Handy Tips for Orchid Growers

Common names for Orchids
Flowering Times for Popular Orchids
Orchid Shapes
Botanical Language
Growing Tips
Seed Pod Maturation Times
Reducing Water Usage
Introducing the PAR Meter
Virus testing

Common Names for Orchids

Common name Botanical name
Generally only includes orchids grown in Canberra
Beak orchid Lypantherus (genera)
Bearded orchid Calochilus (genera)
Beech orchid Dendrobium falcorostum
Blue orchid Dendrobium victoriae-reginae
Bottlebrush orchid Dendrobium smillieae
Brown Beaks Lypantherus suaveolens
Butterfly orchid Oncidium papilio
Christmas orchid Calanthe triplicata
Chinese Ground Orchid Bletilla striata
Cooktown orchid Dendrobium bigibbum
Crucifix orchid Epidendrum radicans
Cucumber orchid, Gherkin orchid Dockrillia cucumerina (syn. Den. cucumerinum)
Dancing Lady orchid Oncidium (genera)
Dagger orchid Dockrillia pugioniformis (syn. Den. pugioniforme)
Donkey orchid Diuris (genera)
Duck orchid Caleana (genera)
Golden Arch orchid Dendrobium chrysotoxum
Hyacinth orchid Dipodium punctatum
Ironbark orchid Tropilis aemula (syn Dendrobium aemulum)
King orchid Thelychiton speciosa (syn. Den. speciosum)
Lady's Slipper orchid Paphiopedilum (genera)
Moth orchid Phalaenopsis (genera)
Greenhoods Pterostylis (genera)
Nodding Greenhood Pterostylis nutans
Blunt Greenhood Pterostylis curta
Maroonhood Pterostylis pedunculata
Harlequin orchid Sarcochilus hirticalcar
Orange Blossum orchid Sarcochilus falcatus
Onion orchid, Tea Tree orchid Dendrobium canaliculatum
Pansy orchids Miltoniopsis (genera)
Pencil orchid, Bridal veil orchid,
Rats tail orchid, clematis orchid
Dockrillia teretifolia (syn. Den. teretifolium)
Pink Rock Orchid Thelychiton kingianus (syn. Den. kingianum)
Ravine Orchid Sarcochilus fitzgeraldii)
Spider orchid Brassia (genera)
Sun orchid Thelmitra (genera)
Swamp orchid Phais tankervilliae
Tongue orchid Dockrillia linguiformis (syn. Den. linguiforme)
Wax Lips Glossodia (genera)

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Flowering Times for Popular Orchids

Orchid J F M A M J J A S O N D

Flowering times approx for Canberra, may vary in other regions

Cymbidium hybrid - - - x x x x x x - - -
Thelychiton speciosa - - - - - - - x x x - -
Bletilla striata - - - - - - - - - x x x
Coelogyne cristata - - - - - - - x x x - -
Pterostylis species - - - - - - - x x x - -
Laelia anceps - - - - - - - - x x - -
Dockrillia linguiformis - - - - - - - - x x - -

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Orchid Shapes

In order to describe accurately the features of a particular plant, botanists have developed a generally accepted set of terms and criteria. There are descriptions covering characteristics of all parts of plants, such as leaf shape, shape of stem/bulbs, covering and colour of leaves, flowers, etc.

The main contributors to the terminology were C. Linneas, especially his Philosophia botanica (1751) and J. Lindley almost a century later. An excellent presentation of botanical terms, descriptions and the botanical language is provided in William T. Stearn Botanical Latin Timberpress paperback edition 2004. The following draws on some of that material as used in describing orchids.

Inflorescence Shapes

Orchid flowers show incredible variety in the shape of the individual flowers and the arrangement of those flowers. The following diagram illustrates the major forms of the flower arrangements. Examples are given of the orchids that have those particular forms.

Pseudobulb Shapes

A distinguishing feature of orchids is the variety of shapes of the pseudobulbs. Some common shapes are shown below, along with typical cross sections. It should be noted that that all orchids have pseudobulbs. Some pseudobulbs may be naturally ribbed, whereas in others the presence of ribbing indicates moisture stress.

Leaf Shapes

Again, there is a wide range of shapes in orchid leaves. Many of the common shapes are illustrated below, including several illustrative cross sections.

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Botanical Lingo

The internationally accepted language for naming and describing plants is latin. Many latin words, or something very close, have been accepted into the English language so it is often possible to interpret botanical names without any knowledge of latin. The following table provides examples of some latin words used in describing orchids that are frequently encountered.

