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November 2015 Magazine

The Wessex Orchid Society

www.wessexorchidsociety.org.uk

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From the Editor.

For our Christmas lunch next month we are trying out a new venue,Chilworth Manor Hotel, near Southampton, SO16 7PT. If you arecoming you should aim to arrive at 12 for 12.30. A map giving roughdirections is enclosed with the magazine for those that are attendingthe lunch. If you have not yet signed up for the Christmas lunch andwould like to come, please see the Treasurer if you are at theNovember meeting, or ring Sue Sapsard (Tel 02380 292046) if youare not at the meeting, to book a place. In both cases you will need togive your choices from the Christmas lunch menu (both the Treasurerand Sue have details). Chilworth Manor want details of numbersfinalised as soon as possible and so the deadline for signing up is Nov19th.

I am grateful to Steve Crabtree, who has taken some excellent photosof our Autumn show. These provide the main part of our show reportin this magazine, together with a list later in the magazine of thoseorchids that won trophies or were commended for cultural growth. Wehave a couple of articles by Ron Lamont, the first with six top tips forwinter and the second on “Winter warmth” in greenhouses. We alsohave another in the series by Derek Ridley on projects to do in a day. Ihave added an article by Sue Bottom from the American OrchidSociety magazine “Orchids”. This contains some useful information onwhy orchids need a drop in night-time temperature.

Please note that next year we have a distinguished and entertainingspeaker Thomas Mirendra (curator of Orchids at the SmithsonianInstitute in America) speaking on Orchid Pollination at our Aprilmeeting on April 9th 2016. It promises to be a good talk and so do putthe date in your diary, and invite friends too! The Orchid Show inLondon is earlier this year and so we will be running a coach trip there on 1st April as an extra.

Jonathan Watson

Six Top Tips for the Winter

Top Tip 1 – To give your plants the same winter daylength as theywould see in their country of origin; just set a timer to turn lightson at 6am in your greenhouse.

The day shortening in the tropics is about half what it is here, soeliminating the morning half of our shortening will make them feelmore at home. It won’t hurt for the lights to stay on after daybreak, sofor convenience I set them to stay on until 9:30am all winter. Research says most orchids are not “day length” plants, but I reckon the extralight helps if only because they are “awake” and working for longer. Top Tip 2 – To feed your plants while they are shut in for thewinter, be sure to light a tea-light for them every morning. A plant, apart from water and its derivatives, is almost all carbon. Thiscarbon comes from CO2 in the air, and in a closed environment is soonused up. In the home, people produce lots of CO2, especially if theycook with gas, so no need for supplementation there, but you need it ina greenhouse unless you happen to live there!! Prince Charles wasfamous for saying that plants grew better if you spoke to them, and hewas right – just by being there and breathing out, you give them a jollygood feed.

Top Tip 3 – To keep the air fresh and stop your plants drying outtoo fast with artificial heat, have a big water feature in your wintergreenhouse and turn it on between 10am and 3pm. It’s best if water falls from a height and produces a certain amount ofspray. Be sure to use only rain water, or your plants will quicklyacquire a tenacious bloom from stuff dissolved in tap water. In mylittle house, the floor is all pond with stepping stones, and pumpedwater falls from a hose at a metre’s height.

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Top Tip 4 – To avoid sun scorch and “frying” drying in thewinter once the shading is off, rig up a “sun switch” to turn onhumidifiers when the sun comes out. You may need some help with the electrics, but it’s worth it. Eventhe smallest house will need two regular domestic humidifiers set atmax, which creates a lovely cloud forest environment. A regularcentral heating room thermostat in a sunny place works fine, but thewiring needs to be changed round so it comes on, not off, with risingtemperature. Topping up will usually need doing every morning; rainwater is essential to prevent your plants acquiring a tap water bloomor “snow”.

Top Tip 5 – Insulate, insulate, insulate! Winter ventilation isunnecessary. Although there is nothing like a good “airing” on a bright warmsunny quiet winter’s day, it’s best to keep the hatches on the rest ofthe time. Provided you supplement with CO2, ventilation serves onlyto bring in moulds, rots and pests, and to waste your preciouswarmth. I insulate all north-facing parts with one-inch polystyrenefoam, and the rest with an additional layer of twin-wallpolycarbonate. I find this enough to prevent “drip-drip” condensationand to keep my average power use for heating to around 200W (lessthan £5 a week) for an admittedly very small greenhouse.

Top Tip 6 – Circulate, circulate, circulate! Fans are the cheapest weapons in your armoury. Air movement helps avoid wet and soggy conditions, and keeps rotsand moulds at bay. It also stops all your heat rising uselessly to theroof and stops pools of cold air collecting near the ground. Fans costalmost nothing to run. Be sure to point fans somewhat up or down tocombat stratification, and don’t point them directly at plants, to avoidexcessive chilling and drying.

Ron Lamont

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Why Orchids Need a Drop in Nighttime Temperature.

