Also known as the boat orchid, Cymbidium (sim-BID-ee-um) hybrids descend from species originating mainly in the Himalayas, the mountainous regions of India and China. They can also be found throughout the Far East: through Japan, Philippines and Australia.

Cymbidium orchids are large evergreen plants; they have “strappey”, grass-like leaves shooting from pseudo-bulbs at the base of the plant. They are clump-forming and have fleshy roots.

Cymbidiums are usually grown in conservatories or cool greenhouses. Different varieties flower between September and April. There are two main types of Cymbidium, standard and miniature. Standard Cymbidium – differentiated from miniature cymbidium by the size of the pseudo-bulbs and flowers – prefer cooler conditions to miniatures.

Flower spikes are produced in autumn or winter from the newest pseudo-bulbs. Initially they look like leaf growths but the flower spikes tend to be rounder at the tip and more fingerlike than leaf growths. A flower spike may carry 1 to 30 blooms depending on the variety

Temperature: When in flower, Cymbidium like cool house temperatures of between 15-20°C. The warmer they are kept, the shorter the flowers will last.

In summer, when the plants are out of flower, they need hot bright days (25-29°C) and cool nights (10-15°C) to initiate flower spikes. This can be achieved by setting the pots outdoors during summer under dappled shade away from midday sun, (to avoid leaf burn). Feed and water regularly during this period. The plants should spike up when the temperatures fall in the autumn to below 10oC. Bring the plant indoors before the first frost. Once the plants have formed their flower spikes and the buds are well developed they can tolerate slightly warmer temperatures of 15–20°C.

Note: To help prevent flower and bud drop, keep plants away from drafts, radiators and other heat sources.

Light: Cymbidium like plenty of light in the summer, but not full sun. A combination of long hot days and cool nights during July and August will initiate the flower spikes. This is also a good time to feed the plants with a high potassium feed or “bloom booster”. Plants need less light when in bud and/or bloom during the winter.

Note: Direct sunlight can burn the bloom and leaves.

Note: Never stand the plant in water for more than 10 minutes.

Feed: As orchids go, Cymbidium are quite hungry and require regular feeding to produce good flowers. Feed once a week during spring, summer and autumn using a balanced orchid fertilizer, such as Ivens Orchids’ Orchid Feed, and once every two weeks during the winter. A high potassium feed or “bloom booster” can be applied from July to September instead of the balanced feed.

Air Humidity: Good ventilation (not drafts) and moist air are essential. The humidity can be raised by placing the plant on a tray of moist gravel or pebbles. 50% humidity is ideal.

After Flowering: Cymbidiums will not flower if kept too warm or with insufficient light. They flower once a year and usually for at least six weeks. Once flowering is over, cut off old flower stems near to the base. To initiate the next flower growth they must have cool nights throughout the spring and summer months. Stand your plant outside towards the end of May until the middle of September. Stand the plant on a slightly raised base to avoid slugs getting into the pot. Early morning sun is ideal but provide some shade against strong sunlight. Remember to continue feeding the plants during this period.

Repotting: Repotting and dividing are best done in spring after flowering but only if your plant has outgrown its pot – Cymbidium like to be very restricted in their pots. A specimen plant can be produced by potting up regularly. A larger plant usually produces more spikes but sometimes a plant that has been mistreated or just becomes too old may benefit from dividing as this may regenerate it. Use orchid compost, such as Ivens Orchids Cymbidium Compost, that is moderately free draining whilst retaining some moisture. Repotting and dividing classes are available from Ivens Orchids.

Basic Repotting Technique: Cymbidium are tough plants and repotting them, and especially dividing them, can be a very strenuous job; you will need a strong knife and sharp secateurs.

Tap plant out of its old pot or if very pot-bound you may need to cut the pot away; the plant will be easier to remove from the pot if it is dry. Inspect the condition of the root-ball: In a healthy plant, the pot should be almost completely full of firm creamy roots with pale green growing tips. Generally, a cymbidium will grow in one direction so it will have a “back”, (where the oldest growths are,) and a “front”, (where the youngest growths will shoot). If you can see a directional trend in the plant to be potted bear this in mind when positioning the plant within the pot and allow space for the new growths to develop without making the plant look lop sided. Use a pot big enough for you to get two fingers around the root-ball between the roots and the inside of the pot. Holding the plant upright, feed compost around the root-ball; there probably isn’t a lot of room between the roots and the sides of the new pot but pack in as much compost as you can, making sure it goes right to the bottom of the pot where you want the new roots to grow.

