Orchid Plant Resting Period

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Blooming, Care and Culture, Growing Indoors, Growing Outdoors

Certain orchid plants require a resting period of about 6 – 8 months, especially if the plant begins to bloom in the winter or spring time. It best to water your orchids once a week during their resting period while kepping the lighting the same.

With the end of the flowering season for most orchid plants and with potting under control, the grower finds next that all orchids need a resting period—some going into such deep rest or dormancy that they ap­pear dead. In a state of nature this rest is provided by the change of seasons. It will be found that those plants requiring a long spell of complete rest in the greenhouse come from regions where long periods of hot wind occur. During such times these plants shrivel and dry, giving no sign of life. In the native habitat of many orchids these extremely dry seasons will be followed by tor­rential rains, during which the plant awakens and puts forth new growth that will culminate in bloom.

It is during the time of dormancy that collectors gather and ship orchids with the least danger of shock and damage. Many a plant has died en route, having been shipped after growth has re-commenced, when the fresh young roots and tender bulbs are easily broken or rotted. If shipped when completely dormant and dry, they will comfortably survive the long overseas journey and the fumigation, required on arrival.

By watching his plants, the grower will learn to recognize their needs. When the plant feels the need of rest, usually during the winter months, active growth ceases and the plant ‘stands still.’ There are no new roots and buds seem to remain endlessly in the sheath. Most orchids cannot be induced to break this dormancy until they are ready, but others, if conditions encouraging growth surround them when they normally rest, will begin premature growth. If this happens, the flowers will not have a chance to mature and the plant will refuse to flower for a season. For a weak plant this may be a good idea, but usually the grower expects a yearly flowering. Other plants, notably deciduous Dendrobes, will throw new plantlets if watered during the rest period. If a treat­ment inadvertently breaks dormancy, the amateur will be startled to find his collection increased by small additions, when what he expected was blooms.

Watching the roots is one means of judging a plant’s needs. Old roots that are still performing their special functions will be white and tough, and very hard to break. Dead roots turn black and wet or dirty-brown and dry according to the cause of death. If the plant needs to be removed from badly decomposed mate­rial and repotted, the roots may be green and slimy from fungus. But the most heartening sight to the orchid grower is the new roots of a plant awakening from rest. New roots, of a bright, clear, translucent green with a rosy glow, can be described only as jewel-tipped.

When plants are resting and the roots are inactive, it is only natural that they should require little or no water. They usually need more air, more sun, and less heat. In addition to these gen­eral rules, each of the genera, according to their native climate, has certain special needs.

The genus Cattleya is moderate in its demands for heat, air, and moisture at all times. It does not require complete rest. Withholding water from the pot for a short time after repotting or after flowering will suffice, but the bulbs should not be allowed to become dry to the point of shriveling. Humidity in the air and overhead spray will help keep them plump and firm. They should be well watered in the pot and then allowed to dry out until the pot feels light when weighed in the hand.

The ‘prima donna’ of the genus, Cattleya Warscewiczii or gigas, requires special treatment in resting; withholding water is not sufficient. If not properly handled it will put on new bulbs and leaves and refuse to bloom. Stern measures will be required to shock the plant into flowering. Cattleya gigas is one orchid that really demands neglect. When the new growth and roots start, the plant should be well watered until the new bulb is com­pletely made up—the flower sheath will appear at the same time, but without buds. The plant should then be placed in a very sunny spot and water withheld. Occasional overhead spray will meet all its needs during the winter months. As root activity be­gins anew and buds are formed in the sheath, watering may be gradually resumed and the plant moved to a warmer, shadier spot until after flowering. A slight rest may take place again after flowering before the new growth starts, and water should be used sparingly at such a time. Flowering takes place during the summer months.

The genus Laelia requires a great deal of light and air plus a more decided rest period than Cattleya. The plants should be hung against the glass in the sun after flowering. While growing they need much water at the roots. They thrive on extremes, heat and air in the daytime, and less heat and air at night. They should be kept in the sun and fairly dry during dormancy, but the bulbs should not be allowed to become shriveled.

The genus Brassavola calls for a warm temperature and copious amounts of water while growing and up to the point of flowering, which in most species takes place in autumn. After the growth is made up, during resting, less water will be the rule.

The genus Dendrobium, owing to its many locales, is as per­verse in its rest demands as it is diverse in its beauty. Rest is essential if the cane-like bulbs are to ripen and grow strong enough to bear the blooms. While the evergreen and the deciduous varie­ties follow the same cycle of maturation, rest, and flowering, means of securing rest differ.

One division of the evergreens comes from the rain forests of the tropics, where natural conditions encourage almost continuous growth. This division includes D. Phalaenopsis, D. dearei, D. thyrsiflorum, D. densiflorum, D. superbiens, D. bigibbum, and D. Farmed. They flower on the new growth and do not lose their leaves. As a result they can use some water at the roots at all times, with extra amounts during active growth. Temperature should be maintained at a minimum of 60° even during the rest period.

A second group of the evergreen Dendrobes comes from higher elevations and so requires less heat and plenty of light. Water will be given slightly less freely during resting, but it should never be entirely withheld. This group includes D. infundibulum, D. Jamesianum, and D. Formosum.

The deciduous Dendrobes, including D. superbum, D. nobile, D. Wardianum, and D. aureum, lose all their leaves during dor­mancy, becoming dry, shriveled, bamboo-like canes. They can be hung up against the glass and kept cool and airy, with water almost entirely withheld during the rest period. This treatment allows the canes to ripen and harden, strengthening them for profuse bloom. When the nodes begin to swell, indicating that the flower buds are set, the rest period is over and the plants should be given more heat, moisture, and shade.

