TITLE>Growing Orchids Under Artificial Light, Carol Allen, 3 Jan 98

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GROWING ORCHIDS UNDER ARTIFICIAL LIGHT

WBS Sat 3 Jan 98


  1. Pre-discussion Mailout

  2. Topic Transcript

  3. Plant Photoperiodism
    by Daniel Mascheck

  4. Transient Light: Does it Affect Growth?
    by Ed Wright


PRE-DISCUSSION MAILOUT

Growing Orchids Under Artificial Light
©Carol Allen

Light is energy.

All living organisms require energy to maintain life. Light is the form of energy that is used by plants. Light is the most important component in the artificial world that we create for them. It is the most important element whether you grow in a greenhouse, or on a windowsill, or under artificial lights.

Plants convert light (radiant energy) into chemical bond energy through a process called photosynthesis. Chemical bond energy can be stored by the plant for later conversion into glucose. Glucose is then utilized on the cellular level to carry out metabolic processes.

There are several light receptive pigments found in a leaf cell. The one we are most familiar with is chlorophyll. Chlorophyll is receptive to the 'blue' (0.44 um) and 'red' (0.66 um) wavelengths of the visual spectrum. However, experimentation by Loomis (1965) found light absorption in four different plant species (not orchids) to be 92% in the blue wavelengths (0.4 - 0.5 um), 71% in the green-yellow wavelengths (0.5 - 0.6 um), and 84% in the orange-red wavelengths (0.6 - 0.7 um).

What does this mean to us as orchid growers? If a plant is significantly receptive to wavelengths other than 'blue' and 'red' one can hypothesize that photosynthesis is taking place in the xanthophyll (0.5 - 0.6 um) and carotenoid (0.6 - 0.7 um) pigments in the leaf cell. Could this be nature's way of providing back up systems? Or, since the bulk of the sun's radiant energy is expressed in the yellow-green spectrum, plants are simply taking advantage of the bounty by utilizing it.

How does this hypothesis effect the artificial lights we select for our plants? It could mean that less emphasis should be placed on spectrum and more on intensity. Either way let your plants' responses be your guide!

Evaluating Plant Response

What do we look for in a well-grown plant? That, of course, depends on which orchid you are looking at! Lime green leaves, good upright growths, and vertically held new shoots are indications of proper lighting in Cattleyas. Vandas too, should have light green leaves. Dendrobiums should have light green leaves, with vertically held growths. Each successive new growth should be bigger or at least as big as the previous. The common factor with the above, is they are all high light orchids.

Some of the same manifestations can be observed in medium light orchids as well. Each new growth on your Oncidiums should be larger than the previous. Look for leaves that are a bright green, not dark green. Some like Onc. Sharry Baby 'Sweet Fragrance' AM/AOS produces 'freckles' towards the ends of the leaves when exposed to high light conditions!

Low light orchids can be trickier to evaluate. I like to see a faint edge of maroon on the leaves of Phalaenopsis, when anthocyanin is naturally present. If not, as in violacea and its hybrids, I like to see a glossy, bright green leaf. The new growths in Paphiopedilums should not look like they are stretching towards the light. Miltoniopsis should have successively larger growths and a good gray-green color to the leaf. But, the most important characteristic of all is BLOOM.

95% of the time, when an otherwise healthy orchid is not blooming, it is because of not enough light!

Measuring Existing Light

Light can be expressed in several different ways. Most horticultural texts will speak in terms of foot-candles. Technically, a foot-candle is the amount of light cast by one candle at a distance of one foot. An inexpensive light meter, such as those offered by Hydrofarm or through Charlie's Greenhouse Supply, will give you a baseline number to work with.

You can also use the built in light meter in your SLR Single Lens Reflex camera. To do so, place a piece of opaque white paper on a pot at leaf level. Set the film speed at any ISO setting and aim the camera so that the paper fills the view frame. Adjust the lens opening (f-stop) and shutter speed until the meter shows a perfect exposure. Calculate the number of foot-candles with this formula: (10 X f2){division symbol}(t X ISO)=FC, in which f is the f-stop number, t is the shutter speed in seconds, and ISO is the film speed. For example, with the ISO at 25 and the shutter speed a 1/60 of a second, a lens opening of f/2 indicates illumination of approximately 100 foot-candles.

Remember that a light meter will read in the yellow-green spectrum only!
Adding Supplemental Light

If you grow on a windowsill, there are products on the market that can boost your not-so-perfect light. I recommend using incandescent, not fluorescent bulbs when boosting natural light. Fluorescent bulbs do not provide high enough intensity and must be placed close to the plants to be effective. In doing so, a lot of the natural sun can be blocked.

