Answer: I know how disappointing it is when newly acquired plants fail to thrive. When leaves drop suddenly, it indicates the growing environment isn't quite right. Tropical plants appreciate bright light and warm temperatures. They don't like drafts (from air conditioning or heater vents, or from opening and closing front or back doors). It's possible that your plants were stressed when you took them home - even a brief exposure to wintertime temperatures as you moved them from the store to your vehicle and into your home could cause them to drop their leaves.
At this point, I'd recommend keeping them in a place protected from drafts; give them bright light but not direct sunlight; water them thoroughly when the top of the soil looks dry and the pots are lightweight when you pick them up. It's important to water them before they begin to wilt but also to allow the soil to dry slightly between waterings. If the soil remains saturated with water, the roots can suffocate.
Hope these suggestions will help you help your plants regain their health.
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