The genus Oncidium needs a long dry rest after a well-watered growing season. It lacks pseudobulbs, but the heavy, leathery leaves are capable of storing food and water for the dormant period. There are exceptions to this rule among the family: O. candidum, O. crispum, O. flexuosum, and O. micranthum require little or no rest and should be kept moist at all times; O. Lanceanum must be removed to a cooler spot and dried out, although not completely, for a short time during the winter. All the other Oncidiums enjoy a scarcity of water during the rest period, with only enough moisture to keep the bulbs from shriv­eling.

The genus Cypripedium grows in a locale conducive to almost continuous growth. It has no pseudobulbs and its evergreen leaves make water at the roots a ‘must’ at all times.

The genus Cymbidium tends to produce vegetative growth if not rested properly. It should be watered more sparingly begin­ning at the end of August, and should be allowed to dry out fairly well between waterings. Always syringe overhead on sunny days, but make sure that the house dries out before night. The artificial feedings so beneficial during the growing season should be withheld from the time the new bulb is made up to the time when flowers appear. After flowering it may be resumed.

Cycnoches is a genus requiring special dormancy treatment. It goes completely dormant after flowering and water is completely withheld. If watered during the winter months, when the plant is dormant, it will succumb to rot and die. Much water is needed when the rest is over and the new bulb is being made up, but even then care must be taken not to allow water in the crowns. Flowering takes place immediately after new growth, usually in the summer.

The genus Coelogyne rests according to species, but all species require some rest. The condition of the bulbs is an accurate gauge of the needs of the plants. They should always be kept plump. Coelogyne Pandurata and C. asperata come from warm, moist, marshy habitats and so will grow most of the time in congenial environments. If the temperature can be kept at 6o° F., they will take water at all times. If the temperature is lower, the water supply can be cut down after growth is completed. Coelogyne cristata benefits from sun and reduced water supply during the resting period. It should be watered profusely while growing. Vanda is a pseudobulb-less genus. Growth is continuous. It appreciates a warm, moist condition, with slightly diminished water at the roots during winter. It requires little shade, since it seems to rest but little. When grown in good conditions, V. coerulea has an unusually fine root system for an orchid and will bloom prodigally, sometimes twice and, less frequently, three times a year. Vanda teres and V. Agnes Joachim seem difficult to bring to bloom in the temperate zones, their requirements for heat, intense sun, and much air being difficult to fulfil in a green­house. Vanda tricolor and V. suavis, whose roots require air and moisture at all times, are more easily accommodated. Vanda San-deriana requires more heat than V. coerulea and needs air and moisture at all times.

The genus Phalaenopsis is also pseudobulb-less, and, if properly nourished, will bloom constantly and never rest. When the pot­ting material is Osmunda, this tendency to excessive activity must be curbed or the plant will bloom itself to death. Buds can be pinched off unless at least one pair of the firm, leathery leaves have been formed since the last flowering. Old flower stems may break into bloom anew, which weakens the plant and should be discouraged by cutting stems close to the plant. The plant should be kept well watered, but the roots should not be allowed to be­come soggy from lack of air.

The genus Epidendrum rests somewhat, requiring slightly less water at the roots. It needs almost daily syringing, however, to prevent fatal drying out.

The genus Odontoglossum, native to elevated parts of tropical Central America, requires no rest. The roots must be kept moist at all times. Care must be taken to prevent the compost from becoming sour. Odontoglossum require more shade than most orchids.

Genus Stanhopea, on the other hand, responds gratefully to a period of rest after growing. Rest can be induced by allowing the roots to dry out fairly well and by providing plenty of light and air. When new growth starts, water in quantity is resumed. For most species blooming time comes in summer and should be immediately followed by a rest period.

The genus Miltonia is sensitive and delicate. Root activity is slight during damp winter months, so resting must be aided by very careful watering. The potting mixture, since the plants have very slight bulbs, must never be allowed to dry. They should be syringed with a fine mist because they chill easily. They are sus­ceptible to thrips in dry conditions. Humid air provides the an­swer to both problems.

To the amateur, each factor in the raising of orchids is likely to seem most absorbing and demanding in its turn. In reality all phases are equally important. Each factor must be right and must be combined harmoniously for perfection in growing and flower­ing. The grower will discover, as he watches and studies his or­chids during periods of rest and activity, that he is actually serving an apprenticeship to the orchids. No matter how much he may read or study, in the final analysis the surest way to success in orchid culture is through day-to-day acquaintance with the plants. Matters that appear mysterious or confusing at the beginning will soon become second nature. A habit of doing the right thing, a ‘green thumb’ or ‘orchid touch,’ will develop from this close re­lationship. Whatever it is called, it enables the grower to tell, when he enters the greenhouse, whether or not the air is suffi­ciently sweet and moist; to determine, by lifting or glancing at a pot, whether water is needed; to decide, after inspection of a plant, whether it needs repotting and the precise time for re­potting; and, finally, to determine with great accuracy how much or how little rest each plant needs.

Orchid Plant Resting Period

One Response to “Orchid Plant Resting Period”

  1. grace roman says:

    This is so exciting! I just attended a class in which I have been challenged to grow a few of these exotic plants. They are beautiful and great to give as gifts. love the turf look of your website.

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