The Wonderlite is a 160-watt, self ballasted halogen bulb. It works on regular 110 house voltage. You must use a porcelain socket with a high enough rating so as not to cause overheating. It is widely advertised in most horticultural magazines. The cost of $50.00 per bulb seems prohibitive, but this bulb does provide significant intensity in the blue and red wavelengths to be used as a sole source of light. Like most incandescent bulbs, it provides a narrow beam of light, which can be limiting. It is an effective light source at a distance of 2 - 3 feet, so flower spikes can be accommodated.

Grow 'n Show type bulbs are readily available in most hardware stores and they are inexpensive. They may or may not provide significant blue/red spectrum, but in the higher wattage's, should be good supplemental light. I would not use anything less than a 120-150 watt bulb. By the time you get a 75-watt bulb away far enough from the plant to cover its leaf spread, the intensity has dropped off significantly.

Remember that light intensity falls off by the square of the distance!

Using Artificial Light as the Sole Source

Fluorescent lights are the ones we all grew up with and I still use them today for certain applications. The minimum array that I recommend is 4 tubes of 40 watt, 48" bulbs. That should give you about 1000+ foot-candles at the very center. The light intensity decreases towards the ends. These are most appropriate for growing low light orchids and starting seedlings. The plants must be within 6-8" of the bulbs and this can cause problems with elongating spikes. Be sure to use fans to move stagnant air between the leaf surface and the bulbs. Replace tubes annually, the red/blue spectrum decreases intensity the fastest.

Of some commonly available brand names: Grolux Wide Spectrum is O.K. in the red/blue wavelengths, but the regular Grolux is not! Avoid any brand that uses the term 'true color', these tubes will be high in the yellow-green wavelengths. Are Verilux worth the extra money? In my opinion, not!

High Intensity Discharge lights use either a halide or sodium gas as the source of illumination. In most cases the bulbs last about 1 1/2 to 2 years. They produce a sufficient intensity of light to be used as a sole source of illumination. With HID's light is no longer a limiting factor. Hobbyists can grow even the most demanding of high light orchids. They do produce a certain amount of heat and if you want to grow Pleurothallids, this will not be the light source for you! However, intermediate to warm growing species and hybrids will be quite happy with your conditions. Air circulation will be necessary to circulate warm air and you will have to provide an active source of humidity. Plants will dry out quicker and you may have to alter potting medium to accommodate this change. HID's are the most efficient source of light currently available, providing the most foot-candles per kilowatt. As the bulbs age, the spectrum fades uniformly.

The new ArgoSun and SunAgro bulbs made by Sylvania provide the broadest spectrum on the market and are worth the extra you pay for them. I do not recommend using sodium bulbs as a sole source of illumination. In personal observation, sodium HID's have produced more crippled flowers and unusual spike growth in Phalaenopsis than any other type of bulb. Paphiopedilums showed unthrifty growth and sodium light seemed to encourage spider mites more than metal halide.

Determining the Photoperiod

Once you have made the decision to use artificial lights either as a supplement or sole source, how do you determine how long to leave them on? Photoperiod is the amount of time that a plant is exposed to light. The 'quality ' of light is the duration (photoperiod) as effected by intensity and the rate of photosynthesis is proportional to light intensity. How do you put all this information into practical use? We can measure intensity with a light meter to obtain foot-candles. A practical unit of measure then, would be Intensity X Duration or 'footcandlehours'.

Let's put this into a practical application. Cattleyas are high light orchids requiring a good southern exposure, getting five to six hours of direct sun (in the Mid-Atlantic States). When setting up an artificial light source for them, I would want an exposure of 2500 - 3000 foot-candles, without taking into consideration the length of exposure. But this is an essential element in the equation. I can use the photoperiod to either make up for a lack of intensity, or as an aid to condition a plant to a higher light source. For example, suppose my light meter reading is 1800. This is a little shy of my ideal. I can use a longer photoperiod to meet its light requirements. 1800 foot-candles X 16.5 hours = 29,700 footcandlehours. My ideal range for a high light orchid would be between 50,000 and 20,000 footcandlehours.

Footcandlehours is an arbitrary unit, but it can be used as a means of comparison. Take an ideal condition for example. If my meter reading is 2500 foot-candles, I would want to expose this plant to no more than 16 hours of light to give it a factor of 48,000 footcandlehours. If I had taken this plant from an underlit condition, I could use a very short duration of 10 hours to prevent burning. I could then increase my photoperiod over several weeks to gradually bring it up to my ideal.