Cymbidium can be potted firmly. Always dampen down the compost before potting and water as normal after repotting

Dividing: A plant that needs to be divided will be large and old with many pseudo-bulbs. Some may be so old they no longer carry leaves; these are known as back-bulbs and are useful to the plant as storage organs for water and nutrients. The plant may also have bulbs that are black and soft; these are no use to the plant and must be removed. When dividing, look at the plant to see if it shows natural breaks between the growths where it could be divided. The intention is to divide the plant into two or three good sized plants that have at least 3 or 4 pseudo-bulbs. Tap the plant out of its pot as described in ‘Repotting’ above, then cut through the plant using a strong sharp knife, trying to avoid cutting through a bulb or new growth. Once you have your divisions, shake off any loose compost teasing out any dead or loose bits and remove any old, brown, soggy or damaged roots. Also remove any old black or soft bulbs, cutting them away if necessary. The live roots that are left can now be trimmed to about 10 to 15cm; this will help prevent damaging them during re-potting and allow the plant to regenerate. Do not worry that it looks to be a large amount of root to remove; a healthy plant will very soon develop new roots and the plant will benefit by repotting in this way. Using a pot big enough for the next year or twos growth, support the plant with the oldest pseudo-bulbs, (the “back”,) at the edge of the pot and the “front” of the plant toward the centre of the pot. Cover the base of the pot with a small amount of compost then feed fresh orchid compost around the root-ball. Always dampen down the compost well before potting. Firm the compost with your fingers as you go.

The plant should not be watered for 2 weeks after dividing; thereafter the leaves may be lightly misted and watered sparingly over a period of about 8 weeks. This allows the new roots to develop and search for moisture within the compost stimulating good root growth; over watering would cause the plant to rot. Regular watering and feeding can resume once the plant starts to feel secure in the pot and new top growth can be seen.

Although dividing may sound drastic, provided it is done early in the growth season, (ideally March or April,) the plant will have sufficient time to produce new roots and still flower in that season. This is one of the reasons why the plant should not be over potted: i.e. the bigger the pot, the more energy the plant needs to make roots and the less energy it has to flower.

Handy Tip: A leafless back bulb can also be removed and propagated by potting up in its own, very small pot.

Pests: Prevention is always better than cure so look for good healthy plants to start with and keep them that way with a clean environment for your plants. Throw away old, weak or infested houseplants and maintain good housekeeping in the greenhouse. Most often seen pests are scale insect, aphids, red spider mite and slugs. All of these will weaken the plant if left unchecked. If found early enough, the scale and aphids may be cleaned off with soapy water, otherwise, treat with a specific systemic insecticide.

Buying Tips: Always buy good quality orchids from a reputable supplier and look for clean healthy plants. If buying plants in flower, check the flowers are not damaged and that the pollen caps are still on the flower, (if these get knocked off by poor handling or contaminated by poor storage or transport conditions, the flowers will very quickly discolor or “go over”. Unless you have ideal transportation and growing conditions, buying a plant with immature buds may be a mistake as some plants can be sensitive to being moved during the early stages of flower development. Look for plants whose flower buds look quite plump and ready to open. Don’t be afraid to buy a plant whose flowers are nearly all out, especially during the cooler months. Providing they are not kept too warm, Cymbidiums stay in bloom for many weeks even once all the flowers have opened and give a marvelous display.

Handy Hints: Keep your plants clean and healthy by occasionally cleaning the leaves with a mixture of 1 tablespoon of olive oil and a few drops of washing up liquid mixed in about 300ml of warm water. Using a sponge cloth, wipe over the leaves with the mixture. As old leaves die they fall off leaving behind dry brown bases. These can be removed by stripping or pulling away from the pseudo-bulbs. This helps to make the plant look tidy and prevents bugs from hiding around the plant base.

article by IVENS ORCHIDS

Click on to link: www.ivensorchids.co.uk

Dendrobium Sw.

Dendrobium (den-DROH-bee-um)

Subfamily: Epidendroideae

Tribe: Dendrobieae

Subtribe:Dendrobinae

There are about 900 species, in India, China, S.E. Asia, Japan, Malaya, The Philippines, New Guinea, Australia and the Pacific Islands including New Zealand.

The name is derived from the Greek dendros (tree) and bios (life), referring to the aerial epiphytic existence of most species. Dendrobium was established by O. Swartz in 1799 in Nova Acta Societatis Scientorum Upsaliensis p.82. It does not make good reading as it is in botanical Latin!

Dendrobium is a diverse genus of orchids with different cultural needs. Many go througha growth phase and then a rest phase during the course of a year, and must be given water and temperature to match these periods of growth and rest. Flowers can last one day to many weeks, depending on the type. Owing to the extreme diversity of the genus, there are about 10 main groups; the writer has categorised culture according to the following main types as found in amateur houses:

PHALAENANTHE

Evergreen for several years, with thin, tall pseudobulbs, terminal inflorescence (flower spike at top of cane), usually appearing in the autumn or twice a year (see culture). Species such as Den. affine, Den. bigibbum (phalaenopsis), Den. Dicuphum and Den. Williamsianum.

CULTURE

Grow warm all year round; 60F nights; water and fertilise heavily when roots appear after growth finishes. If a short cooler (55F) dry rest is given, then the plant may be ready for another growth, which may mature during winter and flower in the spring. Treat this growth as a summer growth cycle. These grow well with phalaenopsis, except for the rest period. Plants will go deciduous if grown too cool and dry.