Latin(English) Meaning
Source: Stearn, William T. (2004) Botanical Latin

Clavatus (Club shaped)

gradually thickening upwards from a very tapering base

Cochlearis (Cochlear)

when one piece, being larger than the others, and hollowed like a helmet or bowl, covers the others

Resupinatus (Resupinate)

inverted in position by a twisting of the stalk. Typically refers to the flowers - Encyclia flowers are non-resupinate as the lip is at the top.

Nutans (Nodding)

inclining very much from the perpendicular, so that the apex is directed downwards

Sessilis (Sessile)

sitting close upon the body that supports it, without any sensible stalk

Fusiform (Spindle shaped)

thick, tapering to each end

Canaliculatus (Channelled)

long and concave, so as to resemble a gutter or channel

Teres (Terete)

the opposite of angular

Filiformis (Thread shaped)

slender, like a thread

Linearis (Linear)

narrow, short, with the two opposite margins parallel

Cucullatis (Hooded)

a plane body, the apex or sides of which are curved inwards, so as to resemble the point of a slipper, or a hood

Fimbriatus (Fringed)

having the margin bordered by long filiform processes thicker than hairs

Giganteus (Gigantic)

tall, but stout and well proportioned

Dorsalis (Dorsal)

fixed upon the back of anything

Lateralis (Lateral)

fixed near or upon the side of anything

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Growing Tips

Pot Stand

A simple and cheap pot stand can be made using plastic pots. Select a pot which is at least several sizes larger than the one in which the orchid is growing, invert it and cut a cirular hole in the bottom big enough to hold the pot with the plant but not allowing it to fall through. Alternatively, if the pot to be used as the stand is only one size larger, (eg 250mm to hold a 200mm ) it may be necessary to cut about 10mm off the bottom of the pot. In this case ensure the cut edge fits into the lip of the plant pot in order to restrengthen the holding pot.

The following diagram illustrates.

This approach has various advantages over the usual double potting method:

A word of advice: When cold, a plastic pot is stiff and brittle, making cutting difficult and possibly dangerous. Therefore place the plastic pot in full sun on a warm/hot day for at least 15 minutes before attempting to cut it. The plastic will become fexible and easier to cut. A "stanley knife" is adequate to cut the pot, BUT BE CAREFUL as flesh is softer than plastic.

Watch those Roots

Ever wonder how well a recently potted keiki, seedling or division is rooting? This simple approach to potting allows you to see without pulling the plant and medium out of its pot.

Plant the orchid in a clear plastic drinking "glass" (270ml sparkling tumblers are quite suitable) after cutting some drainage holes in the bottom. Now slip the plastic tumbler into a suitable sized plastic pot (a snug fit is best). Then at any time you can observe the progress of the orchids roots by simply lifting the plastic tumbler out of the pot. This method will also help provide some insulation for the orchid's roots. Unaware of the origin of this suggestion, but it is used by Brian and Lynne Phelan.

The following images illustrate. The second image suggests that the Thelychiton kingianus keiki has made good root growth.

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Hang 'em High

Various orchids grow best in a hanging basket. The following illustrates a simple and cheap method of constructing a hanging basket.

All you require is a wire coat hanger, the usual plastic pot, a pair of pliers or wire cutters and a drill or stanley knife. The best coat hangers are the galvanised (not painted or plastic coated). These are tightly wound at the neck and will not fall apart.

The following diagram illustrates.

Simply cut the bottom of the hanger, straighten the arms and then bend the bottom 1 or 2 cms of the ends at right angles. Make two suitable holes diagonally opposite in the top of the rim of the pot (be careful if using a knife), then insert the ends of the hanger into these holes.

This tip was provided by Bob (the Builder) Bush

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Seed Pod Maturation Times

Ever see a seed pod on an orchid or pollinate an orchid to produce seed? The challenge is then to determine when the seed pod is ripe to harvest if you want to raise seedlings (or rather, forward to someone who has expertise and a proven track record in flasking). The following website will help.

http://members.iinet.net.au/~barryg/Orchid_Seed.htm

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Reducing Water Usage

There are various ways that we can reduce the quantity of water needed to keep our orchids alive and healthy. In the Canberra region the low humidity in summer and current water restrictions means we must strive to get the greatest benefit from each drop of water.

