Cymbidiums need dividing when they overcrowd their containers or get too heavy to carry.

• Water plants well before dividing them.
• Use a can cutter or sharp knife to cut off the plastic container. If the plants are in a wooden tub, remove the old container with a hammer, and discard it.
• Use a large kitchen knife kept for gardening to cut between the pseudobulbs (the bulblike structures growing above ground) and down through the roots. Aim for at least three productive pseudobulbs and four or five back bulbs per division. (Back bulbs are fully grown pseudobulbs that once bore leaves and flower spikes but now are bare. They act as storage containers for the remainder of the plant.)
• Trim off all roots that are diseased, damaged, or simply messy. In all, you should remove about one-third of the roots.
• Optionally, soak the divisions in a solution of 1 quart bleach to 10 quarts water for ten minutes to kill any fungus or rot. Air dry them.
• To replant, choose plastic containers that have plenty of holes in the bottom and are the next size larger, or approximately 4 to 6 inches wider than the top of the root ball. (Oversized containers slow growth.)
• Hold the plant so that the bottom of the pseudobulbs is level with the top of the container. Fill around the roots all the way to the top of the container with a commercial soil mix recommended for cymbidiums or with a homemade mix, such as 2 gallons pathway bark, 2 gallons ground nitrolized wood shavings, and 1 gallon commercial sterilized potting soil. It's important to make sure the roots are completely covered with soil mix but the pseudobulbs are totally above ground. (If the pseudobulbs are buried, they'll rot.)
• Water the cymbidiums thoroughly after planting, keep them in semishade, and wait two or three weeks before starting to fertilize