SPATULATA (Antelope type)

Evergreen for several years. Most are large, vigorous plants with long-lasting flowers in summer to several times a year. Species such as Den. antennatum, Den. canaliculatum, Den. discolor, Den. gouldii, Den. johannis, Den. lineale (veratrifolium), Den. stratiotes, Den. strebloceras and Den. taurinum.

CULTURE

Warm all year (60 to 65F nights, 75 to 90F days); no rest period; can be kept cooler in winter if dry; medium to high light.

DENDROBIUM

Most of the plants are pendulous, with leaves all along the canes that most often drop with onset of cooler, drier weather. One to five flowers per node are borne from the nodes of the leafless canes in mid-winter through to early spring.

GROUP 1

Species such as Den. chrysanthum, Den. friedricksianum, Den. nobile including varieties, (of which 11 have been described in a Victorian orchid book) and wardianum.

CULTURE

Growth period in summer; give warmth, water and fertilise heavily from when roots appear until top leaf appears on canes. Then give high light, no water, or fertiliser, cool nights (40 to 50F). In other words, forget about them. I had a plant of Den. Nobile var.cooksonianum (the peloric form), which was put on a high shelf for its winter rest. Totally forgotten and discovered 6 months later, still green but very shrivelled. It was watered and the canes plumped up and the plant flowered extremely well.

GROUP 2

Species such as Den. anosmum (superbum), Den. crassinode, Den. falconeri, Den. fimbriatum, Den. findlayanum, Den. heterocarpum (aureum), Den. loddigesii, Den.moniliforme, Den. parishii, Den. primulinus and Den. transparens.

CULTURE

Same as Group 1, but winter nights 55F. Deciduous species need virtually no water or feeding in winter, and maximum winter light.

CALLISTA

Most are pseudobulbous plant with pendant inflorescences.

Pictured above is Dendrobium thyrsiflorum as grown by the author. The plant can be found in N.E. India, Burma, Thailand and Laos at altitudes of between 1100-2300m (3630-7590ft.) or higher. Hence it can be grown well in the cool house.

Species such as Den. aggregatum (now properly lindleyi), Den. chrysotoxum, Den. densiflorum, Den. farmeri and Den. thyrsiflorum. Some of these look and grow well mounted on bark, but some only last 7-10 days in flower.

CULTURE

Summer give warmth (60-90F), medium light, medium quantities of water and fertiliser. Winter keep cool (50F) nights, medium light, just enough water to keep pseudobulbs from shrivelling, no fertiliser.

LATOURIA

Leaves at top of pseudobulbs are large and leathery, inflorescence erect, flowers commonly yellow-green. Species such as Den. atroviolaceum, Den. macrophyllum and Den. spectabile. Generally long lasting flowers, especially atroviolaceum.

CULTURE

Same as antelope types, but cooler and drier when resting in winter.

FORMOSAE (Nigrohirsutae Type)

Canelike pseudobulbs, with black hairs on leaf sheaths and pseudobulbs often apparent, leading to the popular name nigrohirsutae. Flowers usually white, up to 4 inches across, two to three together from near the end of the pseudobulb. Long lasting. Species such as Den. bellatulum, Den. dearii, Den. draconis, Den. formosum, Den. infundibulum, Den. lowii, Den. lyonii, Den. margaritaceum, Den. sanderae and Den. schuetzii.

CULTURE

Intermediate to cool all year round, 50 to 60F nights, maximum 85F days. Water and fertilise when growing; give a slight short rest (dry) when growth is completed. Keep barely moist until growth starts again. New growths are prone to rot if kept wet. Most new growths, in general, are like small funnels, which trap water. Beware of this.

What plants need is good air movement at ALL times. Use large oscillating fans, like ones used in offices. Just be careful with water and keep them on constantly. The airflow should give the plants slight movement and a reduction in fungal and related diseases. When mentioning fertilising heavily, don't add a lot of feed at one watering. Fertilise 3 times in 5 at half strength as stated on the container. Use high nitrogen feed from spring (or start of growth) to August, and then use high potassium feed. Stop feeding in winter when growth has finished or flowering has stopped. Use any type of fertiliser. There is no secret or special formula to feeding orchids. Please try growing some Dendrobiums. They are well worth it.

Peter Fowler

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Disas

The South African orchid. Disa Uniflora and its hybrids, produce some of the most beautiful flowers in the orchid family. The flower range from white through to red, pink, yellow and orange. The flowers can last up to ten weeks in flower.

Disas produce a rosette of leaves, which if the plant is large enough will produce a flower spike. After the flowers have finished, you will see lots of offshoots around the base of the plant, then in September these can be removed and potted on separately. The old plant will eventually go yellow and die but not before producing many new plants.

LIGHT Disas need adequate light to produce strong plants and flowers, but their roots must be kept cool at all times. They can make an ideal window sill plant, but be careful that the sun does not burn the foliage.

