GROWING ORCHIDS AT HOME

For many years orchids have enjoyed a reputation for being the most exotic of greenhouse plants. Their cultivation can be traced back to the middle of the last century when the first tropical orchids were brought to the western world. Now they have become the ultimate in houseplants.

As more and more people seek to grow something really different they are turning to orchids, and realizing that they can be grown with ease once their basic cultural requirements are understood. The modern hybrid orchid is the type most suited to the home. These have been bred over many generations, and are derived from the species, many of which are now very rare. The hybrids are tolerant plants which grow in a variety of surroundings with the minimum of attention, and reward the grower with large, flamboyant blooms. Many of the flowers last for eight to ten weeks.

A number of these hybrids are winter blooming, producing a fine display of flowers during the worst months of the year. By careful selection, it is possible to have blooms the year round. These plants vary tremendously in size and shape, and small and compact plants can be found to fit most window-sills. For sun rooms, there are the large-growing varieties which require good sized tubs and grow into enormous plants. 30cm (1ft) or more across and producing flower spikes over 90cm (3ft) tall. Many small species will grow in indoor growing cases. The whole orchid family is extremely large, but the plants that can be grown indoors successfully come from a very limited selection, and it is from the numerous hybrids from a few genera that the best houseplants are to be found – yet the choice is immense.

THE INTRODUCTION OF ORCHIDS

Tropical orchids were relatively unknown in the western world until the 18th century. Many famous names became involved with the introduction of orchids, among them Captain Cook and Charles Darwin. The first orchid to be classified was named Bpidendrum, meaning upon a tree. This species, now known as Encyclia

cochlccila, was then called Rpideiulruin cochleatum. It arrived in England in 1786 and bloomed the following year. It was not until the L9th century that collectors went specifically in search of new and hitherto unknown orchids. Early collectors were employed by the first commercial orchid nurseries, which came into existence to meet the demand for these new plants. There was a great rivalry between collectors, who stripped the orchids from the trees and despatched them in their tens of thousands – a regrettable onslaught. The losses of plants during their journey to England were tremendous. Also, many perished in the hot steamy greenhouses of the early Victorians. It was years before they realized that many orchids require cool and airy conditions. but gradually these requirements began to be understood as experience was gained through trial and error. In those early days, very high prices were paid for the finest specimens and the growing of orchids became a status symbol. During the first half of the 19th century. more and more new varieties arrived in Britain from the tropics. Each new variety caused more excitement than the last, and when they flowered. awards by The Royal Horticultural Society were showered upon the finest of them.

In 1856, the first man-made hybrid bloomed, and by 1885 so great had become the interest in orchids that The Royal Horticultural Society held the lirst-ever orchid conference in London. By this time, the hybrids were beginning to outshine the species, and while many of the imported species could now be acquired for a few shillings, the price for the latest hybrids could still be many guineas.

Around the turn of the century cal-anthes were the the great favourites. The Victorians grew them in their thousands and decorated drawing-rooms with their blooms during the festive Christmas season. Many hybrids were raised from them at that time, and a few are still available today. It was much later that the potential of the cymbidium hybrids was realized. Today, they are the most popular orchids in cultivation.

Orchids in the wild

In their wild state, orchids grow all over the world as epiphytes and terrestrials living in trees or on the ground. The most flamboyant are the epiphytes. which grow on trees – not as parasites but as air plants. This means they take nothing from the host tree, but merely take advantage of living in the air and using the tree as an anchorage. These plants have evolved in the warmer parts of the globe, where protection from cold is not necessary and there is constant moisture in the air. Therefore. their feeding requirements are meagre, and they exist on nothing but water and what can be derived from bird droppings and debris collecting in the axials of the branches. These epiphytes could not survive in colder climates where exposed roots could be damaged by frost, and it is in tropical forests that they have thrived in limitless quantities for millions of years. Most epiphytes produce pseudo-bulbs or false bulbs, which are swollen stems, at the base of the plant. These pseudo-bulbs enable the plant to store suflicient water for its needs, and will carry it safely through long periods of drought. Pseudo-bulbs vary considerably in their size and shape, but all form the same function. The bulbs carry the leaves. which can vary considerably in size and number. The bulbs outlive the leaves by several years, so that a plant will consist of bulbs with and without leaves at any one time.