My ideal range for footcandlehours for low light is from 37,500 - 15,000. In a typical fluorescent light set up where my meter reading is 1000 foot-candles, I would want to leave the lights on for 16 hours to give a factor of 16,000 footcandlehours. This should successfully bloom a Phalaenopsis.

Always remember to make changes from low light to high light on a gradual basis!

Winter Under Lights/Summer Under the Stars!

Fortunately, our plants can not read books! I know many hobbyists who successfully bloom orchids that don't 'go by the book'! One way to get around less than perfect light conditions is to utilize the good summer weather (Northern Hemisphere!) out doors. However, there are some factors that must be considered before doing this! Life inside is very 'soft living'. When moving your plants outdoors, gradually expose them to higher light and drying winds. Start off by putting them in the deep shade of trees or buildings. Then gradually move them to their ideal light conditions. This process is called 'hardening off'.

Don't be tempted to put different types of orchids all in the same spot for your convenience. Work the micro-climes that exist in your yard. I very successfully grew Pleurothallids under the Hemlock trees on the north side of my house, even though our summer temps get above 95F!

There are some draw backs to out door living though. What happens if you get a period of rainy weather? For those that need to dry off, it may mean bringing some plants under cover! The summer of 1996 for us was very wet. A good friend lost many specimen-sized standard Cattleyas because they got too wet! I don't recommend putting Phalaenopsis or Paphiopedilums outside if your summers have a tendency to be wet. Both of these types of orchids are prone to either crown or basal rot and water standing in the crowns or leaf axils will favor that.

What do you do about pests? Hang your orchids in trees or get them off the ground in some other way. Earthworms, sow bugs, ants, and millipedes will find orchid bark a pleasant home! Most major orchid pests will not be picked up outside. Scale and mealybugs are usually species specific and will not transfer from out door plants. Slugs and snails are not as picky and will like to eat orchid flesh! I use adhesive backed copper foil tape to band the legs of the tables that I use to house my summering orchids. The slimy creatures will not cross a barrier of copper!

When do you bring them in? That will depend on the type of orchid. Most folks around here leave Cymbidiums out until almost Thanksgiving (mid November) or until the nighttime temperatures get down into the 40's (F). On the other hand, Phalaenopsis are usually brought in near Labor Day (early September) or when the nighttime temps dip into the 60's (F)

Summertime can be easy living for your orchids, but remember the nature will not always provide the right conditions for your orchids. Don't neglect them!

Bibliography

The Essentials of Orchid Growing, Morrison, G. C. and Webb, M. A.
Gardening Under Lights, Murphy W. B. and Time-Life Books
HydroFarm Gardening Products Publications
Growing Under Lights, AOS videocassette

Go Back to Index

TOPIC TRANSCRIPT

Present were 30:
Barbara
Gail
KB Barrett
MaryLou
Sam
Clare
Andy
Rick
Richard WPB
Dan
Carol
Kevin new!
Jason
Maxine new!
Hallie
John
Paula
Marla new!
Jim K.
Guy Cantor
Fleur
Sparky Steve
Matt
Leslie
RedfernNH
emddvm11
Ken
Ed
Evlyn
PeterLin

gaillevy (Boca Raton, FL.)
Richard. What ever happened to your missing plants?

Richard in West Palm Beach
Hi, Gail -- got my plants -- at least some of them. The shipment arrived Dec. 21 (so they say). I think it arrived on time and they just misplaced it. I trashed 229 plants and accepted the rest. They let me go through them individually and select what I thought would live without problems. BTW, I was amazed at the great condition of many of the mature plants. I got 20 Rhy. gigantea 'Red' X 'Spots', trashed one and the remaining 19 are all spiking with anywhere from 1-3 spikes!!

gaillevy (Boca Raton, FL.)
Well, Richard, that sounds like decent shape to me! Sounds very good.

runnerRick (Rick in Concord, CA. Diablo View OS, AOS)
Carol, can you tell me how to raise the Dipteranthus (pustulatis)???

NativeOrchid (Carol in Maryland)
runnerRick, I have several Dipteranthus...little weeds, aren't they? I keep in intermediate conditions, intermediate light, and mist daily.

NativeOrchid (Carol in Maryland)
I'm on, if anyone has anything to ask/say about growing under lights. Andy will have pics for folks to see.