WATER. Water quality is very important to successful culture; always use deionised or rainwater only. Never use tap water on Disas. Always stand pots in a tray or dish of water and replace every two to three days. Never let plants dry out. In the summer months they drink a lot of water, the colder the water the better. You can add a very weak fertilizer to the water every month in summer. I never feed in the winter months, I also stop feeding when the flower spikes start to show. Many disas are lost by too much feed.

TEMPERATURE . Disas are very forgiving. They will grow in and survive hot spells of over 100 derees F, they will even take a light frost, but they do better if the temperature is cold, around 45 to 50 F minimum night temperature.

AIR . Good air circulation is beneficial to Disas. You can put them outdoors in the summer, but remember to stand in dish of rainwater.

REPOTTING. This is best done in September. Carefully remove plant from pot and wash all the old compost from the plant. Separate all offshoots, being careful not to damage the roots, then plant into clean pots one plant per pot.

COMPOST. I always use 1 part Sphagnum moss peat and 1 part perlite, and 1 part fine washed grit. You can use New Zealand Sphagnum Moss but you will have to be careful when repotting as the roots can be a job to separate from the moss without damage.

PEST. Disas can be affected by whatever pest are present in you collection. Aphids can attack flower buds and flowers. A weak spray of Malethian will help

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Miltonia

Miltonia Lindl. & Miltoniopsis Godefroy-Lebeuf

Miltonia Lindl.

Say (mil-TOH-nee-ah)

Subfamily: - Epidendroideae

Tribe: - Oncidieae

There are about 10 Miltonia species found mostly in Brazil. The most commonly grown species are Miltonia clowesii, cuneata, regnellii and spectabilis.

The name is dedicated to Earl Fitzwilliam, Viscount Milton of Wentworth House, Yorkshire and was established in 1837 by John Lindley in The Botanical Register.

Some species previously referred to Miltonia have been removed to the segregate genera Miltoniopsis and Miltonioides.

Miltoniopsis Godefroy-Lebeuf

say (mil-toh-nee-OP-sis)

A small genus of five species exist in Costa Rica, Panama, Venezuela, Ecuador and Colombia.Those generally grown are Miltoniopsis roezlii, phalaenopsis and vexillaria. The name refers to the resemblance of the flowers to those of the genus Miltonia.

The genus Miltoniopsis was established by Godefroy-Lebeuf in 1889 in Orchidophile (9:p.63). However, subsequent authors failed to refer to this name and four of the five species remained in the genus Miltonia. In 1976 L.Garay and G.C.K. Dunsterville in Venezuelan Orchids Illustrated, described a new species as Miltoniopsis santanaei, resurrecting the genus as described in 1889. The species for this genus are treated as Miltonia for hybrid registration purposes.

CULTURE

Miltonia, including Miltoniopsis.

These fabulous orchids are commonly known as pansy orchids, owing to their similarity to pansies and are being grown more and more now as you can buy them from your local garden centre (although mostly they will not be named).

Miltoniopsis are cool-growing orchids that originate in the higher elevations of the Andes in Colombia, Panama and Ecuador. The warmer growing species, the genuine Miltonias, originate from the Minas Gerais area of Brazil and more closely resemble large-flowered oncidiums. The flowers can be wonderfully patterned.

LIGHT

The plants should be relatively shaded about the same as Odontoglossums or slightly less. I could quote Foot-candles, but do they mean anything to most growers?

The warmer-growing types prefer more light than their cooler-growing relatives.

 

 

TEMPERATURE

This criterion is critical. Unless the temperature is kept under 85F, they may not flower.

The minimum is 50 to 55F, thus they are thought of more as intermediate growers; and can be up to 90F for the warm growers. Humidity should be 70-75%. Air movement is VERY important. Have a fan going 24/7, just to move the leaves slightly. I have found a £20, 18” fan will last 3-4 years, which is pretty good going.

WATERING

This should be plentiful and the growing medium should drain perfectly. They are not heavy feeders and will not tolerate salt build up. Feed 1 in 4 and leach heavily with water every 4^th watering. I use a high nitrogen feed in Spring/Summer and a high potassium tomato feed in autumn for a couple of months. Let the plants nearly dry out between watering, as you would Cattleyas.

If the humidity is wrong along with the watering you can get the well known pleating of the leaves. We have all experienced this!

When it comes to compost I use a foam/fibrous peat mix which they were growing in, when purchased. The compost can be purchased from Mansell and Hatcher. I have been using this compost for 3 years now and am very happy with it, but you need to repot every 18-24 months, maximum.

It is never too late to start growing Miltonias. I had been growing orchids for 18 years before I gave them a go. Of course most Miltonias /Miltoniopsis plants purchased are hybrids now, as the species are becoming quite scarce. The colours and patterns of the better hybrids are a sight to behold. When in flower try to keep water off of the flowers else they will discolour, overnight.

© Peter Fowler 02/03☺

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Odontoglossums

Odontoglossums are a member of the sub-tribe Oncidiiniae. Their natural habitat is mostly to be found in the mountains of Central and \south America, flowering high in mountains between 5000 to 9000 feet where apparently the rainy season is almost continuous. As the temperature falls at night mist envelopes the region, leaving the plants moist with dew and humidity.

