Q What are cymbidiums?

A Cymbidiums are more demanding than many orchids commonly grown as houseplants. They must be placed outside in the summer. They flower from autumn to spring, and produce large flower spikes that can last up to eight weeks each.

Caption: Cymbidiums bloom from autumn to spring

Q Where's the best place to put cymbidiums?

A Cymbidiums need lots of light and low temperatures. Only keep them indoors during autumn and winter. When inside, stand in a bright spot, such as a cool conservatory or windowsill, away from direct sunlight. Keep at about 10-15°C until the flower spike is well developed. You can then move it to a warmer spot, around 20°C. If it's too warm the resulting flowers soon fade. When the risk of frost has passed, harden off, and give it a warm position outside in dappled or partial shade.

Q How should I water and feed them?

A Water your cymbidium once a week all year if needed, using rainwater or filtered tap water. From autumn to spring feed fortnightly, and every week during spring and summer, using a balanced liquid feed at quarter to half strength. To encourage flowering, switch to a tomato fertiliser every week in August and September at quarter to half strength. Cymbidium flower spikes are heavy and need support. Insert a small cane as soon as the spike forms to keep it upright. Position the canes in the middle of the pot to avoid damaging new roots.

Q How should I repot them?

A  These need repotting only when they're root-bound. This is best done from February to May into a pot just larger than the original. Cut off any dead roots and remove as much of the old compost as you can without disturbing the root ball too much. This type of orchid has pseudobulbs, swollen tubers at base of the plant that stores nutrients. Only the young ones flower. When repotting, ensure you give the youngest, greenest bulbs most space. Older, congested plants can be split during March or April.  Tip the plant from its pot, shake off compost and look for natural divisions. Divide into two or three new plants with four or five pseudobulbs each. Remove any dead or damaged growth. Pot new plants into small pots, don’t water them, but mist them daily for a fortnight to help them establish. Then water sparingly for a further six weeks until firmly rooted.