ChuckMyr
Greetings Carol and everyone else, I grow under lights in a home-made wardian case.

NativeOrchid (Carol in Maryland)
ChuckMyr, what do you grow in your Wardian Case?

orchidnut (Sam in Lincoln, NE)
I have a question....How can one deal with the heat problem when using HID's?

ChuckMyr (Chuck in Austin, MN)
Carol, almost exclusively species Paphs.

marilyninOttawa
Carol. I was happy to see that you recommended Gro n Sho tubes. They certainly are the least expensive here in Canada (about 1/4 the price of Grolux) and by our measurements, produce equivalent quantity and quality of light.

NativeOrchid (Carol in Maryland)
Dealing with heat.....use fans! But remember, if we are to be successful orchid growers, we must choose the right orchids to grow. I maintain my light room conditions between 58F (winter nights) and 85F (Summer highs). I cheat and use some AC in the summer. BUT, I still limit my collection to intermediate to warm orchids!

KB Barrett (Kathy in N Calif.)
Clare, my big problem with growing under lights is keeping the humidity anywhere above 30-40% and keeping the heat down below 85F. I'm in N. Calif, inland from SF, and it can get brutal here. I've tried small swamp coolers, to no avail, and 'Sick Room' humidifiers which are a joke. The best that worked for me was 'Damping down' the trays the plants were in, tho' I got leaf spots bad in the middle of last summer. It's a frustrating mess.

Clare in LA
Carol, what's the lowest I can go on light conditions? Or should I say, what orchids tolerate the lowest light conditions?

KB Barrett (Kathy in N Calif.)
Another problem I have is that my plants are in a spare bedroom, not a basement where you can sling water around and not worry about warping walls or floors.

marilyninOttawa
During winter, when I grow under lights, I 'use' the heat from the ballasts to boost the day temperature in my growing tent. I realize that HID ballast heat could be considerably more than I need. Any suggestions other than fans to deal with the excess?

NativeOrchid (Carol in Maryland)
Kathy, have you tried using a small AC unit to pre-cool the air going into you swamp cooler? Evap coolers don't work here in the Mid-Atlantic states. So far, my humidifiers and my AC unit balance in the summer to give me just the right conditions. I use a Bionaire humidifier. Made in Canada, but available around here. It is a 3 gal and I refill daily. My grow space is 12 X 24 ft.

orchidnut (Sam in Lincoln, NE)
And on the other end....what kind of orchids will do good under fluorescent lights, besides phals, and paphs?

NativeOrchid (Carol in Maryland)
Low light orchids ...Phals, Paphs, Miltoniopsis, Masdevallias, Pleuros...pretty much cover it.

Clare in LA
Kathy, that's sad. I guess windows are the best. The idea of wet stuff in my room does not appeal to me.

NativeOrchid (Carol in Maryland)
Marilyn - I don't have 'excessive' heat build up. Even in Arbec's store....we would use ceiling vents and fans to exhaust the top air layer. That did make maintaining humidity a constant battle.

KB Barrett (Kathy in N Calif.)
Carol, I hope to build a Greenhouse before the summer comes, but if not I'll keep that in mind, maybe I'll just have to bite the bullet and get a window A/C.

runnerRick (Rick in Concord, CA. Diablo View OS, AOS)
Marilyn, the only use that I can think of for the extra heat would be to heat water. Can you duct the water nearby?

Andy NVA (Northern VA.)
Ready for a pic? picture

orchidnut (Sam in Lincoln, NE)
Does that have a mover on it Andy?

runnerRick (Rick in Concord, CA. Diablo View OS, AOS)
Good pic Andy. Is that at the Arbec store??

Andy NVA (Northern VA.)
Yes, Sam. many HID lights are put on 'tracks' to move the light over an extended area-getting more for your money. Yes, Rick. That was one of the first lights installed at Arbec Orchids.

marilyninOttawa
Very nice pic Andy!

NativeOrchid (Carol in Maryland)
Sam, I prefer using tracs to move my HID's ...more even plant growth.

cattleya lover ((Maxine from Central Florida))
Clare...No, I purchased a 'Green Ching Hua' Catt today and it has a slight fruity smell. Excuse my ignorance, but the digbyana, is that catt or one of the other species?

Clare in LA
Sam, how much light do the paphs need. Or how close do they need to be to the fluorescents, or how long does the light need to be on?

NativeOrchid (Carol in Maryland)
Kathy, get a larger humidifier. The small vaporizers (sick room type) are fine for just a few orchids.

marilyninOttawa
That is a good idea, Rick. The water is right next to the growing area and I always have to mix some hot with the cold (in winter) so as not to shock the plants when I spray.