They are considered to be among the most beautiful orchids with their many flowers on long spikes.

Culture to be considered in this country, is attempting to match their cultural environment, a greenhouse seems to be ideal. Like all plants they require food, water, light and air, also protection against extreme temperatures, pest and diseases. Water should be fresh rainwater. Feeding with any orchid fertilizer, to make watering level of approx. 450-500µS, the ideal PH level seem to be 5.5-6ph.

They seem to like a fairly reduced light level of about 50% shading in the summer. Gentle air movement should be created with fans in the greenhouse.

Odontoglossums are epiphytic and thrive in compost that is open and free draining. The roots enjoy growing in the open spaces; they detest stale damp compost. Bark, sphagnum moss, perlite or rockwool seem to be the ideal types of media

Odontoglossums are cool growing orchids and cool temperatures should be considered, minimum 12°c. Humidity must be created as far as possible to match their natural environment. Damping down the floors with water will help with this.

In all Odontoglossum collections there seems to be a special place for the species of the genera.

Albert Fetherston

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Lycaste

Lycaste is one genus in a group of genera that belongs to the sub-tribe Lycastinae. Another in this sub-tribe is Anguloa. Lycaste were introduced to Europe sometime between 1795 and 1800. It was George Ure-Skinner who brought most Lycaste to Europe from 1840 onward, and it was he who introduced the beautiful Lycaste Skinneri. The Lycaste was originally classified in the genus Maximillaria and it was at about 1843 the Lycaste was so named by John Lindley. Classification of the whole group from which Lycaste is associated is complicated and still hotly disputed.

There are 45 species although new Lycastes are still being discovered. Their natural habitat is the north to mid western region of South America. They grow between sea level and 700 feet and are epiphytic with large leaves on oval pseudo-bulbs. There are many stunning flower colours.

Cultivation: A greenhouse is ideal. Compost should be free draining, sphagnum moss and perlite seems to suit them. Plants should be kept on the dry side when the bulb is made up. Tomorite is ideal for feeding, as well as other Orchid feeds. Fresh rainwater should be used with the feed to make up to 300µS, with PH of 6. Humidity of 45-55% with 50% shade during the summer months. Oscillating fans also help keep airy conditions, with minimum night temperature of 50-60ºF.Waterlogging in new growth may cause damage, so care should be taken when misting or watering.

Albert Fetherston

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  Paphiopedilum

THE GENUS PAPHIOPEDILUM

Exactly how many species there are in the genus Paphiopedilum depends on to whom you speak. Excluding varieties and forms, it is commonly accepted that the number is between 65 and 70.

All Paphiopedilum, or Paphs. for short, are characterised by a cup-like lip reminiscent of a moccasin, or slipper, hence the familiar term “slipper orchid” or “lady’s slipper”.

Paphs. are mainly terrestrial (ground- or forest floor-growers) although a few, such as P. lowii, are usually found growing on the surface of rocks or perched in the cleft of tree branches. They are divided into two cultural groups; warm growing, mottled leaf types like P. Maudiae (ideal for beginners) and the cooler growing green leaf P. insigne types.

TEMPERATURE & HUMIDITY

Green leaved Paphs. ideally require a minimum night-time temperature of approximately 12ºC (55ºF) while the mottled leaved types prefer it a little warmer (16ºC, or 60-65ºF). Daytime temperatures should range between 22 ºC (70-80ºF) - however, short periods of higher temperatures will not harm the plants provided there is a good variation between night and day.

Humidity should always be around 60-65% during the day but at night such high levels should be avoided in case they lead to a possible onset of bacterial rot.

LIGHT & AIR MOVEMENT

For optimal growth throughout the year Paphs. enjoy a medium light intensity of about 1,000 - 1,500 foot candles. Direct sunshine should be avoided, except for early in the morning before it has any real strength. If the plants are being grown indoors do not place them on south- or west-facing window sills directly in front of the glass, as this acts as a magnifying glass and the plants will burn and dehydrate. Use a table or sideboard a few feet away, or cast some beneficial shade by the provision of blinds and/or net curtains.

Moist air and vigorous air movement at room temperature is highly recommended to keep plants healthy. It also helps to reduce the spread of disease by keeping the surface of the leaves dry. Be warned that hot and cold draughts can cause bud-blast (i.e., the buds turn brown, shrivel and die before they open).

WATERING & FERTILISING

Paphs. do not have pseudobulbs like Cymbidiums or Dendrobiums, and therefore must be watered regularly - no rest period required. Keep the compost moist (not wet!). Plants typically need to be watered every 5 - 7 days but growing conditions and temperatures affect drying out, therefore, you should modify this rule of thumb according to your own cultural setup.

It is recommended that fertiliser should be used at half the strength instructed on the pack. Paphs. are not greedy, like other orchids such as Cattleyas, Vandas, etc., and it is better to administer a weak feed regularly than to overdo the strength and only feed occasionally. “Weakly, weekly” is the thing to remember.