A few orchids are deciduous and shed their leaves each year, retaining only the bulbs to sustain the next season’s new growth. This appears from the base of the last completed pcsudo-bulb and is followed by the formation of the new roots, which serve the plant in two ways. They are the means by which the plant can absorb moisture from the atmosphere. at the same time giving the plant anchorage on the tree. The flowers of these orchids may appear on long spikes from the base, from the apex of the bulb at the base of the leaves, or from the sides of the bulb, depending upon the type. These bulbous plants are known as sympodials. A further method of growth is adopted by some epiphytes, which consists of a

single vertical rhizome which is continually growing and producing leaves from the apex, which form in pairs each side of the rhizome. These orchids are referred to as monopodials. Another method of growth adopted by epiphytic or terrestrial orchids is known as diopodial. and produces a series of bulbless growths with broad, rounded leaves. The growths are joined by an underground rhizome similar to the sympodials. The number of terrestrial orchids (those which grow on the ground) probably outnumber the epiphytes (tree orchids). but they are generally less showy and are not cultivated to the same extent. Also, many do not adapt to cultivation as readily as the epiphytes. The typical terrestrial orchid has a single stem arising from underground tubers which serve the plant in the same way as the pseudo-bulbs of the epiphyte. These plants grow on grassy plains and in the cooler climates of the world, reaching almost to the arctic. Most of them become dormant during the winter or dry season, with a relatively short growing season.

CULTIVATION

The culture of orchids indoors is not so very different from that of other house-plants. and most of their requirements are easily understood. An orchid will continue to grow and repeat its annual cycle of growth indefinitely, and can be regarded as permanent. When large enough, they can be divided. although this should be done only if they become unmanageable – the larger the plant, the better the display of llowcrs. It is, therefore, a mistake to reduce a plant by too much division, and prevent it from flowering for a number of years.

Compost and potting One of the biggest differences between growing orchids and other houseplants is the type of compost needed. The majority of cultivated orchids are epiphytic. or have been bred from epiphytic species. For this reason, they must be grown in an open, free-draining compost. If you have not previously grown orchids, this may be the first time you come across bark compost. It is fir bark that has been ground down to form small chunks, and is sold by orchid specialists.

While this bark forms the basic ingredient of orchid compost, on its own it is too dry, and it is difficult to keep it evenly moist. Therefore, a small percentage of sphagnum peat is added. The more peat that is added, the wetter the compost becomes. Therefore, if you tend

to excessively water your houseplants, you would require very little peat in your orchid compost – and vice versa. In addition, a small amount of charcoal should be added to prevent the peat making the compost too acid, which can be observed by the appearance of green algae on the surface. Potting orchids in this compost is very easy, although it may take a little getting used to because of its unusual composition. Orchids are generally in need of repotting about every other year, and when repotted they should be given just sufficient room in their new pot to allow for a further two years’ growth. Overpotting is a big mistake. The plants will look unsightly and out of proportion with their pot, and there will be too much expanse of compost around the roots, which will remain too wet for long periods, resulting in overwatering of the plant. Therefore, always use as small a pot as possible and place the plant with its new growth facing towards the rim with space in between. A plant should be repotted when the new growth can be seen, about 2.5-5cm (l-2in) high at the base of the last completed bulb, usually during spring. An orchid is in need of repotting when the leading bulb has reached the rim of the pot and there is no room for the next growth. Alternatively, repot if the plant has pushed itself over the pot rim by an abundance of roots below. With monopodials, check whether the compost is firm and sweet. If a linger can easily be pushed through the compost it has deteriorated to an extent where it should be replaced. IUK the plant repotted.

Compost that has become sour – showing a green algae surface – also needs to be replaced. It is not always necessary to remove all the old compost before repotting. Very often, where there is a good root-ball and the compost remains intact, the plant can be repotted without further disturbance. Where the compost has deteriorated it must be removed by shaking it from the roots. Dead roots should be cut off and the longest of the live ones trimmed for easy insertion in the pot. A few leafless back bulbs can be removed at this stage. These are the oldest bulbs at the back of the plant, and they should be removed if there are more of them than green bulbs in leaf. Otherwise, they should remain on the plant. Deciduous plants with leaves on the leading bulb only can safely be reduced to four good sized bulbs without affecting the flowering of the plant. The bulbs should be removed by severing them with a sharp knife, through the rhizome.

When this has been done, the plant is ready for repotting. A layer of crocking material should be placed in the bottom of the pot, to allow for good drainage. Broken polystyrene tiles are ideal for this. On top of the drainage material place sufficient compost to allow the base of the plant to be on a level with the rim of the pot. The space between the plant and pot can then be filled with the compost and firmed down with the fingers. A potting stick is not necessary. The plant should now be firmly in place with the new growth sitting on the surface of the compost and not buried. After repotting, the plant should not be watered for a few days, giving the severed roots a chance to settle down. During this time, the leaves should be sponged daily or as often as possible until normal watering is resumed.

Watering

An orchid plant in growth should not be allowed to become completely dry at any time. The aim should be to keep the compost evenly moist, bearing in mind that it is very open and well drained. When watering, a maximum of water should be poured on to the plant, most of which will run straight through the pot. Therefore, make sure your plant has received sufficient water in one application. If necessary, flood the pot several

times to ensure it is thoroughly wetted. Overwatering in such an open compost is difficult, unless the plant is left standing in water, in which case it will quickly become sodden with loss of the roots through drowning.

Underwatering is far more common indoors where plants often dry out quicker in the drier atmosphere. The first sign of an underwatered plant is a shrivelling of the pseudo-bulbs, usually from the rear. In severe cases, the leading bulb will shrivel, causing a slowing up of growth and functioning of the root system, when the whole plant will become limp. From this stage, it will take a little time and continuous sponging of foliage to restore the leaves, while copious supplies of water to the roots will be required before they become active again and the bulbs regain their plumpness. Good, plump bulbs are the sign of a healthy plant: shrivelled bulbs are usually caused through underwatering. although it may be by overwatering. In the case of overwatering the roots drown in the sodden, airless compost and are unable to support the pseudo-bulbs. which shrivel from the lack of moisture supplied to them. In both cases, it is best to repot the plant which has suffered into fresh, damp compost immediately. paying careful attention to its watering requirements from then on.

Feeding

Orchids should be fed in moderation only. By their very nature they are unable to cope with large quantities of artificial feed. Feeding, therefore, should be kept to the minimum. Any phosphate or nitrate-based food is suitable for them. It should be given only during the spring and summer months, when there is sufficient light available to warrant the extra food supply.

Feeding should start gradually, as the days lengthen into spring, adding a liquid feed at about every third watering. This dosage can be increased during the summer to every other watering, with an additional foliar feed about once every ten days. As summer turns into autumn, gradually lessen and then discontinue all feeding until the following spring, when it can be resumed. Only strong, healthy plants should be fed. Do not feed sickly plants or newly-repotted plants until their new roots are showing.

Resting

Orchids that have completed a season’s growth and are resting will require little or no water during this period. When an orchid is at rest, all growth stops and the roots cease to take up nourishment for the bulbs. Some orchids have resting periods of up

to four months at a time, while others have so short a rest it can pass unnoticed. A resting orchid may discard part or all of its foliage at the commencement of its resting period, or it may retain all its foliage. Most of the orchids suitable for indoor cultivation are evergreen and retain their foliage for several years. They usually shed one or two leaves at a time from the older bulbs. Provided the bulbs remain plump when resting, there is no need to give water, but should shrivelling occur, particularly in the younger bulbs, one application of water is usually all that is required.

Some orchids may need two or three waterings over their period of rest, while others will need nothing until the new growth is seen. The commencement of this new growth indicates that the plant has once again started to grow, and normal watering can be resumed. Orchids that are resting should always be given as much light as possible. This is important, to ripen the bulbs prior to their flowering the following year.