KB Barrett (Kathy in N Calif.)
Clare, I just got too big too fast! And I didn't judiciously purchase plants that were right for my environment. Either too large, or hi light requirements.

NativeOrchid (Carol in Maryland)
Clare, I grow my mottled leaf Paphs in about 1000+ footcandles, standards and mulitflorals I go as high as they will take....2500 foot candles. In all cases at least a 16 hour day.

KB Barrett (Kathy in N Calif.)
Carol, can you name a larger humidifier?

NativeOrchid (Carol in Maryland)
Kathy, Sears has some room humidifiers that we used at the store for a while.

Andy NVA (Northern VA.)
Thanks folks - They're Carols pic's actually. She has some more.

Clare in LA
Is one artificial light source better/ or different than another?

orchidnut (Sam in Lincoln, NE)
One would need an HID for plants like ascocentrums, small catts, etc., then?

Andy NVA (Northern VA.)
Clare: check out http://geocities.datacellar.net/RainForest/3297/LIGHTS.html. That will answer your questions on different light sources

NativeOrchid (Carol in Maryland)
Sam, I do great with Ascocendas/centrums. I grow Brassovolas really well. Den phals bloom like crazy under HID's...around here they can be a little tough to bloom on a windowsill. Mini catts respond well too....if they have a lot of Soph. coccinea in their background, they will need those cool nights, though.

Hallie (King George, VA, USA)
Carol, how often do you change your HID lamp bulbs? My 400W metal halide is about 18 months old.

Andy NVA (Northern VA.)
picture

Clare in LA
Thanks, Andy. Got to think of those things for my future move.

runnerRick (Rick in Concord, CA. Diablo View OS, AOS)
Andy, what is the available light equivalents at the plants from the different sources shown?

Andy NVA (Northern VA.)
Second pic. posted shows the different light spectrum captured by the camera. Notice the yellow of the sodium and blue of the halide.

orchidnut (Sam in Lincoln, NE)
What would be the smallest HID light that you would recommend for an area 3ft x 5ft?

Andy NVA (Northern VA.)
That's a question for Carol...

NativeOrchid (Carol in Maryland)
Hallie, I change mine when they start to go bad. About every two years, but they could be changed at about 18 months for best performance. But that depends on how long you run them (day length)

Hallie (King George, VA, USA)
I'm running about 14-15 hours. BTW, do you change day lengths with the seasons?

NativeOrchid (Carol in Maryland)
Sam, what are you growing? High light orchids or low light orchids?

orchidnut (Sam in Lincoln, NE)
I'd say mostly medium to higher light ones.

Hallie (King George, VA, USA)
You really can grow some 'high light' plants under metal halide--I've got some Equitants blooming right now, and bloomed a big Brassia last summer.

ChuckMyr
Sam, why not just build an 8'x8' setup. I bet you could fill it fast enough! ;-)

NativeOrchid (Carol in Maryland)
Hallie, I don't change my day length...for one thing I run 4 HIDs on three timers..I'm too lazy. A plant pathologist friend pointed out to me that tropical orchids in their native habitat don't get that much day length difference, being equatorial.

orchidnut (Sam in Lincoln, NE)
Well, Chuck....I'm kind of limited on space. I live in an apartment.

Hallie (King George, VA, USA)
I decreased the length of time the HID was on last summer, to cut down on heat. Hope to put everything from it outside next summer.

NativeOrchid (Carol in Maryland)
Sam, depending on the number of high light orchids, you might get by with a 250w...but I would probably go with a 400w and raise it high enough so as not to burn the orchids in the center.

orchidnut (Sam in Lincoln, NE)
Carol, would a 250 watt be a good choice for that size of area?

NativeOrchid (Carol in Maryland)
Hallie, I killed almost all my equitants this summer when I had my light room electricity 'heavied up'! Lucky you!

Clare in LA
Good point, Carol. Never thought of that.

Andy NVA (Northern VA.)
picture

Clare in LA
That I like Andy. Especially the movable shelves.

Fleur
Sliding shelves, what a good idea.

NativeOrchid (Carol in Maryland)
Sam, I live alone and don't have that problem. However, growing under lights, if you have space to grow only furthers the addiction. I started with a 8 X 10 ft area and it has grown to 12 X 24 in 10 years. I will have pics of my light room (and my newest 'invention'....overhead rolling tables) at a later time. I just got the first one built and haven't had time to photograph it yet.

