Indoor plants can shed leaves for a variety of reasons, usually resulting from environmental stress. Inadequate light or over-/under-watering are common causes, though others can be pests and temperature swings (drafts from windows or heat from vents).

Schefflera prefers relatively bright light (not necessarily hours of direct sun, but a bright window or perhaps even a bit of direct sun, especially in winter). With insufficient light, a plant does not have enough energy reserves to maintain its full complement of foliage, so some (usually the oldest or injured) is shed to conserve resources. Light can also impact foliage retention when a plant is shifted from one light intensity to another. Leaves have limited ability once they are formed to adjust to different light levels, so when it experiences new conditions, plants may have to regrow foliage that is better-adapted to the new intensity and shed leaves which are not.

Soil should be moistened thoroughly when watering is needed but allowed to dry some in between so roots can "breathe." If soil becomes too dry between soakings or remains damp too consistently, roots can suffer damage, and because they aren't functioning properly, the plant cannot remain well-hydrated. As before, the plant then conserves resources and jettisons some foliage to reserve moisture, usually to support its youngest growth. Over-watered roots can also produce a hormone that stimulates leaf drop. If a pot is lacking good drainage, transplanting into a pot with drain holes will help. If a well-drained pot is kept on a saucer, making sure the water saucer collects is emptied right away will prevent over-saturation of the soil.

If the plant has been potted in the same soil for a year or more, it may benefit from repotting with fresh potting mix. Old soil tends to compress over time as it gradually breaks down, which results in longer drying-out times and slowed root growth. Build-up of tap water minerals and/or fertilizer "salts" (assorted minerals, not necessarily sodium) can also accumulate to root-damaging levels in old potting mix. As with the above situations, ailing roots can lead to leaf loss - especially if new leaf growth is not forthcoming.

If neither of these issues seems to be a factor, check the leaf undersides for signs of mites, mealybugs, thrips, scale, or aphids. All are treatable, though treatment options may vary a bit depending on which pest is present. Otherwise, make sure the plant is out-of-the-way of direct drafts from cold windows, HVAC vents, radiators, and fireplaces. Leaf drop can also be triggered by another plant hormone - ethylene gas, which quantities of ripe fruit can produce if they are in close proximity to the plant.

If you have recently purchased this as a new plant or moved the plant to a new spot, it should eventually acclimate to its conditions and cease dropping leaves if conditions are otherwise suitable. If not, you're welcome to send us photos of its overall condition and any notable symptoms so we can assess what might be stressing it.

Miri

Given the relatively slow metabolism of indoor plants in winter (when in natural light, at least), it's possible the move five weeks ago is still resulting in a leaf adjustment by the plant as it acclimates to different light levels or other conditions. Similarly, perhaps the increase in heating needed as the weather has turned colder recently is lowering the ambient humidity further, causing minor stress. Loss of lower leaves (as these are older) is less concerning than if younger growths were dropping. Pruning is not needed now and may stress the plant further, though if the plant resumes good growth later this year and becomes too large, you can lightly trim it at that point.

Otherwise, though the photo is small, from what we can see the plant appears to be in good condition. This spring it would probably benefit from a repotting to one pot size larger, with fresh soil, as it looks a bit large for the pot it's in currently. When this happens, remember to adjust your watering regimen to compensate for the fact that it probably won't dry out at the same rate as before; as always, it's best to just check the soil a couple of inches down before watering.

Miri

Yes, the loss of lower leaves is usually not too alarming and the fact that there is new growth is a good sign. Despite how often it's suggested, misting plants doesn't boost humidity for long, as the moisture quickly disperses to the rest of the volume of air and has negligible impact overall. Some people use humidity trays (which can be as simple as a saucer of water which a plant is raised above via gravel or some other support - the pot base must stay dry) but these too can be inadequate when there's enough air circulation to waft that humid air away from the plant. If a humidity boost is needed, using a room humidifier is usually much more effective. With people, a recommended comfort level is anywhere between 30-50% [Mayo Clinic] or up to 60% [EPA], and this will also greatly benefit any houseplants in the room. Tropical plants usually appreciate even higher levels than this, but such levels are not recommended for home environments due to potential for mold, condensation, etc.; in practicality, they'd also be very difficult to achieve in winter. This does mean, however, that our naturally-high outdoor humidity levels in summer would benefit the plant if you opt to put it outdoors (in the shade) for the summer. Because use of a humidifier entails added expense and the task of its regular cleaning, some opt to have the plants "tough it out" instead until they can summer outside; on the other hand, humidifier use can at least confer benefits to people, furniture, and so forth.

Miri