Caring for Orchids Over-Wintering and Resting
Caring for Orchids
Over-Wintering and their Resting Period
An orchid, for example needs to ‘rest’. An orchid is resting when it exhibits the least root and top growth activity, usually during the winter, and the degree of rest it requires varies considerably in this group of widely differing vegetative types. This makes it totally impossible to provide hard and fast rules. In one genus, for example, the species can vary one from the other in their needs.
The resting period often corresponds to the dry and either warm or cool period of the orchid plant’s own native climate. The ideal method for resting orchids is to have a resting house or resting section at least, but for only a small mixed collection grown all under one roof. There is usually a cooler end to a greenhouse or orchid house and this can be used to great advantage by placing the resting plants in this particular area.
Plants without pseudo-bulbs or tubers must not be rested as they are always active to some extent, and they do not have the food and moisture storage facilities provided by these specific parts of the plant. Examples of this type of orchid includes the slipper orchid, paphiopedilum, and the masdevallias. Vandas and aerides and other similar types of orchids, which have a continuously upward growing stem, regularly have thick fleshy leaves, which in nature are no doubt provided in order that the plant is able to resist drought. These plants should receive just sufficient water to keep the sphagnum moss fresh on the compost surface.
In general, all young seedlings which haven’t flowered, should be watered during all seasons, with due consideration given to the weather – this is vital in the caring for orchids routine. Other types of orchids with pseudo-bulbs or tubers will require to be rested during the winter — generally, the harder the leaf or bulb, the longer and drier the rest they require. Those types of orchids that are deciduous or semi-deciduous, require a more pronounced rest, for example, in the genus Dendrobium, the Dendrobium nobile and Dendrobium wardianum types in particular, will take a longer rest than the evergreen types of orchids such as Dendrobium thrysifolium. Most cattleyas and laelias and their hybrids too, need several weeks rest after they have flowered. Always keep a look out in case the pseudo-bulbs start shrivelling; a little shrivelling can be tolerated but this should never be so extreme that it affects the leading pseudo-bulb. Odontoglossums need not be rested in the same way as cattleyas, as a certain amount of moisture should always be present to some extent, except for very short periods.
An orchid house or greenhouse containing a small mixed collection of orchid plants, will normally have a lower winter temperature and this will help to provide the natural conditions that are required for resting. Attention must mainly be given to the frequency of watering the orchid plants. Careful observation of the individual plant will be the only way of checking this, and failure to rest may induce soft, weak, winter growths, which is always a setback for the orchid plant, and it subsequently takes a long time to regain its former vigour. While reducing the moisture in the atmosphere of the greenhouse should be a standard winter practice, avoid extreme conditions as an excess of dry heat can produce undue shrivelling of the pseudo-bulbs.
Discover more about caring for orchids: