Moth orchids are an excellent choice for ‘first time’ orchid growers

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Moth Orchid. Image by Albrecht Fietz from PixabayMoth Orchid. Image by Albrecht Fietz from PixabayThe exquisite moth orchids are popular among novice and experienced growers alike because they are easy to grow and produce the elegant arching sprays of long-lasting blooms that can be seen in so many design magazines across the world.

The name Phalaenopsis is derived from the Greek and means "resembling a moth." It was so named because the white and pink species growing on trees in the wild resemble flights of moths at twilight.

Phalaenopsis is a genus of approximately 60 species of orchids from the tropics, but from widely diverse climates within the tropics. Some species come from seasonally dry areas in Thailand or Burma; while others are wet-rainforest species from the Philippines, Malaysia or Indonesia.  They are native throughout south-east Asia from the Himalayan Mountains to the islands of Polillo and Palawan of the Philippines, and northern Australia. Orchid Island off Taiwan is named after this orchid.

In tropical climates they tend to grow on tree branches and between rocks, usually near a source of water for moisture.  Aside from rainforest climates, they also grow in grassland areas such as pastures. These orchids are adaptable to many different types of environments which is one of the reasons they are so easy to maintain!

Most are epiphytic shade plants (epiphytic plants derive moisture and nutrients from the air and rain; usually growing on another plants but not parasitic on them;) a few are lithophytes (plants that grow on rock, deriving their nourishment chiefly from the atmosphere.) In the wild they are typically found below the canopies of moist and humid lowland forests, protected against direct sunlight, but equally in seasonally dry or cool environments. The species have adapted individually to these habitats.

Moth orchids were among the first tropical orchids to be grown in Victorian collections; and most of the Phalaenopsis plants offered for sale today are the result of many generations of breeding from species that are native to eastern Asia.  Because these hybrids are one of the easiest orchids to grow in the home and flower well under artificial conditions, moth orchids quickly became one of the most popular orchids sold as potted plants. Under optimal growing conditions, and once mature, these hybrids generally bear from twelve to twenty (and quite often more) flowers. 

Modern breeding programs have brought about enormous changes in plants for the mass market, with true miniature plants flowering in 6cm pots, to multi-floral types that flower several times a year, to large plants with enormous leaf spans and flower stems up to 1m long. There is a moth orchid for almost any culture, space, condition and colour taste. Besides the commonly seen pink and white varieties; advances in hybridizing have produced yellow, red and purple shades as well. Although many new hybrids are introduced every year, most Phalaenopsis offered for sale are unnamed hybrids and only specialist orchid growers will offer named species and hybrids.

Phalaenopsis schilleriana and Phalaenopsis stuartiana are two species that produce multitudes of flowers; and the small novelty types such as Phalaenopsis sumatrana, Phalaenopsis bellina/violacea, and Phalaenopsis lueddemanniana bear fewer flowers on much shorter stems. Phalaenopsis schilleriana produces deep rose-pink blooms flushed with white up to 8cm across, with silver-mottled dark green leaves. Phalaenopsis equestris produces clusters of 10 to 15 small pink flowers, each 2.5cm across, with fresh green leaves. Phalaenopsis cornu-cervi has spidery yellow flowers spotted with dark red, each 2.5 to 3.5cm across, in clusters of about 12 blooms that open successively. 

Phalaenopsis is a monopodial orchid that grows from a single stem. Orchids with monopodial growth often produce copious aerial roots that hang down in long drapes and have green chlorophyll underneath the grey root coverings, which are used as additional photosynthetic organs. Because they do not have a rhizome or pseudobulbs, the species adapted to dry periods by evolving fleshy succulent leaves instead. Flowers generally come from the stem between the leaves; and the plant produces about two sets of alternate, thick and fleshy elliptical leaves a year; the older basal leaves drop off at the same rate; so the plant commonly retains only four to five leaves all the time; if very healthy, they can have up to ten or more leaves.

In the Home & Garden:

Moth orchids are quite easy to grow, and generally like the light and temperature condition of our homes, making them an excellent choice for ‘first time’ orchid growers, and most suitable for city dwellers who have limited space. If kept in the home, moth orchids usually last two to three months, which is considered quite a long time; mature specimens grown in ideal conditions can bloom for much of the year.

The modern home is prone to all manner of insidious toxins, such as formaldehyde (from carpets, plywood, flat-pack furniture and insulation materials); benzene (from particleboard and some paints); propanol (cleaning products); and dichloromethane (paint thinners and strippers), whose effects can range from mild eye, nose and throat irritations to more serious conditions.

 We can all probably remember enough biology to know that plants take in carbon dioxide and give off health-giving oxygen and water vapour as part of the photosynthesis process. It might seem unlikely that mere houseplants could provide a defence, but studies have found some to be particularly effective.

Orchids in particular have the added advantage of being one of the few plants that produce oxygen at night, so the moth orchid is therefore highly recommended for bedrooms. It is also possible to grow moth orchids outdoors in warm frost-free and Mediterranean climates; and if properly cared for they can be among the showiest and most exotic of all garden or patio plants.

Growing moth orchids indoors:

When grown indoors it is pertinent to remember that in nature moth orchids are typically fond of warm temperatures between 20 to 35°C, but are adaptable to temperatures ranging from 15 to 35°C; at temperatures below 18°C watering should be reduced to avoid the risk of root rot.

