or when the size/weight of the pot precludes grabbing it with one hand to judge its weight and gauge the need for water.

Fingers stuck an inch or two into the soil work ok for shallow pots, but not for deep pots. Deep pots might have 3 or more inches of soil that feels totally dry, while the lower several inches of the soil is 100% saturated. Obviously, the lack of oxygen in the root zone situation can wreak havoc with root health and cause the loss of a very notable measure of your plant's potential. Inexpensive watering meters don't even measure moisture levels, they measure electrical conductivity. Clean the tip and insert it into a cup of distilled water and witness the fact it reads 'DRY'.

One of the most reliable methods of checking a planting's need for water is using a 'tell'. You can use a bamboo skewer in a pinch, but a wooden dowel rod of about 5/16” (75-85mm) would work better. They usually come 48” (120cm) long and can usually be cut in half and serve as a pair. Sharpen all 4 ends in a pencil sharpener and slightly blunt the tip so it's about the diameter of the head on a straight pin. Push the wooden tell deep into the soil. Don't worry, it won't harm the root system. If the plant is quite root-bound, you might need to try several places until you find one where you can push it all the way to the pot's bottom. Leave it a few seconds, then withdraw it and inspect the tip for moisture. For most plantings, withhold water until the tell comes out dry or nearly so. If you see signs of wilting, adjust the interval between waterings so drought stress isn't a recurring issue.

Al

Thank you so much for the information! Hopefully my ficus will do better soon!

..... hoping you have the best luck!

Al