GuyCan2 (Guy in Sydney)
As this is a talk on growing under lights, and I was late, has anyone raised what you need to grow flasks? I use GroPlus fluoro tubes but am told ordinary fluoro tubes are ok.

orchidnut (Sam in Lincoln, NE)
Hehehe..I don't think I can get any more hooked than I already am! ;-)

Andy NVA (Northern VA.)
Guy - Flasks don't really need special light. I put mine under a fluorescent light strip. Remember - in flask seedlings don't photosynthesis. They get their nutrients from the media.

NativeOrchid (Carol in Maryland)
Fleur, the person who built the sliding shelves used the hardware that is used for a heavy drawer.

ChuckMyr (Chuck in Austin, MN)
What are everyone's favorite fluorescent tubes?? Right now I'm growing under half grow-lux and half cool whites. Could I do significantly better without too much more cost??

NativeOrchid (Carol in Maryland)
Chuck, sounds good to me. My opinion...intensity is MUCH MUCH more important than spectrum, and spectrum is what you pay more for!

Tex1 Dan (Dan from Wharton, Texas)
GuyCan2, When Pete Lista was alive (he bred phals) He had flasks all over the house under every table lamp. Of course, they were incandescent bulbs. He wasn't concerned ....and he had hundreds of flasks all over the house.

orchidnut (Sam in Lincoln, NE)
Could you use the halogen spots at the local hardware then?

KB Barrett (Kathy in N Calif.
Chuck, I started with those Vita-lite power twists, at $98 for 6 of them, boy whatta rip!!!! I'm now happy with GE Sunshine and plain old cool white.

ChuckMyr (Chuck in Austin, MN)
Carol, when I look at the grow-lux bulbs, they don't 'look' as bright as the cool whites. Are they really less intense, or is it a trick of the eye (blue/purple vs. white looking light)

runnerRick (Rick in Concord, CA. Diablo View OS, AOS)
I think that the only thing one has to watch with flasks is that they don't get too hot. I keep mine right on the shelves with the plants although usually on the second shelf down so not to get too much direct light (I don't grow under lights) but the sun is fine in Catt. like conditions. Just watch the heat.

Tex1 Dan (Dan from Wharton, Texas)
Andy NVA, If the seedlings or protocorms are green, and I know they are....they do photosynthesize nutrients, water and CO2. They must produce food. They just have all the nutrients and water they need in the agar.

NativeOrchid (Carol in Maryland)
Sam, Be careful! Some of those give a very powerful, narrow beam. You could burn a hole in a leaf and leave the rest of the plant underlit. Do you have a light meter to take to the store with you?

orchidnut (Sam in Lincoln, NE)
Yes, I do

NativeOrchid (Carol in Maryland)
Kathy, don't use anything that says 'Sunshine' if you are concerned with spectrum. True color and sunshine indicate a bulb that is high in the yellow-green range. Chuck, spectrum can fool the eye. We see yellow-green spectrum the better than infra-red and ultra-violet.

kawacym (Jim in San Jose, Ca.)
Anyone try the 'Daylight' type of fluorescent tubes? They appear to put out more light than cool whites.

Andy NVA (Northern VA.)
Dan - I've been told that very little photosynthesizing is done in flask. Respiration does take place which makes the necessary food for the plantlets. Next time you flask, make an extra one to experiment with. Put it in the dark and watch the protocorms grow into plantlets. The will be without chlorophyll until you expose them to light.

Andy NVA (Northern VA.)
picture

Clare in LA
So, now we have splash guards. Does this mean we have an automatic mister going as well?

ChuckMyr (Chuck in Austin, MN)
Carol, that's what I thought, but I don't have a light meter so thanks for the verification!

nodosa (Ed in SAT
Evlyn, we add acid to insecticide spray water first to set the pH and reduce the chance of alkaline hydrolysis. We add acid last to fertilizer solutions (after the dry stuff is diluted) so it won't precipitate anything out of the solution. If the fertilizer has any filler (usually some form of chalk) you can get a gunky goo (this is the technical term) if you go the other way.

Andy NVA (Northern VA.)
Ed-Your comments on protocorm/plantlet photosynthesis in flask?

NativeOrchid (Carol in Maryland)
Clare, The guy who built that particular light cart must have been a messy person! The splash guard might keep things on the shelf more humid, though!

Andy NVA (Northern VA.)
The splash guard may help keep plants on the shelf too. Wish I had them on my greenhouse benches!

