To increase humidity, you can use a plastic bag and skewer. The skewer is used to hold the bag up without touching the leaves. If the plastic touches the leaves, it could cause damage to the plant. The plant was being propagated in water and moved into soil. To help the transition into soil, I placed the plant under a plastic bag for up to 2 weeks to increase humidity.
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Most houseplants prefer humidity levels of 40 to 50 percent. Unfortunately, the air inside our centrally heated homes usually falls somewhere near the 10 to 30 percent range during the winter. To houseplants (especially flowering houseplants), this can feel like living in the Sahara Desert.
Place two same sized containers together with plant inside to increase humidity for tropical plants. This is a thrifty method instead of buying a humidifier.