Caladiums are colorful, ornamental, shade-loving tropical foliage plants that thrive in very warm and humid conditions. Caladiums boast vibrant leaf color combinations in practically endless variations of green-streaked, speckled and variegated whites, creams, pinks and reds. Fast growing and virtually pest free, caladiums can attain heights of 12 to 30 inches in a single growing season. They're very forgiving and perfect plants for either the seasoned veteran or the greenest rookie gardener. Whether potted or planted in a shade garden, care requirements are the same, but only the very warmest climates will facilitate outdoor overwintering.
Select the largest, plumpest caladium tuberous roots possible. The larger the tubers, the larger and more vigorous the plants will be. The roots should have a few buds on them. Plant each root 1 1/2 to 2 inches deep, rounded side up, in its own individual 4-inch to 6-inch pot of well-draining, rich starting soil six weeks before the last predicted frost for your area. The pot should be about 2 inches wider than the length of the root.
Water the planting medium just enough to uniformly moisten it. Seal the pot in a clear plastic bag to retain humidity. Place it in a warm, well-lit location out of direct sunlight. The top of your refrigerator or over the hot water heater are ideal choices. Warmth is very important, because caladiums don't like cold weather and won't sprout if the soil is too cool.
Check the pot each day to make sure that the potting medium doesn't dry out. The appearance of excessive condensation on the inside of the plastic bag can mean that a little water might be needed. Keep the soil uniformly moist but never soggy.
Choose a shady or light-dappled location outdoors for your sprouted caladium after all danger of frost has passed. You can leave it in the pot or transplant it into rich, well-drained soil. If you prefer to keep the caladium indoors, place it anywhere out of direct sunlight. It will thrive even in lower-light indoor conditions.
Water caladiums just enough to keep them moist but never soggy or wet. Fertilize indoor potted caladiums every two weeks with liquid houseplant food. Outdoor specimens can be fed a good all-purpose, water-soluble fertilizer monthly. Prune out damaged or dead leaves, as necessary.
Dig caladiums up for wintering when the foliage begins to look tired and the leaves turn yellow and start falling over in September to mid-October. Leave the remaining foliage attached to the root tubers, and shake off most of the soil. Spread them out in a dark, dry location such as the garage or a storage room to allow the foliage to finish drying out.
Break the leaves from the tubers when they turn tan and become papery. They will separate easily and leave a clean, healed scar. Discard any roots that have soft spots or appear to be rotting. Use a permanent marker to note directly on the tuber which side is "up," or where the foliage had grown. It's sometimes hard to tell top from bottom when replanting in the spring. It isn't necessary to wash the tubers for storage.
Place the root tubers in a mesh or paper bag, cardboard box or nylon stocking. Materials such as these will allow the tubers to breathe and prevent them from rotting. Store in a dark, warm location that is around 70 degrees, for replanting the following spring.