A while ago , I visited a Hampshire nursery which raises more than four million orchids a year . It was like a slow-motion factory ; tissue-cultured plantlets came in at one end , flowering specimens trundled out of the other , each in a posh ceramic pot . Orchids , particularly Phalaenopsis ( moth orchids ) , have become Britain 's favourite houseplant but most die within weeks . That should not happen . Moth orchids are easier to nurture than indoor cyclamen or poinsettias and , with care , they can flourish for years . But it helps to know a little about this weird plant group and to understand its special needs . Hardy beauty : Moth orchids ( pictured ) need gentle treatment to produce glorious blossoms . More than 22,000 species of orchids make up Orchidaceae , the world 's largest flowering plant family . About 50 are native to Britain , and the common spotted orchid grows in my own tiny flower meadow . With such a huge range of habitats , orchids ' needs differ widely . But once you learn the likes and dislikes of popular houseplant orchids , it 's not hard to keep them happy . KNOW THEIR NEEDS . Phalaenopsis , like many cultivated orchids are epiphytes , meaning that they grow in bark crevices in forest trees . They subsist on rain or mist , and nourishment comes from debris lodging in the tree bark , so their sparse roots are as important for clinging on as for absorbing nutrients . In a pot in your house , the orchid needs to think it is in a tropical forest . That means a minimum 16 degrees Celsius ambience , humidity and good light . To boost humidity in spring and summer spray rainwater on to the leaves from an atomiser ( if possible always use rainwater warmed to room temperature ) . In winter , move your orchid closer to an east or west-facing window and the extra light will encourage flowering . The commonest cause of death is overwatering . To avoid that , imagine the orchid perched up a tree , soaked by rain from time to time but drying out in between . Cram the roots into wet compost and it will die . That is why it is best to grow epiphytes in slatted containers or transparent , perforated orchid pots and to allow the prehensile roots to poke into the air . During the growing season , feed monthly with special orchid feed . But in winter , reduce watering and do not feed . HANDS-ON MANAGEMENT . Phalaenopsis should last for about three months but , when they fade , you can persuade the old stem to sprout again . Feel it carefully for swellings ( nodes ) near the base . They are dormant buds . If you cut the stem just above the second node from the base , a new flower spike should develop . Repot your orchid only if it has become pot-bound or has been in the same compost for more than two years . Do that when the pale roots develop green tips ; a sign the plant is ready to repot . Use special epiphytic orchid compost — it will appear coarse and lumpy and is available at good garden centres . Remove any dead or shrivelled roots , shorten the remaining healthy ones to about 12cm and replant the orchid in the same size pot . Pack the compost in firmly for stability and allow any upward-facing roots to grow out over the container 's sides . Water thoroughly , making sure all the compost is moist and that the water drains away easily . Next year , when the repotting has worked and you are flush with success , start looking for different orchids . The number of new varieties introduced each year beggars belief . Happy hunting .
Orchids have become Britain 's favourite house plant but die within weeks . Moth orchids are easier to nurture and can flourish for years . With more than 22,000 species , orchids ' needs differ widely .