Special tips

Most orchids are shade-loving plants and although they require sufficient light to induce normal flowering, they must not be exposed to direct sunlight through a glass window. This is far too strong for them, and yellowing of the foliage and possible sun-burn will result. Sun-burn will show up on the leaves as black or brown areas, and can only be removed by severing a leaf, which is not always possible with a plant that carries only a few leaves.

Insufficient light, however, may lead to non-flowering.

Greenhouse pests that attack orchids growing in greenhouses are not usually found in the home, and pests are very few and far between. More harm to plants can be done indoors when a plant is knocked over. Damaged areas will become wet and should first be dried with a paper tissue and then dusted with a sulphur preparation to assist drying. Many orchids retain their foliage over a number of years. As a result, old leaves will occasionally become ‘tipped’, showing black ends. This is usually no more than a sign of old age, and for appearance they can be neatly trimmed. Orchids dislike cold draughts and exposure to direct heat. Keep the plants well away from draughty areas and sources of heat. For example, do not stand plants over a radiator or the television set.

ORCHIDS FOR BEGINNERS

Of the whole orchid family, only a few types are in cultivation, and of those even fewer are suitable for growing indoors. The following orchids can be recommended as those most likely to succeed indoors. They are among the easiest to grow, and produce the most beautiful and rewarding flowers. Mow-ever. they cannot be grown all together. but are suited for different temperature ranges, and should be grown where conditions are suitable. Cymbidiums have long been regarded as the beginner’s orchid. In a greenhouse they are ideal, but indoors they can be rather space consuming and are best suited to a spacious sun lounge. Large plants can require up to 30cm (12in) pots, and the handsome plants produce rounded pseudo-bulbs, each carrying many long and narrow leaves. The flower spikes appear towards the end of summer and grow to a height of 90cm (3ft) and will require support from a long cane. The flowers, a dozen or more on a spray, come in all colours. from white, through pink to red. bronze, green and yellow. The lip is nearly always of a contrasting colour and these beautiful blooms will last up to ten weeks. They can be cut individually and worn for a special occasion, or cut as a spray and placed in water. Cutting off flowers reduces the strain on a plant. which will grow and flower better the following year.

Miniature cymbidiums are also available and are more easily coped with indoors. While they lack the bulkincss of the standard cymbidiums. they produce smaller flowers, every bit as attractive and in a multitude of colours. There is an extensive range of named hybrids, and the beginner may do better to order by colour choice rather than name. All orchid nurseries will have their own particular cultivars. Cymbidiums should be watered throughout the year and kept at a minimum temperature of 10 deg C (50 deg F). If they are-kept much warmer than this at night it may affect flowering. The maximum summer temperature may rise as high as 30 deg C (85°T).

Odontoglossums are wonderfully showy orchids; they make smaller plants than cymbidiums and can be accommodated in under 15cm (6in) pots. The odontoglossums are closely related to a number of other orchids, including cochliodas, miltonias and oncidiums. with which they will readily inter-breed to produce many different named hybrids. The most popular of these are odontiodas. odontomas, odontocidiums. wilsonaras and vuylstekearas.

These orchids are often collectively known as odontoglossum types. The main difference is that they are far more robust than pure odontoglossums and are ideally suited to indoor culture. They all produce neat, bulbous plants with a few leaves. The flowers are carried on long, arching sprays in a multitude of colours and colour combinations, often with several colours of dramatic design contained in one flower. Their flowering season is not regular and a well-grown plant can be flowered approximately every nine months. The large, attractive blooms can vary tremendously in their shape, and will last up to ten weeks at any time of the year. While a few of the species are grown the more robust hybrids are better suited for indoors. A minimum temperature of 10 deg C (50°P) is ideal, with shady conditions in the summer when the temperature should not rise above 18 deg C (0>5°1J) for any length of time. These plants should be watered throughout the year and fresh air is always important to them.

Cattleyas are the largest and most flamboyant of all orchid blooms. These plants are related to laelias, brassavolas and sophronitis. and intcrgeneric hybrids are available that combine the beauties of the different types. The most popular types are laeliocattleya. brassolaeliocatt-leya and sophrolaeliocattleya. The first two named produce large plants, often requiring up to 25cm (10in) pots, with stout, club-shaped pseudo-bulbs, each carrying one or sometimes two thick, broad leaves.