The following are a few ideas that you may wish to consider, especially for use in the warmer weather. You may already be using these ideas while some may not be suitable or practical depending on your circumstances. Also be aware that changing your current practices may raise new problems and challenges.

1. Use mixes that are more water absorbent/retentive so you donít have to water as often or as long.

Especially effective in this regard is coarse coir (coconut). Coarse coir is easily wetted and allows good air circulation. While the fine particled coir peat is good at holding water, on its own it is generally too dense to allow adequate air movement around the orchid roots resulting in rotting of the roots. A mix that is quite suitable is perlite and peat moss (about 8 parts perlite, 1 part peat moss). Some growers have added water crystals to bark based mixes, but this is not popular. If using the coarse coir take note whether it includes fertiliser and adjust your fertiliser program accordingly. Also the coarse coir includes a lot of fine material - consider screening out this material for certain orchid types such as angraecums.

If you have orchids in coarse bark, consider increasing the water holding/wetting of the mix. Try adding some diatomite chunks (these wet well and help to prevent the bark from getting too dry or to rewet bark that has become water-repellent) or sprinkle some dry coco peat over the top of the pot, then tap the side to get it to sink lower into the mix. You might need to modify you watering regime in the cold weather so as not to get the mix too wet.

2. Make alterations to the growing environment to reduce the rate of evaporation (and thus the amount of watering required).

If you have a shadehouse, try enclosing some of it, at least the bottom metre, with agricultural plastic in order to reduce evaporation loss. You can cover the entire house, but then would need to allow adequate ventilation and ideally evaporative cooling as the enclosed air temperature will get to 10C or more higher than the outside air if in full sunlight.

If the lower part of the shadehouse is enclosed, humidity will be higher and temperature lower on the floor of the shadehouse. Some orchids, particularly the terrestrial types such as various sarcochilus will be happy there. However, if the light level on the floor of the shadehouse is very low, some orchid species may grow too rank and flowering will be reduced.

A layer of plastic on the floor of the shade/glass house covered with some porous or water absorbing material will help raise the humidity and lower the temperature. Try using wood shavings, pine chips, scoria, old carpet, or even concrete blocks (especially the hollow ones). Ideally the material should not compact too much, so that some air circulation through the material and release of moisture is possible.

Consider covering your benches with water holding material (eg coco peat on top of shadecloth). This will capture any excess water and help raise the humidity. Orchid roots may however grow through the bottom of the pot into this material.

If you are growing orchids in an unenclosed structure or under trees, place them close together. If watering with a hose, water is more likely to get to the plants and there will be less evaporation loss. Cymbidiums (hybrids) in particular can be placed as close together as the pots will allow until spikes are emerging. Do not put small and large plants too close together as the small plants may be covered and deprived of light or not get sufficient water. Be careful putting plants close together in a glasshouse, as this may accentuate wilt and other disease problems.

3. Get the maximum use from water.

If you have a small number of orchids and have the time, the most efficient method of watering is to dunk 'em. Dunking ensures that the entire potting mix is wetted which may not always happen in other watering methods apart from flooding. The following diagram illustrates one such approach. It is suggested that you have three buckets (used 10 litre paint/glue buckets are fine). Use the first bucket as your source of water and add fertiliser if appropriate. Tip a suitable amount of this mixture into a second bucket into which you will place the potted orchid. Top up the water level so that it will just reach the pseudobulbs. If the pot is very dry, it will initially float so you may need to push the pot into the water. Leave for a suitable time - a couple of minutes if the mix is coir, half an hour or more if mix is coarse bark and it is very dry. Lift the orchid up, wait until water stops flowing freely from the pot (a few seconds) then place in a third bucket in which a squat plastic pot has been inverted, and allow to drain fully. At the same time the process can be started for a second orchid. Water collected in the third bucket can be reused (tip into the second bucket). Check your orchids carefully - it is important that diseased plants not go though the same water as healthy plants.

Dunking is also very effective for orchids which are on mounts or rafts.

If you don't want to dunk, try holding the pot over a bucket and pour water over the pot until sufficiently wet. Retrieve water from the bucket for the next pot.

Capture excess water.

If using a hose, you might consider making a system for capturing any water which drips through or misses the pots. For example plastic sheeting can be fixed under the benches to make troughs. Provide a slope so that water will flow to one end for easy collection. Again, do not reuse any water from diseased plants. Use rafts in preference to mounts. A raft refers to any solid material which is positioned horizontally. This gives greater opportunity for water to be absorbed.