PaphioDePaphio
I grow some of my plants on this thing called a RotoGro.

Andy NVA (Northern VA.)
Is that like a light cart, Paphio?

Tex1 Dan
Andy NVA, I never tried to put them in a dark area. We always put them under table lamps. How long did you keep them in the closet. You can put any plant in darkness for a period of time, but eventually they will need light. I need to do some more reading.

PaphioDePaphio
And some others.. I use DuroLite 150watts

Fleur
What's a rotogrow?

PaphioDePaphio
Andy: Yep... light cart and rotates around the light like a ferris wheel ...moves a step every 15 minutes..

Andy NVA (Northern VA.)
picture

bmtorchids (Barbara from N. Ca.)
That's some good basement setup.

NativeOrchid (Carol in Maryland)
Barbara, that is the largest light set up that I have ever seen! ...and he was not commercial!!! He pumped water into the room to water and pumped water out of the bottom of the benches when they got full! He mixed his fertilizer in two 55 gal drums hooked up together.

PaphioDePaphio
Fleur: It's a new light cart that is available in USA. 4 tubes of fluorescent light in the middle and 6 to 8 trays that rotates around it. Like a ferris wheel.

orchidnut (Sam in Lincoln, NE)
Carol...now THAT'S an orchid addict!

nodosa (Ed in SAT)
Andy, I think you had it about right when you said little plants in the flask are sugar feeders. Light levels can be very low and I doubt that growth spectrum enhanced bulbs are worth much or even a good idea. We put new flasks in an incubator with 70 degree bottom heat, then move them to a flask area as they transition to chlorophyll and photosynthesis. If you overstimulate the tiny ones, they can harden and slow way down in rate of growth. At least, such is my opinion.

Tex1 Dan
Ed, don't you think the goo you're precipitating out is the calcium in the fertilizer. Calcium is notorious about falling out of solution. Also, many of our water sources have large calcium contents adding to the problem. We have the same problem with certain ag fertilizers.

Fleur
A friend of mine has a wire frame like a pyramid that hangs from the greenhouse roof, for his hanging plants. Similar thing.

Andy NVA (Northern VA.)
picture

bmtorchids (Barbara from N. Ca.)
That's some good basement setup.

PaphioDePaphio
Fleur: Ahhh, but this system is kinda bad. Only good for seedlings and Phals.

Evlyn
Are we talking BIG BUCKS on this ferris wheel contraption?

orchidnut (Sam in Lincoln, NE)
Hey!! Now that's my kind of set-up!

PaphioDePaphio
Evlyn: Kinda... about $500. Check out Dragon Argo Products. they carry it. Got a Web Site on Orchid Mall.

Clare in LA
I'm amazed at how close all the plants are. I guess if they get sufficient light from the top it doesn't matter.

nodosa (Ed in SAT)
Hi, Dan. Not YOUR fertilizer, surely. I'm sure the precip is primarily calcium - probably CaCO3. Thing is, it is coming from use as a filler in the fert sack because it is stable and cheap. We see some fertilizers with half the volume and the same or higher nutrient value.

Fleur
Andy, the lights on tracks, are they moving?

runnerRick (Rick in Concord, CA. Diablo View OS, AOS)
Ed, what is a good source of soluble calcium without adding nitrogen?

Andy NVA (Northern VA.)
Fleur-Yes they take 20 minutes to move 6 ft.

Clare in LA
Ok, if and when I put together a Wardian case for the pleuros what type of light source should I use?

PaphioDePaphio
Clare: For Pleuros? I'd use VitaLite. they are great.

NativeOrchid (Carol in Maryland)T
Clare, they are low light babies..so fluorescents will do fine. You may even want to but the ballasts a distance away to keep the heat down.

Tex1 Dan
Ed, it is common in many fertilizer blends. We use it in some of our dry fertilizer blends we scatter on commercial fields.

NativeOrchid (Carol in Maryland)
Paphio, Vitalite's are too darned expensive for what you get...I'm not wealthy!

nodosa (Ed in SAT)
Rick, we have 234 PPM CaCO3 in our ground water so adding Calcium is not a problem. A little gypsum is cheap, available and easy to use. Same for dolomite. You can use a little ground oyster shell in your mix (get it at a store that sells chicken feed). Don't use dry cement - it is too caustic.

PaphioDePaphio
Carol: Go to a hardware store to get them, not in the catalog. They are alot cheaper.

runnerRick (Rick in Concord, CA. Diablo View OS, AOS)
Ed, I was thinking of using lime but not sure about how soluble that is.