After 3 or 4 feeds, a flush with clear water should be introduced to leach out any possible buildup of salts in the compost.

POTTING

As most Paphiopedilum are terrestrial they need a potting medium that will drain well but still retain some humidity around the roots. Too much water retention will suffocate and drown them. Large plants will take a coarser grade than seedlings but the ratio of the mix is the same for all - i.e., 4 parts bark to 1 part perlite. Some growers also add charcoal to the mix to keep it sweet, but this is not strictly necessary.

Repot your Paphs. before the mix has broken down completely, and before the plant grows too large for its current pot. Very large plants would also need repotting when they are divided. An annual repot is advised, orcertainly every eighteen months. This procedure entails first removing any dead roots, then positioning the plant in a new container with its crown level with the rim of the pot, and finally filling in around the roots with compost until the level reaches a little above the base of the plant. Do not bury the new season’s growth as this will cause it to rot. The base of each growth, or “fan”, should be in contact with the growing medium to encourage new shoots to form.

Recently repotted plants should afterwards be placed in a shady area and eventually moved back to normal conditions once they have settled. Restrict watering to a minimum until new roots are apparent, but be sure to maintain good levels of humidity and air movement to assist the plant through what is virtually a stressful period, until it has become established.

And above all, enjoy your Paphs.!

article by PAUL PHILIPS from RATCLIFF ORCHIDS LTD.

Click on to link: www.ratcliffeorchids.co.uk.

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  Phalaenopsis

Phalaenopsis Culture

It is very important to understand in what climatic conditions Phalaenopsis will thrive best so that we can create similar ones as close to their natural habitat as possible. They are warm growing plants and therefore heating is required at a minimum temperature of 65° F. and maximum up to 80°F. This means that in summer ventilation of some sort may be necessary, such as an extractor fan controlled by a thermostat, or roof vents. They like lots of light but not the direct sun . Efficient shading is required in summer time, may be up to 70%. On the other hand in winter or when the light drops below 1500 candles , especially if you are growing seedlings, halogen lights will compensate the light and speed up the growth, which will make a great difference. Next we have to consider air circulation by using electric fans. This air movement is just as important in culture as anything else. The last thing to take into consideration is the humidity. The plants require a humidity between 70% and 80%. To obtain that we need some sort of floor watering such as an under bench water sprinkler and some sort of fogging device for the larger greenhouse. Both of these can be automated by connecting through a humidistat. An example of a fogging system which could be improvised is by using a car wash high pressure water pump and reducing the outlet to an 8 mm copper tube onto which you can connect a few very fine nozzles. You can then mount this high up in the greenhouse and it will produce reasonable fog. To control it, you connect it through the humidistat control and time switch and of course the water intake is from a rain water tub or tap if your tap water is suitable. See diagram below.

And the resolt fog and the humidity about 80%

Now that we have created ideal growing conditions, let’s concentrate on the plants. As Phaleonopsis plants do not have pseudobulbs, the strength of the plants is in their leaves and fleshy roots. The leaves are leathery and large. It is important that you have both of these things in mind when you are dealing with the culture. The compost should be evenly moist at all times, not soggy wet or dry; both of these will kill the root system. That means the compost we choose must have good drainage and at the same time retain moisture. I prefer to use medium bark mixed with moss, and a little bit of perlite (approx. ratio 8 to 1 to ½ perlite). Make sure that the pots are not flat on the bottom, otherwise as soon as you put them onto a flat bench the drainage will stop, and it would be even better if they had additional holes on the side.

The next important factor is the quality of the water you use. Tap water varies from area to area. For example, my tap water is very hard and measures about 550ms using a conductivity meter. So using rain water or reveres osmosis water is a much better choice. Remember that the water temperature should be the same as the greenhouse temperature, and also you may need to water twice or even three times to start with to keep the compost wet. And water only when necessary. You can judge if a plant needs watering by lifting the pot and it will be very light if it is too dry.

To feed the plants, use a well balanced fertilizer such as Peters 20-20-20 at about 300ms or 150 ppm., using a conductivity meter to measure the amount (approx. ¼ tea spoon per gallon of water) or Dyna-gro Liquid Grow (7-9-5) at ¼ tsp per gallon of water. Every 4th watering rinse the compost well with clean water by watering several times . This is to reduce any excessive salt accumulated in the compost. Measure the last drop of water from the bottom of the pot using a conductivity meter. The reading could be very high. Too much salt kills the roots.

RO water or rainwater is about PH 7.1, but after adding fertilizer to it, it drops to below PH 6.5. Phalaenopsis absorb most of the trace elements between PH 5.5 and PH 6.5. If you wish, you can adjust the PH.

I suggest watering the plants early in the day so that the leaves are dry by the evening. And don’t leave any water in the crown, otherwise it will rot. You may on a sunny day foliage feed using seaweed extract fertilizer. It may be also helpful to feed with Epsom salts once or twice a year.

