A: Phalaenopsis or moth orchids tend to thrive on what seems neglect: Water every three weeks and fertilization every other month. The "10-10-10" or "12-12-12" refers to a balanced fertilizer with equal amounts of nitrogen, phosphate and potassium, the macro-nutrients that all plants need for growth and development.
In the wild, orchids depend on decomposing leaves for most of their nutrients. They don't need much.
For best results, use a water-soluble fertilizer specifically designed for orchids. According to experts, orchids planted in bark may need a higher amount of nitrogen (the first number in that three-digit formula) because the decaying bark will use up a lot of the available nitrogen, leaving little for the plant. That's why some orchid foods are 30-10-10, for example.
Before feeding, water the plant well and get its bark or other planting medium moist but not soggy. Discard any water and/or fertilizer that accumulates in the pot's saucer or decorative container; standing water can cause the orchid to rot.