I'm not sure it's going to be possible to keep this healthy inside. These trees grow in the sun all day, not an understory plant. Is the window usually uncovered when it's daylight?

I agree w/what Tiffany said.

This is a tree that does not like wet feet; and, if you're watering ".... whenever the top of the soil feels like it is drying out slightly", you're definitely over-watering. Try watering when the soil is almost dry at the bottom of the pot. You can accurately determine what the soil moisture level is like at the bottom of the pot by using a tell.

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 for your comment Al, would overwatering cause the leaves to go crispy and fall off though? I thought it would do the opposite and make them go soft and soggy before falling off as with most plants? I've only had this plant for about 2 months and probably only watered it about 4 times so I'm assuming the soil is the issue

With what you said immediately above, it sounds like there is a possibility you might be under-watering; however, if what you said about 'not watering until the top of the grow medium is just starting to go dry, it can't possibly be under-watering. The reason lies in the fact that when the top of the medium turns to a lighter shade as the soil dries down slightly, there is still more than enough water in the medium to satisfy the plant's need for moisture. In fact, when the top inch or two of the medium becomes dry, there can still be several inches of the medium which is 100% saturated with perched (excess) water at the pot's bottom. Refer to line drawing A below. The pot is 13" deep, and filled with a grow medium that supports 4" of perched water at the bottom of the pot, which the shaded area represents. If this pot is watered when the top inch or two of the grow medium first feels dry to the touch, all or almost all of the perched water is still in the grow medium and the roots are chronically starved for oxygen. That's why monitoring moisture levels deep in the pot is so much more important than monitoring moisture at or in the top inch or two of the grow media's surface where the roots serve little function other than as a conduit through water and nutrients move. IOW, there are usually very few of the almost microscopically thin roots near the top of the grow medium, and those are the roots that do almost all the plant's heavy lifting.

"..... would overwatering cause the leaves to go crispy and fall off though? I thought it would do the opposite and make them go soft and soggy before falling off as with most plants?" Yes. It might seem strange to hear over-watering causes the same drought response as under-watering. It's very common for plants over-watered to die of thirst in a sea of plenty; this, because in order to function normally and remain healthy, roots need an oxygen supply as much as they need a water supply. Lack of oxygen limits the roots ability to move water to the plant's most distal parts, which would be root tips and margins. If it can't keep these parts hydrated, the problem is first made manifest in crispy leaf tips and/or margins, depending on leaf shape and other factors. Even plants genetically programmed to deal with severe drought will present spoiled foliage, or shed foliage as a survival mechanism. Because the symptoms are generally the same for both under/ over-watering, we/ need to dig deeper to figure out which of the maladies might be at fault. Also, compacted grow medium with or without accompanying under/ over-watering can cause the same leaf symptoms due to the fact that compacted media limits the amount of oxygen the medium can hold.

Al

While watering may be an issue your main problem will be lack of light. This is unlikely to make a successful longterm houseplant, I’m afraid. The best broad leaved house plants are species which naturally grow in a shady tropical understory, not in wide open, sun drenched grasslands.

not much like to be constantly wet ...

lift the inner pot out.. is there accumulated water in the non draining pot ... or is it stained.. indicating such water ....

what al said... water a plant when it needs water ...

ken