What to do when your orchid won't bloom

Q I've had an orchid for three years. It looks fine, but it has never bloomed. It looks healthy and grows new arms, but I would like it to bloom.

- V.G., Springfield, Ill.

A "It is always difficult to make suggestions about orchid care without knowing exactly what kind you have," says Larry Hodgson, author of "Houseplants for Dummies."

There are thousands of varieties and each type has its own specific needs. But since you mention 'arms,' Mr. Hodgson assumes yours is one of the species with pseudobulbs. It may be a Cattleya or one of its close relatives, all of which need about the same general care.

If your plant looks healthy and produces new pseudobulbs, it is obviously thriving, so you won't need to make much of a change in your growing conditions. Hodgson recommends:

1. Move the plant closer to the light or to a brighter window. Although Cattleyas often appear to thrive under medium light, it is often insufficient for blooming. Full sun is needed for them to flower well. Many indoor gardeners find their Cattleyas bloom best when they get so much light their foliage bleaches out.

2. Increase the atmospheric humidity by running a room humidifier, as flower buds may abort before you even notice them if the air is excessively dry.

3. "Kick-start" the flowering process by giving the plant lower night temperatures. Many Cattleya species undergo an annual period of cool weather in the wild and count on this as a signal to start blooming. Another advantage of cool night temperatures is that most other orchids like things as cool as, or even cooler, than Cattleyas, so if you have another type, they might still encourage it to bloom.

Finally, after three years of use, the medium in which your orchid is growing is probably close to decay, so repot into orchid mix (available at local nurseries) when new growth starts to show, probably in mid- to late winter. Don't use regular potting mix: Orchids need a better- aerated mix than other houseplants. For more information on growing orchids, read "Ortho's All About Orchids."

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