Hi Becky,

When orchid buds turn yellow and fall off it is called “bud blast.”
Here are some of the reasons “bud blast” may occur.

Environmental conditions: Orchids are sensitive and may drop buds if there are fumes from paint, rug cleaners, and other chemicals in the air. Also fumes from natural gas, methane, or ethylene can cause problems.

If the soil gets too dry, the orchid takes moisture from the buds causing them to dry up and fall off.

It the plant gets too hot (in the direct sun or near a heater) or too cold (near a cold door or window, near an air conditioner) buds drop.

Different orchid varieties need varying amounts of light. Lack of sufficient light stops bud development.

If you over water while the buds are developing, the buds turn black and die.

Phaleonopsis orchid and buds