There are six main techniques currently used to propagate orchids. Two or the techniques work with most varieties and are the simplest methods for new orchid growers: and these are:
Division: One of the simplest methods of producing more plants of the same variety or species. Although you may worry about damaging your orchid by splitting it, dividing a plant most often encourages it to produce new vigorous shoots with better quality than if left on its own.
Back Bulb: Back bulbs are previously flowered or unflowered back pseudobulbs. Propagation by back bulb alone may take up to three years to grow an orchid of flowering size. Many orchid growers look for back bulbs when they divide their plants.
In addition, orchids are propagated by keikis (produced by Phalaenopsis orchids), which grow on a node along the flower spike where normally a new branch would develop. Aerial cuttings are commonly used to propagate Dendrobiums. Meristem tissue culture needs to be performed under sterile conditions and is most often used by commercial growers who have access to a laboratory. Growing orchids from seed is also better suited to a laboratory, since orchid seed is about the size of dust. While other seeds contain nutrients to sustain a seedling, orchid seed has none and needs special techniques to achieve successful germination and growth.
Most orchids require repotting every 12 to 18 months. Your plant will let you know when it's grown too big for its container with signals like an over-abundance of aerial roots and leaves and new growth that grows at odd angles.
To repot your orchid, first remove old flower spikes and any dead or withered leaves. While dead leaves break away from the plant and are easily removed, you'll need to tear dying leaves down their central vein. Carefully make a small tear at the leaf tip and pull it apart to the stem.