CHAPTER VIII
WATERING EPIPHYTAL ORCHIDS
Success or failure with any class of Orchids depends largely on the exercise of discretion in watering. While it may be said that more specimens are lost by having too little water, especially among the smaller-growing species, than by over-watering, at the same time much mischief is caused by a system of giving a little watering frequently all the year round, and without any regard to the period of growth or rest through which the plants are passing. Such treatment does not provide for strong growth during the growing season, or adequate rest after the growths are finished; consequently the plants decline in health and the flowers are not satisfactory. Rain-water is the only suitable water for Orchids, and the growers who can command a supply of it all the year round possess a great advantage over those who have to use water from any other source.
During the period of growth and root action, too much water at the root cannot easily be given, provided the material in which the plants are potted is sufficiently porous and the pots or Orchid pans have a sufficient drainage. The rule should be to water thoroughly when watering at all, making sure that the whole of the potting material is moistened well, then not to give more water to that plant until the effect of the watering is seen to be passing, the plant being still moist but approaching dryness, when the thorough watering should be repeated. Nothing is more misleading than to pour a little water each day on the surface of the material in which the plant is potted. This is often considered to be careful watering, but it results in a large number of the plants never getting thoroughly moist at the root, while others in a retentive compost, or where the drainage is defective, become soddened. Such cases may arise occasionally under any conditions, and, where a thoroughly dry plant is found at a season when it should be moist, it is better to plunge the pot or basket in water until it is perfectly soaked. In the case of a plant which is too wet with stagnant moisture, it should either be repotted after the wet potting material has been removed, or placed on a shelf to remain without water until it is again in a proper condition to receive it.
In all cases a spouted watering-pot should be used. The rose watering-pot and syringe are necessary things in the Orchid house, but the use of them should be rigidly restricted to some definite work, such as watering Orchids for the first time after repotting, sprinkling the floors, staging, and brick walls, and other work which cannot cause mischief. It used to be a common practice to water Orchids overhead with a rose watering-pot, but the plants so watered made but few roots, and the foliage was generally unsightly, owing to deposits from the water. It is therefore best to make a rule against watering overhead in a general way.
The syringe may be used among Dendrobiums and some other warm-house Orchids during the height of the growing season; but it would be safer to arrange for such work to be done by means of a sprayer and at shorter intervals. The sprayer is a very useful and beneficial contrivance, and, in the hands of a careful operator using clean rain-water, it affords a valuable aid in maintaining a healthily humid condition in the atmosphere of all the Orchid houses, especially during the heat of the summer.
Equal in importance to the giving of sufficient water during the growing season is the observance of the dry, resting season, which, in a varying degree, is required by all Orchids, whether they come from hot or cold habitats, and whether they are epiphytal or terrestrial species.
WATERING TERRESTRIAL ORCHIDS
These, like the epiphytal Orchids, may be divided into two main classes, namely, those which lose their leaves annually, and those which are more or less evergreen. Some of the genera contain both of these classes, and notably the Calanthes. In C. vestita, C. Regnieri, C. rosea, and their varieties and hybrids the leaves turn yellow after the growths are fully made up, a sign which gives a good indication as to the necessity for withholding water for a lengthened period; while Calanthe veratrifolia and others of the class retain the last-made foliage green all the year round, the loss of foliage being in the old leaves, which should be removed at the first sign of decay. With these latter may be classed the Phaius, Zygopetalums, Cymbidiums, Cypripediums, and many others of evergreen habit, which require much care to be exercised in the matter of withholding water during the resting season, otherwise the plants will decline in vigour. After the growths are finished, most of these plants are benefited by removal to a cooler and more freely ventilated house for a few weeks, during which time the supply of water should be restricted, but they should never be allowed to suffer by being thoroughly dried. For Zygopetalums and other Orchids which it is customary to place in a rather drier atmosphere during the time they are in flower, such an interval would be sufficient rest.