Have you ever wondered why all the books say that many orchidsneed a 10 to 20 F (about 5.5-11 C) drop in temperature from day tonight? Lower nighttime temperatures are critical for good growth andflowering because there must be a proper balance betweenphotosynthesis and respiration for a plant to grow and bloom well.

ORCHIDS BY DAY. During the day, your plants are busy:Making Food. Your plants are busy using solar energy in a processcalled photosynthesis. Light is absorbed by the chlorophyll in theleaves and the carbon dioxide absorbed by the plant is converted intochemical energy in the form of sugars and starches. Using Food. Your plants consume their energy reserves in a processknown as respiration. The food reserves of sugars and starches areused to maintain existing tissue as well as produce new growths,flowers and seeds.

ORCHIDS BY NIGHT. At night, photosynthesis stops but growth andrespiration continue drawing on the energy reserves created during theday. Respiration occurs more quickly at higher temperatures than atlower temperatures. At lower temperatures, it is possible for the energyconsumption to be less than energy production, allowing the plant tostore energy for future use, including flowering. If night temperaturesare too high, food is used faster than it can be made so growth is poorand orchids either do not flower or they flower poorly.

PROVIDING LOWER NIGHTTIME TEMPERATURES. Providingcooler nighttime temperatures can be problematic if you're growingindoors in a climate-controlled environment. Perhaps the bestalternative is a programmable thermostat or manually turning thethermostat down at night. Orchids growing by a bright window will bea few degrees warmer during the day from solar gain and orchidsgrowing by an open window may be a few degrees cooler at night inwinter. You can provide lower nighttime temperatures if you growyour orchids outdoors or on a screened porch during the warm season.

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FLOWER INDUCTION BY NIGHTTIME CHILLING. Many orchids require a significant day—night temperature differenceto induce flowering. Phalaenopsis require a" 15 F (8.3 C) drop innighttime temperature for two or three weeks to initiate their flowerspikes. Cymbidiums and dendrobiums can require an even largertemperature difference. Zygopetalums crave cooler nights. I havelong loved zygopetalums with their bluish purple, green and bronzeflowers and incredible fragrance, although they have tended to bevery short-lived in my care. I've tried growing them in a wide varietyof light conditions and potting mixes. Knowing that they like coolerconditions than we have, I tried the old grower's trick of growingthem in sphagnum moss in a clay pot dropped in a second clay pot tokeep them a little cooler from the water evaporating from the porousclay. They grew better, but still struggled. I was telling Fred Clarke ofSunset Valley Orchids my tale of woe and he told me to get them outof the greenhouse and under the shade of a tree. That provided a fewextra degrees of nighttime cooling and the growth rate exploded overthe summer. I was treated to more zygo blooms than ever before.

Understanding your plant's metabolism gives you insight into howbest to grow it. Cooler nighttime temperatures allow your orchid tostore, rather than consume, the food it manufactured during the day.This stored energy can then be used by the plant to produce flowers.Next to insufficient light, insufficient day to night temperature changeis the most likely cause of your orchid failing to bloom. If your plantsare growing well and you are sure they are getting enough of the rightkind of light, try dropping your night temperatures by a few degrees.You may be pleasantly surprised by the increase in flowers yourplants produce.

Article by Sue Bottom in the AOS magazine Orchids, Nov 2015

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W.O.S. Autumn Show. Photos by Steve Crabtree. The Show results are listed later in the magazine, together with photosof the awards being made to Tony Nappin, for best species and best inShow, and John Dennis, for best hybrid, by the Mayor of Fareham.Below are some of the photos taken by Steve Crabtree of orchids onour display.

Left: Galeandra bauerigrown by John Dennis

Below: close-up ofCoelogyne barbata, thebest in show, grown byTony Nappin.

Below: Encyclia cochleata

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Three of the Phragmipediums on displayshowing the different shapes and hues of redproduced by crossing Phrag besseae withother Phragmipedium species

Colmanara CatantePacific Sun Spots

grown byJonathan Watson

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Four of the Cattleyas on display, grown by Brian Gould and Jonathan Watson

Aerangis brachycarpa

grown by Ann Thaventhiran Unusual Phalaenopsiswith peloric markings

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Winter Warmth – Don’t lose your plants to Jack Frost!!. The time has come to dust off our heaters and give them a trial runon a nice day to burn off the dust on the heating elements and letthe fumes blow away through open doors and windows. While we’re about it, it’s a good idea to remind ourselves what weare trying to achieve with our heating systems, and maybe carry outsome improvements before the worst of the winter sets in. Ourplants are very sensitive to temperature, and many use the coldnights to trigger blooming; so although we primarily want to stop it getting so cold at night that it damages plants, we should also wantthe cool of the night to be a nice stable temperature to avoidupsetting their rhythms. This means that our heating system shouldideally provide a constant stream of just enough heat to counter theoutside cold. A feast and a famine may keep the wolf from the door,but the peaks may dry plants excessively and upset theirmetabolism. We also, of course, want to achieve this goal aseconomically and reliably as we can.

