The Garden Dickson, botanicus perfectus

The logo

Cymbidium Orchids

Summary

Growing cymbidiums is not too hard but remember that they do not grow in ‘earth’ as most other plants do.  Cymbidiums naturally occur in trees, in forest areas rich in decaying organic matter.  When growing in pots, adjust the conditions
to achieve the drainage they need.  The drainage hole in a pot used for an orchid should be enlarged to about 3 times the diameter of the usual hole.  Re-potting should be done in October or November, when flowering is finished.

Orchids require a very open, free draining potting mix and a specific orchid mix must be used when growing these plants.

Make sure your plants are in a position to receive only morning sun.  Cymbidiums are large plants and need a position where the leaves can spread out fully, so give them plenty of room.  Flower spikes are initiated with cool nights at the end of February or beginning of March.  When you see the first signs of a flower spike emerging from the base of the orchid, it is
useful to place a stake in the pot so that as the spike grows it can be tied for support and protection.  If growing them in a cold climate, ensure that orchids are under a covered structure, but receiving some direct morning sun.

The plant growth period for cymbidiums is October to February.

It is best to concentrate on applications of fertiliser which suit the stages of growth and flowering.  Most garden centres sell specific orchid fertilisers, one suitable for the growth stage, and one for the flowering stage.

Potting materials can be quickly ruined by poor watering methods.  Any alkaline water, such as bore water is totally unsuitable for orchids.  When to water depends on the growing conditions, the amount of shade, the temperatures, humidity and type of potting mix used.   Watering must be a personal, weather dictated operation.  Cymbidiums do not use great quantities
of water and it is possible to overwater in the growing period of October to February, just as easily as in the cooler and flowering part of their cycle, from March to September.  The possibility of overwatering is intensified by the use of plastic pots.  The only reliable way to is to check the potting mix, poke about in the surface of the mix.  If the mix is damp then the plant does not need water for a day or so.  If the mix is dry, then water thoroughly over the whole surface of the mix.   In hot dry weather you may need to water daily.

Growing cymbidiums in wire baskets with coconut fibre liners is quite successful for the home gardener as the water drains away much more readily and overwatering is not such a problem.

Monthly Guide

January

Generally hot weather so water around and over plant to humidify.  Don’t water too late in the evening and don’t allow roots to dry out, or overwater.  Feed fortnightly with specific orchid food for the ‘flowering
period’.

February

Very warm conditions so watch watering and provide humidity.  Feeding, watering etc, same as for January.  Fertilise with an application of blood & bone mixed with sulphate of potash (6 parts blood & bone to 1 part potash) and sprinkle this into the top of the potting mix.

March

Watch for flower spikes emerging.  Maintain same feeding and watering regime.

April

If there is any danger of frost, plants should be covered or moved indoors at night.  Plants still need to remain outside during the day in a position where they will receive morning sun.  Watering and feeding should be done only in the morning – do not overwater.  Continue feeding with ‘flowering’ fertiliser.  When flower spikes begin to emerge it will be necessary to prevent damage by slugs and snails as they can consume an emerging flower spike overnight.

May

Same as for April but feeding and watering should be reduced.  Carefully stake up flower spikes as they are brittle and easily broken.  Continue to protect from damage by snails and slugs.

June

Plants should now be moved to a more protected area to prevent damage from frosts, wind and rain.  This is the beginning of the ‘rest’ period for Cymbidiums so stop feeding.  Watch flower spikes for ants, aphids, scale, and spider mites.  Continue to watch for snails and slugs.  Water very sparingly and keep moist only if the plant is flowering.  Plants can be left indoors as long as they have plenty of light and air circulation, but not in a room which is too warm from a heating system.

July

Same as for June.

August

Remove any spent flower spikes.  Water sparingly – keeping just moist. Same as for June.

September

If flowering is finished, this is the time to re-pot if re-potting is necessary.

October  Check general health of plant and remove any damaged or diseased sections.  Use one of the mixes suggested on the first page  and re-pot the plant.  Sprinkle plant food around top of pot (dynamic lifter or similar).  Water the plant and place it in an area where it will receive morning sun and then dappled sun/shade in the afternoon.  Plants should still be protected from snails and slugs and should be up off the ground if possible.  Cover if there is any danger of frost.

November

Change to the fertiliser for the ‘growth’ period and feed the plant with this fertiliser at half strength every week.  Spray the foliage of the plant with the same half strength mix fortnightly.  If there is no rain, keep plants sufficiently watered and keep ground around them damp to provide humidity.  At the end of the month sprinkle 1 spoonful of slow release fertiliser on top of each pot.

December

Same as for November.  If hot, spray plant for humidity more often.

Ann Costelloe. The Garden, botanicus perfectus.