The flowers emerge from the top of the bulb at the base of the leaf, where they are enclosed in their young stage by a protective sheath. Several large, frilly

flowers are produced at a time, the colour ranging from white, through pink to the most beautiful mauves and purples, with yellow and green occasionally seen. The sophrolaeliocattleya types produce smaller plants, which can be contained in 15cm (6in) pots. Their colour is rich red and mauve hues. Cattleyas and their allies produce an abundance of thick roots, which will often trail out of their pot. but this is quite natural. They have two main flowering seasons, spring and autumn. although not all plants will bloom twice a year. Their blooms will last for up to three weeks on the plant. Cattleyas enjoy fairly warm conditions and their winter night temperature should not drop below 13 deg C (55 deg F) which can rise on summer days to 26 deg C (80 deg F). Their leaves should be sponged regularly, then they will keep a high gloss. They require a semi-rest during the winter, without allowing the bulbs to become shrivelled. The cattleya species are rare collectors’ items, and have no place in the home. Numerous line hybrids are available which have a built-in tolerance of indoor conditions. Paphiopedilums are the famous slipper orchids, and are among the most well-known and best loved of all orchids. The plants do not produce pseudo-bulbs, but have a series of growths, often with beautifully mottled foliage which makes them an attractive foliage plant when not in bloom. Their flowers are produced singly on a tall stem. Most of the cultivars suitable for indoors are not excessively large and can be accommodated in 15cm (6m) pots.

The handsome blooms come in a variety of colours and colour combinations.

These include green and white, purple and green, bronze and brown and pink and green. They are extremely long-lasting and can remain in bloom for over ten weeks. Their flowering period is mostly in winter.

Both species and hybrids are available. and they can be grown in a cool or warm atmosphere. The cool-growing types prefer a winter temperature of 10 deg C (50 deg F) while those requiring warmth (usually indicated by their mottled foliage), do best at a minimum of 1 3 deg C (55 deg F). They are shade-loving orchids. and should never be exposed to direct sunlight. They are ideally suited to indoor growing cases when they should be kept evenly moist all the year round. Lacking pseudo-bulbs, it is a mistake to allow them to become too dry at any time of the year.

Phalaenopsis are the beautiful moth orchids, whose beauty cannot be rivalled among the warmer-growing types. They are most suited to indoor growing cases, where a high temperature can be maintained. This should not drop below 18 deg C (65 deg F). to grow them successfully. The plants produce few leaves and never become too large. Their growth is monopodia! and one or two new leaves are produced each year. Strong aerial roots are often produced outside the pot. They flower on long arching sprays any time of the year, often blooming twice. Their colours are restricted to pink and white. The hybrids are more suitable than the species.

From this selection can be built up a line collection of indoor orchids, with a variety of bloom to flower throughout the year. This collection can be extended

with a few carefully-chosen true species. which are easily cultivated and have exceptionally showy and dainty flowers. The following orchids are of modest size, and all require cool conditions with a minimum temperature of 10 deg C (50 deg F). Coelogyne ochracea is a delightful plant that blooms in spring, and is grown for its fragrance. It produces sprays of small. white and yellow flowers. It requires a winter’s rest and plenty of light. Dendrobium nobile is a tall, caned plant that enjoys plenty of light and will bloom in spring with clusters of mauve-pink flowers along the length of its canes. It requires a winter’s rest and plenty ofgood light to grow well.

Brassia verrucosa produces graceful sprays of elegant, green flowers with long, narrow petals and sepals. Its fragrant blooms are produced in early summer. It requires a semi-rest in winter, for good results.

Vanda cristata is worth growing. Most of the vandas are hot-growing, sun-loving orchids with no place in the home. However, this small-growing species is the exception to that rule and can be grown in any well-lit position. Its striking green-and-red flowers are produced in clusters during spring and summer. It requires a slight rest during winter. Odontoiilossiim grande is a very striking species, producing its large, showy blooms during autumn. The flower spike may carry up to four bright yellow and chestnut-brown blooms. This plant likes a winter’s rest, when it can be completely dried out and given full light.

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