Orchids, like any flowering plant, put out more blossoms when they have been fed regularly. Most orchids are planted in airy but nutritionally deficient mixes. Orchids must get their food from fertilizers, since their mixes provide little to them.
Why Fertilize Your Orchid
Most retail orchids are epiphytes, normally growing in the branches of trees. To mimic this situation, they are potted in very light, airy mixes. These potting mixes don't have much in the way of nutrition, so to help the plant build up enough energy to bloom you must feed it.
When to Fertilize Your Orchid
In the winter, orchids are less active and less needy. Once spring arrives, the orchid starts its growth efforts and needs to be fertilized. Brennan's Orchids website recommends feeding your orchids every other watering, spring through fall, with a balanced plant or orchid-specific food.
Miracle Grow as an Orchid Food
Miracle Grow is a fine product but is not specifically formulated for orchids. You can use it successfully on orchids if you dilute to no more than half the usual strength. Orchid roots burn easily and this protects them from damage.