If you keep water in the tank too long and it becomes stagnant, it is more likely to develop bacteria known as psudonomea cattley . This will rot the leaves . You can use a pinch of permanganate of potash in the tank, which will kill the bacteria. It is also useful to spray systemic bactericide / fungicide such as Dithane, Physan 20 or Kocide 101 once a month to cope with the threat or danger of rot especially in the winter time.

Keep the plants clean from insects and pest (scale and mealy bug) by using Provado spray or brush them with methylated spirit or any other good products. Slugs are controlled best by using slug spray or pellets.

Another very distractive insect on Phaleonopsis is False spider mite, known as Tenuipalpus pacificus or Phaleonopsis mite. With their needle- sharp mouthparts, they puncture the epidermis of under leaf of Phaleonopsis and suck out the juices. this causes the leaves to go yellow and the turn brown and fall off.

If detected in time False spider mite can be easily controlled with Provado sprey.

It is good practice to re-pot at least once a year or every 18 months with fresh compost.

If you follow these simple rules you are most likely to enjoy a good crop of flowers. They are some of the most rewarding orchids to grow.

To sum up, Phalaenopsis grow throughout the year with little or no rest, but they grow faster in brighter and warmer conditions

C. Kovac

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  Pleurothallids

The Subtribe Pleurothallidinae contains 20+ Genera, so any recommendation of cultural conditions must be a generalisation, and conditions for a particular species should always be checked in the literature, if this information is available.

However, most pleurothallids grow as epiphytes in cloud forest, in cool, airy conditions at a high altitude. This gives us indications of the conditions we should be trying to reproduce in our greenhouses.

Thus, most plants require a minimum night temperature during the winter months of 10°C (50°F). This should rise during the daytime by about 4°C (7°F). During the summer, the night temperature will naturally be higher, but the daytime temperature should be kept below 30°C (87°F). Even this is too high for some species such as Dracula which should be kept below 26°C (80°F) or desiccation of the plant and flower spikes will occur. These plants also require a higher minimum winter night temperature of 13˚C (55˚F).

The plants should be kept well shaded from direct sunlight from as early as March until October, and certainly heavily shaded during the summer. This in turn will help keep the temperature down.

Most plants require a moist, humid atmosphere. For some, it is not sufficient to 'damp-down' the greenhouse floor, and the use of a humidifier to maintain a relative humidity of at least 70% is recommended. Plants growing in cool, dark cloud forest, where cloud surrounds the plants night and morning, would require a humidity of 90% at these times.

The plants are often found at sites exposed to the wind, so fans are another essential to keep the moist air moving and fresh. Air circulation also helps to minimise fungal growths which can be a problem in the damp conditions.

The plants need to be in a compost which retains moisture but is also free draining. A mixture of fine fir bark, Perlite and dried Sphagnum moss (3:1:1) can be used. This medium should be kept moist by watering with rainwater when required. Rockwool based media can be too wet and cause rotting of the plants.

A general fertiliser should be applied for three waterings, then washed through with plain water to flush out any remaining salts. The concentration should be about 300 μSiemens - i.e. not too concentrated.

Many pleurothallids flower successively on each flower spike so it is important to be sure that this is dead before cutting it off. Some spikes emerge from the plant in a horizontal direction, some even growing downwards through the compost, and these plants should be planted in wire-mesh baskets. The plants should be repotted each year, either in spring or autumn and this opportunity to inspect plant growth carefully should be taken.

The pleurothallids are a varied and fascinating group of orchids to grow and to enjoy.

Eilleen Watson

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Thunia

Thunia are very similar in culture to Calanthe. The canes are very tall 2-4' at times. Therefore staking early is important. The large bell shape flowers will appear about end of June beginning of July and last a long time.

They can be grown in a intermediate temperature with lots of light. During the growing season from early spring to late autumn water and feed well at about 700 ųS of balanced fertilizer.

At about late October they lose their leaves stop watering, keep them dry and cool, that is their resting period. At about February time repot in fresh mix I use peat-based compost mixed with perlite to keep it open. New canes will start on the base of the old ones When you see that start watering and feeding. The old canes will eventually become soft and will start new shoots on the side. If you don't want any more plants remove them.

C.Kovac

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Pleiones

Pleiones are quite easy to grow in spite of the fact that they are orchids, and most people assume that they need a lot of heat in the winter. In fact the reverse is true, as they need cold for most of the winter. They are only in active growth in spring and summer.

In the wild they are found growing in moss or soil on steeper slopes or cliff faces in the foothills of the Asian Mountain ranges such as the Himalayas, so they are used to standing some degree of frost. Many people successfully grow them outdoors in the UK, only protecting them from the excessive wet and cold by covering them with a glass sheet or straw for example. They enjoy a well drained compost and suitable ones can be made from various mixtures of the following; Orchid bark / leaf mould / sphagnum moss / perlite. The one we use is 10 parts by volume of medium grade Orchid bark, plus 1 part of coarse perlite, 3 parts of leaf mould, and 2 parts of sphagnum moss. You may also use some charcoal but it is not essential. Pleiones need repotting every year.

The following notes will now describe the typical year in the life of a Pleione.