Flowering is triggered by a night-time drop in temperature of around 5 to 6 degrees over 2 to 4 consecutive weeks, usually in the autumn. Moth orchids like high humidity (60 to 70%) so mist your plant regularly with tepid water and use a shallow tray of pebbles filled with water to increase humidity around your plants, but ensure that the pot does not sit in water. The higher the humidity, the more important it is to maintain a good air flow around the roots and leaves.  Keep in mind that temperatures close to the window on a windowsill will be colder or hotter than your general house temperature; and fluctuating temperatures can cause bud drop on plants with buds ready to open.

Phalaenopsis are low light orchids, and although light is quite vital to the well-being of the plant, ensure that it is not in direct sunlight as this will cause the leaves to burn. On the other hand, specimens grown in very dark areas tend to grow floppy dark green leaves and rarely flower. The leaves should be olive green; if they are darker it means the plant is not getting enough light; red tinged leaves mean the plant is getting too much light. Once the plant is in bloom you can place it anywhere in your home out of direct sunlight and draughts.

These orchids are usually potted in a well-drained bark mixture but can also be potted in sphagnum moss or mounted on wood. One of the most deadly blunders that new growers make is to overwater; and this together with bad drainage will cause the roots to deteriorate and eventually rot, killing the plant.

How often you water will depend on the potting medium and how much light and heat your plant receives. Bark retains less water than moss; so if your orchid is potted in bark watering once a week is generally sufficient. Moss retains more water, so watering will be less often, when the moss feels dry. During the growth season, water the plant whenever its exposed roots turn silvery white, usually weekly. During the flowering season, you can cut the water back to every other week.

 It is best to water in the morning and to wipe away any water which may collect in the centre of the plant to prevent crown rot. Use tepid water (rainwater is excellent) but do not use salt-softened or distilled water. Let the water run through the plant for a minute or so; and be sure to let the plant drain completely afterwards.

During the growing season, fertilise with a specialist orchid fertiliser as directed, but feed sparingly during the winter months. The plants do need the occasional 'flushing out'; so with every fourth watering use only plain water (with no fertiliser) to ensure that any potentially harmful accumulations of salts are leached from the potting medium.

When the blooms are finished, you can cut the spike down to the level of the leaves and the plant will bloom again within a year. You can also cut off the stem leaving two nodes on the stem (nodes are those little brown lines on the stem below where the flowers were.) One of these nodes should then initiate and produce flowers again within 8 to 12 weeks. Continue watering and fertilising while you are waiting for the blooming cycle to begin again. If a plant is large and healthy but does not produce flowers in a reasonable time, then reduce the temperature by 5°C for four weeks, and a flower spike will usually develop.

For healthy root growth, repot every couple of years before the potting mix has started to disintegrate. Do this when the plant has finished blooming but do not be tempted to repot into too large a pot, rather choose a pot just large enough to contain the roots. Do not try to bury the fleshy white aerial roots that extend above the pot, as they are prone to rotting.

phalaenopsishybriddphalaenopsishybriddGrowing moth orchids outdoors:

Moth orchids are epiphytes and cannot be planted directly in the ground outdoors; rather mount them on trees, wooden stumps or rocks, or grow them in containers, hanging baskets, or raised beds, filled with a potting media specifically formulated for these orchids. When mounting or planting your orchids take extra care to make sure the plants are tilted so that water quickly runs out of the crowns.

Growing plants in sphagnum moss in slatted baskets is another very successful way to cultivate moth orchids outdoors, because for those species that want extra moisture the roots will stay inside the moist moss; and for those which require drier roots, the roots will naturally head out onto the basket surfaces and sometimes even grow completely outside the moss.

Moth orchids scorch easily in the sun and should be grown in good light but complete shade. Although they like good ventilation around their roots and leaves, they will need protection from strong winds and excessive rainfall.

Moth orchids grown outdoors will also need regular watering during dry periods and fertilising with a specific orchid food. Some of the hybrids and speckled-leaf species like more light and less water than some of the green-leaf hybrid types. In all cases Phalaenopsis like filtered light, dry leaf crowns, and good aeration at the roots. While regular watering is appreciated, wet and soggy roots systems and media are to be avoided. Successful growth means finding the right balance between humidity, temperature, light and air flow.

Propagation:

Sometimes small plantlets (keiki) appear from the nodes on the flower stems. Detach the plantlets when they have developed several good roots and pot them up in orchid mix. Water sparingly at first, but mist spray daily. Production of offsets can be encouraged by application of keiki paste (a specialist hormone preparation obtained from specialist orchid suppliers) to the nodes of the spent flower spike. Ordinary hormone rooting compound will not do. With a scalpel make a vertical cut through the bract covering the node. Do not cut into the bud beneath. With tweezers pull away the two halves of the bract and apply a little keiki paste to the exposed bud. After six to eight weeks little plantlets may be produced.

Pests & Diseases:

If grown correctly these orchids are more pest free than most genera, but watch out for spider mites, thrips, scale, mealy bugs and aphids.

Problems:

Bud blasting is a common problem with Phalaenopsis, but fortunately there is almost always a reason that can be determined for this condition. There are many factors that can cause buds to dry up and drop off the plants without ever opening.  Check that the room you are growing your orchid in is not excessively hot and dry or the light level too low. Also, ensure that you are watering correctly and not over fertilising. The plant also dislikes cool draughts and very strong fumes emitted from fresh paint, carpets, refinishing woodwork, etc.

Toxicity:

The moth orchid is non-toxic to humans, dogs, cats and horses, but it is always advisable to supervise young children and pets around plants.