Phalaenopsis hybrid grown by Ann Thaventhiran

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A common fault is to have the thermostat too far from the heater,with the result that the heater stays on for long periods and parts ofthe house suffer excessive temperatures. All thermostats have whatis called a “dead band”, meaning that the temperature they cut in atis some degrees different to the temperature they cut out at, sohouse temperature will swing up and down throughout the night asthe thermostat switches on and off – hardly what we want

Thermostats are actually deliberately designed to have quite widedead bands, typically 5º to 10ºC (10º to 20ºF). This is to stop thedevice switching very rapidly and wearing itself out – a thermostatwith no dead band will “chatter” and buzz through a lack of positivecontact, and soon destroy itself. However, with a little care, we canarrange for a thermostat to switch reasonably frequently, to giverelatively small “puffs” of heat which will soon even themselves outinto a stable constant temperature. This technique is known as“short-cycling”, and is also the way that thermostats should be setup in tropical fish tanks.

To use this technique, the thermostat is placed where it can “see”the heater, so that it soon switches off before the heat build-upbecomes excessive; it will then stay off while the heat “puff”spreads itself out around the house, giving an even and constantnight temperature. This temperature will be the one at which thethermostat comes on, and if it is done well, the variation through thenight in the main part of the house will be only 1ºC or less. Personally, I use a multi-layered approach to heating. I have abasic heater (in my case a waterproof tube heater) which runs allnight on a timer, and is enough on its own in the milder weather,supplemented when it gets really cold by a fan heater arranged to“short-cycle”. This not only gives very stable temperatures but also

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provides some redundancy – should either heater fail, there is alwaysthe other one to save the day.

Whilst on the subject of heat system reliability, a word of warning.For safety reasons, the system should always be fed through an RCD.However, there are two types of these, called passive or latching andactive or non-latching. Sadly many suppliers get these terms mixedup or simply don’t know. The passive type comes on again after apower break, the active type doesn’t, and unfortunately nearly all theones on the market are the wrong ones – those that stay off after amomentary power cut and let your plants freeze for the rest of thenight unless you are awake enough to go and reset the RCD. PassiveRCDs should be used with heating and refrigeration systems, andactive ones with garden tools and power tools. Passive RCDs arehard to find, and actives get palmed off as passives – always buy on asale or return basis and try them out on something like an electrickettle – plug in, set the RCD, and make sure the kettle’s light comeson; then switch off at the wall for a moment and switch on again – ifthe kettle is not then working, the RCD is not the type you need.

Try RCD Re-wirable plug 13A white Passive/Latching at Astra247.com.

Correct sizing of heaters is essential for best operation. I have a tinyhouse, and my heaters are likewise tiny. The tube heater is 200W andthe fan heater is adapted to be 200W, as low wattage fan heaters aremore or less non-existent. If you are obliged to use heaters that arebigger than ideal, be sure to aim them at the floor so that the heatspreads out well, and be very sure to short-cycle them. If you areusing a fan heater’s own thermostat for control, be very sure toachieve short-cycling by directing some of its airflow back to itsintake side – you can use rigid plastic sheets to do this, maybe morethan one.

Be sure to insulate well, and good luck with your winter warming! by Ron Lamont

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WOS Autumn Show 2015 results

Best Species: Coelogyne barbata grown by Tony Nappin Best hybrid: Masdevallia Confetti grown by John Dennis Best in Show: Coelogyne barbata grown by Tony Nappin

Orchids of cultural excellence:

Epidendrum delicatum grown by Grahame Coleman Rossioglossum Grande hybrid Grown by Brian Gould Cymbidium hybrid grown by Brian Gould Phragmipedium Eric Young grown by Alan Sapsard Phragmipedium hybrid grown by Margaret Hart Miltonia Honolulu “Warne’s Best” grown by Jonathan Watson Phalaenopsis hybrid grown by Alan Sapsard Aerangis brachycarpa grown by Anne Thaventhiran

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Our Society programme for the next few months

12th Dec Christmas lunch at Chilworth Manor Hotel, SO16 7PT

9 Jan 2016 Orchid hunting trips to Northern Cyprus, Ecuador

& .commercial Dutch Nurseries. Lady Samantha Hurley

13 Feb 2016 Plant Clinic and member’s plant sales.

5 March 2016 WOS Annual Spring Show, Portchester

9th April 2016 Orchid Pollination. Thomas Mirenda.

2015 Show Dates for your diary

Sat 5th March 2016 WOS Spring Show, Portchester Community School

Friday 1st April 2016 Society trip to RHS Orchid Show, London

Friday 17th June-Sun 19th June. Malvern International Orchid Show

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Cover: Rossioglossum Grande cross grown by Ron Lamont

Above: Best in Show and best species: Coelogyne barbata grown

by Tony Nappin Below: Best hybrid: Masdevallia Confetti grown by John Dennis