Gardening: Top of the pots

Not so long ago, tropical orchids were beyond the scope and capability of ordinary gardeners.

How different things are today – orchids have become Britain’s most popular house plant, and Christmas is the time for giving – and getting – them. You can buy fancy varieties at many stores and outlets, while the internet has made it simple for a would-be orchid grower to get just what they want.

Of all the orchids, the moth orchid – Phalaenopsis – is the most popular. Unlike some orchids, which can look almost sinister, Phalaenopsis is spectacularly beautiful. Its arching sprays of rounded, white or pink blossoms, often with yellow or greenish suffusions, are amazingly long-lasting, too.

Sadly, though, most Phalaenopsis are condemned to short, unhappy lives – but given the right treatment they can grow and bloom for years.

Phalaenopsis enjoys similar conditions to humans. Give it a warm, draught-free room, plenty of diffused daylight, occasional feeds and regular drinks, and it will be happy as Larry. Also, when the current flowers die, sever the old stem above a dormant lower bud, and a new flower spike will grow.

In its native habitat, Phalaenopsis grows in the forks of trees or in rock clefts. It won’t grow in soil, but can eke an existence from fragments of bark, moss and debris that gather around its spidery roots. It’s life on the edge.

That’s important to know, because the biggest mistake most people make with orchids is to overwater them. When you give your orchid a drink, let the water run right through the bark chip compost and drain away completely. Never leave a plant standing in water.

The second mistake is to repot an orchid too soon. Don’t repot until it is pushing itself out of the container with its strange, twiggy roots. Even then, wait until it has finished flowering.

You’ll need orchid compost to hand, available from specialists or good garden centres. When you’ve removed the plant from its old pot, shake most of the compost out of the roots. With secateurs, trim over-long roots back, leaving at least 4in of each still attached. Remove shrivelled roots or dead leaves and pop the plant into a larger container.

For the first week or so after potting, moisten the compost surface to stimulate root growth. Water your orchid every 10 to 14 days thereafter and feed it, on every third watering, with a specialised orchid fertiliser.