Typically Phals. initiate spikes after a couple weeks or so of being exposed to lower night temperatures. Drops into the 50s at night should be enough to trigger the spike initiation. Sometimes, the plants will spike and the buds will "blast" or form keikis instead of flowers. Blasting usually occurs when conditions change drastically while buds are forming (major drops in humidity or temperatures is usually the main culprit). Keiki or plantlet formation doesn't usually occur in Phalaenopsis in a manner that replaces buds for plants, but it is common in Dendrobium nobile and its hybrids. Often, it is the result of not giving the plants a sufficient winter night temperature drop or because of too much water in winter. Phals. often produce keikis at the non-blooming nodes of spikes after the initial flush of blooms.
Originally Posted by Cremmy18