JANUARY. Bulbs are still in a dormant state and the first thing to do is to prepare them for repotting. I prefer to leave the bulbs in their old compost until early January to prevent the premature shrinkage by dehydration so they remain undisturbed and cold. Start by carefully lifting the bulbs from the old compost and shake off the excess. Break up the group of bulbs and bulbils. You will be left with the old roots and the remnants of the previous years shrunken (back) bulbs, both of which have to be removed. Trim back to within ½ inch of the bulb base taking care not to damage the new embryonic growth buds which lie on the underside of the bulb but generally outside the roots. (Usually 2 to 3 new buds are visible). Also remove any surface vegetation. The bulb is now ready for repotting. Using shallow pan type pots, loosely fill to within an inch of the top and plant the bulbs some ¾ of their depth, firming around them. In a standard 140 mm diameter 90 mm deep pot place 5 or 6 bulbs around the edge and 1 in the middle . Alternatively pot them up singly, but a group display is more spectacular. Spray with a little rain water and leave to grow in good light and a gentle heat. Plant up the bulbils (small bulbs) in separate pots or trays.

FEBRUARY / MARCH. In about six weeks you will see flower shoots appearing. Continue to spray with rain water every week or so until the flowers have come and gone. Do not soak the compost with water until the bulbs are in full growth otherwise you will kill the roots and the plants will not recover. From the beginning of March it will be necessary to reduce the light levels by either shading or placing the pots in a shady area to prevent leaf scorching.

APRIL. Plants are now in full growth and the leaves should be around 4” long and the flower stems will have died back. These can be removed by the hand by gently pulling the old stems out. Continue to water sparingly but increase this amount as the leaves grow, until eventually you can water generously.

MAY. Start feeding the plants based on using a balanced fertilizer but apply at ½ strength stated on the label. Feed at alternative watering and continue to feed until the middle of August and then switch to high potash feed until the end of September. During the hot summer months it is better to place the pots outside in a shady position,, for the plants prefer not to be subjected to very high temperatures, they like to be grown in temperates of around 50- 75 F.

JUNE / JULY / AUGUST. Keep pots outside in the shade and continue to water and feed as stated above. During this time the leaves will grow to perhaps 12-15” in length and you should see several new bulbs growing from the old bulbs; on average you should see 2-3 new bulbs from the old bulbs in a full season. Keep an eye out for pest which are few but spray with a weak solution of soap or recommended pesticide such as malathion.. Regular overhead sprays of water will be beneficial on summer evenings in addition to the normal watering.

SEPTEMBER. At the end of September or before the first frost , bring the pots inside a cold greenhouse or cold room. gradually reduce the watering and feeding.

OCTOBER. Stop watering around the middle of October. Allow the pots to dry out and protect from frost as a precaution. After a couple of weeks the foliage will start to go brown and die back. Eventually the leaves will either drop or can be removed easily to give bare bulbs.

NOVEMBER / DECEMBER. Continue to clear away the dead leaves but other then this do nothing to the bulbs until it is once again time to repot in January.

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Vandas

Vibrant, Voluptuous Vandas - v.v.vvrooom.......and what's more, they come in blue, too

Some thoughts on growing Vandas and their close relatives: Vandas are voracious, greedy plants - they demand lots of everything.

Lots of heat - I grow at a minimum of 60F throughout the night but I am sure that another 5 degrees, and preferably 10 would be greatly appreciated by them. But who can afford this luxury throughout the winter months? However, much below this level and there is a noticeable shortening of their root tips and formation of less smooth roots. (N.B. close V. coerulea derivatives prefer it a little cooler.)

Lots of light - hang them up as close to the roof as possible (it's warmer there too) but make sure you have some degree of shading from the early summer sun . During winter months I boost the late afternoon light and early evening by a 300 watt floodlight.

Lots of humidity - they seem to love regular automatic spraying at ground level. Normal tap water is sufficient for this but higher up I also lightly mist the atmosphere generally once a day or whenever I enter the glasshouse, preferably using rainwater.

Lots of water - again preferably rainwater but it is difficult to achieve enough pressure to reach the roof space, so again, I use a tap water hose but it is essential that they receive sufficient watering until their roots pass the mottled wet appearance and turn a dark green in colour showing that they are thoroughly saturated .

Lots of fertiliser -at least half strength once a week all over them after receiving the drenching above when the vellum is able to hold the moisture (not a bad time for a weekly addition of a little 'Superthrive' although not too much or abnormal thickness of roots seems to occur).

Lots of air movement - I have two 12 inch house fans, one at either end, one high, one low, going 24 hours per day to stir up the atmosphere and to dry out the leaf axles.

Lots of height - grown well, it doesn't take many years for some vandas to exceed eight foot or so from leaf axle to root tip so you really need to think about this when deciding the positioning and height of the greenhouse.

And finally, Lots of love - how could you fail to have this when you see the results of the above treatment? And what's more, this part costs nothing.

Stephen J. Taylor

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(c) Copyright 1998 C.KOVAC