Suggestions provided by Bill Ferris

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Introducing the PAR Meter

Light is important to orchids (and plants generally), being the energy source for photosynthesis and thus plant life. But to use a variation of a popular saying, 'light ain't light'. Besides the quantity, light must be of the right type (or spectrum range) for successful orchid growth and flowering.

All orchids do not require the same amount of light. Some orchids grow best in full sunlight, while others require heavily shaded situations. While these general descriptions are helpful, better quantification of light requirements by orchid type and the ability to measure the amount of light available in our orchid houses would be useful. How often have you observed that by moving an orchid from one position to another in the orchid house makes a big difference to the growth of the orchid. Also, have you ever considered the effect of different covering materials on light transmission?

A useful instrument for measuring the amount of light available which can be utilised by plants is a Photosynthetically Active Radiation (PAR) meter. This measures the amount of light in the wavelength of 400 to 700nm (nano metres = 10-9x1 metre) in falling on a flat (level) surface. It recognises that as the angle of the sun in the sky declines (going into winter) the sunlight is spread over a wider surface area (think of a ray of sunlight as a drinking straw and how the cross-sectional area of the straw increases as it is cut at sharper and sharper angles).

The PAR Meter

The society has invested in a PAR meter which is available for use by all members (contact Jane Wright). An image of the meter is shown below:

The meter consists of two main components:

Operation of the meter involve holding the sensor vertically and pressing and holding the button on the reader until numbers appear on the screen. It is important that the sensor be held vertical while taking a reading.

The meter provides measures in terms of μmoles/sec. For all practical purposes the dimensions of the reading are unimportant. What is important is that the maximum reading you can expect is about 2.4 in full sunlight.

You will find that readings are quite sensitive and it is best to take several readings in exactly the same position as quickly as possible and take an average of those readings (even discard any that are 'way out'). I suggest it is best to take readings when the sky is clear (cloudless) as even small changes in cloud cover have quite an impact on the readings. Readings will obviously vary by time of day, day of the year and of course cloud cover.

Some results

At this stage we are finding our way in the use of the meter. There are many issues requiring further investigation, such as whether an average should be taken over the day (and if so, how frequently should readings be taken), how to handle readings in different seasons and the importance of radiation outside the PAR band (especially ultraviolet radiation).

The following chart provides illustrative readings I have taken to investigate the effect of various orchid house covering materials on light availability. The materials were simply spread over a frame held level and readings taken approximately 6 inches below the material. Readings were taken hourly in mid February over various days in order to get readings under clear sky conditions.

Readings are shown in the chart for full sun, agricultural plastic, glass (3mm), aged polyflute and 50% shade cloth. In general, glass and ag plastic had, as might be expected, the least reduction in the amount of light. I also took several measurements using single layer clear polycarbonate (SUNTUF®) which gave similar readings to glass and ag plastic. I also tried different coloured shadecloth (cream and green) but there was no noticeable difference (guess this might be expected as both were rated at 50%).

A paper on technical aspects of radiation and PAR is being prepared. (Bill Ferris)

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Virus Testing

A simple virus testing kit imported by Easy Orchids is now available from some suppliers. It tests for two of the more common viruses, namely Cymbidium Mosaic Virus (CMV) and Odontoglossum Ringspot Virus (ORV). Given the hassles now associated with having testing done in Tasmania, it provides a relatively cheap (around $10) and easy approach, even though limited to only two virus types.

The test involves taking a small piece of plant tissue (approx 2 cm square), placing it in a plastic bag with 1 ml of extraction buffer (liquid) and crushing the tissue in the buffer solution to produce a green liquid. Three drops of this green liquid are placed on the test aparatus and after three minutes the results can be read.

I applied the test to a suspect cymbidium. Image shows leaf from which a sample was taken.

 Click to view large picture

Another leaf sample is shown here. Necrosis is clearly obvious, a common result of virus.


 Click to view large picture

The test results on the aparatus are shown here. The test on the left is from a clean plant. The results for my suspect orchid are shown on the right and indicates the orchid had both viruses. The positive result for ORV was surprising as the plant did not show the typical circular markings.

 Click to view large picture

In conclusion, the test kits would appear to be useful. However, although the cost is not high, it should be remembered that the test is only for two virus types. Hobby growers may prefer to adopt the approach if in doubt, chuck it out.

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