How to plant, grow and prune an orchid

What you need to know about an orchid

Name: orchid: Cymbidium, Paphiopedilum, Dendrobium, Cattleya, Epidendrum, etc.

Height: up to 50cm according to type.

Foliage: various, depending on orchid type; from strappy to fleshy.

Climate: temperate to tropical; indoor or glasshouse plants in cold areas.

Soil: orchid mix preferred; free draining.

Position: full sun to light shade; avoid direct sun through glass indoors.

Flowering: from single blooms per spike to long, multi-flowered stems depending on type; from white to deep crimson and brown.

Feeding: use a long-term controlled-release fertiliser; supplement with liquid food from spring to autumn.

Watering: keep moist but never wet; do not stand pots in saucers of water.

Appearance and characteristics of an orchid

Most temperate-zone orchids such as cymbidiums are terrestrial – that is, they grow with their roots in a pot or the ground. They're easy to grow without needing a glasshouse or specialised knowledge, and are happy outside in most parts of Australia.

In northern Australia, tropical and epiphytic orchids will also grow outdoors, but in the southern states they are “hot house” plants needing a lot of attention. Learn more about the different types of orchids.

How to plant and grow an orchid

A cool-climate orchid will grow well outside under the shade of a spreading tree or in a shade house, where it is protected from hot sun over summer. In winter, pots can be moved to a sunnier spot, but be sure to shelter them from cold winds. Your orchid will need good ambient light all year – it will not flower if it is grown in dense shade.

Follow these steps when planting your orchid:

1. Choose a pot with good drainage. A “snug” fit is best – the pot should just comfortably hold the roots. Don't put your plant into a large pot so it will have room to expand – it will “sulk”, and deprive you of flowers!
2. Cymbidiums and other terrestrials grow well in a premium-quality orchid mix made from fine to medium pine bark chips (5–8mm), coarse washed river sand or perlite and coir fibre. The mix needs to hold the roots securely and retain enough water to keep the roots moist while allowing excess to drain freely.
3. Make sure the bulb sits on top of the mix with just the roots covered, otherwise it may rot.

How to report and divide orchids

When an orchid has outgrown its existing pot, it can be re-potted in mid-spring after it has finished flowering:

1. Remove it from its existing container.
2. Divide it up by separating the bulbs (these are properly called pseudo bulbs, because they are not a true bulb like an onion, for example).
3. Remove old bulbs that have previously flowered and lost their leaves – they will not flower again, but they may produce a new shoot from the base if you pot them up.

Pot each of the younger bulbs individually  into small pots.

Caring for an orchid

Watering 

An orchid has fleshy roots that rot if they are too wet, so water your plant carefully. It's vitally important that excess water drains freely out of the base of the pot. During the warmer months, water your plant as often as necessary to ensure it never dries out. This could be once or twice a day during extremely hot or windy weather. Try to keep the air around the plant humid by misting or placing a bowl of water close to the plant. Whatever you do, don't stand the pot in a saucer of water!

During cooler weather, reduce watering to once every 7–10 days, depending on the type of orchid and where it's positioned.

Avoid wetting flowers – water droplets can mark petals, destroying the natural beauty of the blooms.

Fertilising

Premium orchid mixes contain enough fertiliser for up to six months from potting up. After that, apply a controlled-release fertiliser in late winter and again in early autumn when flower spikes are forming.

Give plants a boost every six weeks or so during spring and summer with a liquid or water-soluble fertiliser.

A teaspoon or two of garden lime once a year in winter will keep the growing mix “sweet”' (not too acidic).

How and when to prune an orchid

Cymbidiums and similar terrestrial orchids usually flower in spring. Flowering pots can be moved to outdoor living areas so they can be admired, or you can cut spikes of blooms and take them indoors.

Once the flowers have dropped, cut any remaining spikes off plants cleanly using sharp secateurs.

Diseases and pests affecting an orchid

 A healthy orchid will be reasonably pest-free, but you might find the occasional aphid or mealy bug. Apply a pyrethrum-based insecticide to control them if required. Watch out for slugs and snails when flower spikes are developing – they will demolish a spike of buds overnight. The orchid is susceptible to a virus that can cause black spots or stripes on leaves. There is no treatment for this, so it is best to discard it to prevent spread to healthy plants.

If you like this then try

Phalaenopsis: Moth orchid has spikes of showy exotic flowers from pure white to multi-colours; popular indoor plant.

Maidenhair fern: delicate bright-green fronds on fine black stems, excellent contrast to bold orchids.

Peace lily (Spathiphyllum): hardy indoor plant with glossy green leaves and white flowers.

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