How to Care for Your Orchids

Based on cultural instructions originally generated by McBeans Orchids.

Incorporating BMOS Members Suggestions.

CYMBIDIUM

Large flowered cymbidiums have been bred from species originating in the lower regions of the Himalayan Mountains, N.E. India, Nepal and Bhutan. Crossing larger flowered species and hybrids with small growing species from the Far East has produced the miniature cymbidiums.

FLOWERS

Modern hybrid cymbidiums, both large and miniature, produce a wide variety of colour forms some with contrasting colour in/on the lip ranging from spotting to colour blotches. Flower spikes carry from six to twenty plus blooms lasting for up to ten weeks or so, larger plants flowers last longer than the miniatures. Most of the miniatures flower during the autumn with a few exceptions while the larger types can flower autumn through winter and spring into early summer depending on type.

CULTIVATION

TEMPERATURE

Indoors during the later autumn through winter to early spring a daytime temperature of a maximum of 21 degrees C with a night temperature of between 11 and 13 degrees C. Ideally they should be grown outside during to late spring through summer and into early autumn where the day temperature can get quite high, try to avoid getting above 27 degrees C, but to produce flower spikes a large day/night range is needed with night temperatures of around 10-11 degrees C. Acclimatise your plant gradually when returning indoors or the change in temperature may cause spike loss.

LIGHT

Indoors cymbidiums need bright light, even direct sunlight during to morning or afternoon, i.e. east or west facing windows. During late December through January and into early/middle February as the light levels are low they will tolerate direct midday sun though this may shorten the life of the flowers of those that produce spikes late autumn through to early spring. Outdoors during summer etc they need bright light but preferably without direct sunlight. They will need a period of "hardening off" when moved outside more especially to light levels so place them in a semi shaded poison for 2/3 weeks before moving them into brighter conditions. (This is more especially true if instead of risking outdoor conditions your cymbidiums "over summer" in a cold greenhouse.

WATERING

Allow the compost to dry out at the top before watering but care is needed as cymbidium roots can rot if too wet especially during the indoor period. Outside and during the active growing period water more plentifully but never allow the plant to stand in water. Ideally rainwater is preferable but distilled water can be used and the occasional watering with tap water will do no harm.

FEEDING

Liquid fertiliser can be used quite successfully BUT at half strength i.e. where 10 drops to a litre is recommended use 5 drops. Fertiliser can "burn" orchid roots, which is why many recommend specific orchid feeds and perhaps once skill in growing orchids has been gained it MAY be worth trying them. Surprisingly cymbidiums will not produce flower spikes if they are too well fed so don’t feed during July and early August, (a plants aim is to reproduce but if it is happily growing away why should it bother to flower? Stress your cymbidium and it’s more likely to flower).

HUMIDITY

All orchids like humidity so when indoors place the pot on a saucer of gravel kept constantly wet to provide a microclimate BUT don’t let the pot base stand in that water.

COMPOST

Most, but not all, cymbidiums are terrestrial so try to match the soil conditions found naturally; multipurpose or John Innis type 1 mixed with Perlite or similar to provide free drainage works BUT then so does using absorbent Rock wool, and course bark mixed with fine bark.

POTTING

Re-pot only when you have to; when the roots have pushed the plant out of the top of the pot, when the pot is completely full or when the growing medium has deteriorated or soured (it will smell when damp if the compost has "gone off"). Use a size larger pot and, if possible, wash off all the old compost from the roots. Trim off any dry withered roots and only cut of old pseudobulbs if they are withered. If the pseudobulbs look dead but are firm leave them, as these are "back bulbs" which act as storage organs.