NativeOrchid (Carol in Maryland)
Unless someone has a last question, I'm going to sign off too!

ChuckMyr (Chuck in Austin, MN)
Goodnight, and thanks Carol!

Tex1 Dan (Dan from Wharton, Texas)
Ed, what are you using the gypsum for?

Clare in LA
Thanks, Carol. Going to keep all this in mind for the move.

nodosa (Ed in SAT)
Rick - lime is pretty hot for a small flower pot. Great on the farm - ask Dan!
Dan - gypsum is a cheap source of calcium and magnesium.

sparkysteve (of Boca Raton Florida
Ed are you saying to ground up 'dry-wall or 'sheet rock'?????

Tex1 Dan (Dan from Wharton, Texas)
Lime can be very hot...You have to watch how much you use. I notice on my roses and geraniums, that after time, I need to add some hydrated lime, due to the media getting very acid over time. What about using bone meal. Shouldn't be as hot on the plants, although I'm not sure how available it is!

Tex1 Dan (Dan from Wharton, Texas)
I forgot about the magnesium. We don't have the need on row crops in our area, due to fair amounts in our soils, but I know orchids have a fair need!

nodosa (Ed in SAT)
Sparky - you can get an awfully big bag of gypsum for under ten bucks. Still, it is about the same as wallboard chalk if you want to do it the hard way.

KB Barrett (Kathy in N Calif.)
I think Rick was asking because he uses straight RO water on his plants, wanted Ca with out the Na N or other ions.

Tex1 Dan (Dan from Wharton, Texas)
You could always blend so much tap water with your RO water to add some CA.

KB Barrett (Kathy in N Calif.)
Dan, that's what the consensus was, I can't recall why he didn't want to do that.

nodosa (Ed in SAT)
Kathy, salt in the water always means we must be very careful about pH. Keep it above 6 and below 7.

cattleya lover ((Maxine from Central Florida))
One question before I go. What do y'all think of dividing plants up. I gather most of you are against it. And what are your reasons?

sparkysteve (of Boca Raton Florida
Ed---that's why I dip my plants in the pool from time to time!! has good pH.

KB Barrett (Kathy in N Calif.)
Ed, That will keep what, the sodium salts in suspension? The Ca and Mn Mg in solution?

nodosa (Ed in SAT)
Maxine: little plants grow; big plants bloom.

sparkysteve (of Boca Raton Florida-
It's a 'mental state' when in a big pot---it looks like there are more new growths

Fleur
I tend to just pot up, but then my plants don't grow very big anyway and a large plant looks so nice in flower.

nodosa (Ed in SAT)
Kathy - we want a pH that will make all the nutrients in the solution available. Plants seem able to pick and choose to some extent. If we get the pH too low, however, we will make the solution acquisitive, which will raise the salt level. RO water is already acquisitive and dissolves everything in its path. It must be watched like a hawk and most hobbyists do not have the capability to do that. We are not RO fans for the smaller grower.

cattleya lover ((Maxine from Central Florida))
So, it appears that if anyone wants more of their favorite orchid, you all suggest flasking it or mericloning?

sparkysteve (of Boca Raton Florida-
Best way for someone to have a division is to give it to them to repot and tell them to keep a piece!!!!

nodosa (Ed in SAT)
Maxine: nope, we whack off a piece of the plant and share it. BUT we think a bit about the recipient in relation to the set back of the plant. If the recipient doesn't tote well, we put them on the list for a piece 'a little later'.

cattleya lover ((Maxine from Central Florida))
This has been a very informative evening. Thank you all for the advice. I must go now. Bye.

sparkysteve (of Boca Raton Florida-
Maxine---just listen to what you hear and use 10% of it!!!!!!

nodosa (Ed in SAT)
Bye, Maxine. Heck, Steve. If nobody uses my stuff how am I supposed to know whether to try it or not?

sparkysteve (of Boca Raton Florida-
GOOD POINT! If their plant dies then you know not to use it!!!!

KB Barrett (Kathy in N Calif.)
OK, guys, I'm all in, too.

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PLANT PHOTOPERIODISM
by Daniel Mascheck
8 Jan 97

We note in plant physiology, that there are three major groupings of plants. Those that are long day plants, short day plants and day neutral plants. They all respond to flowering depending on the day length. As you will note, those that flower in the Winter would be short day plants, those that flower in the Spring or Summer would be long day plants, those that flower anytime of the year are day neutral. Many orchids grown in the tropics will need small differences in day length to initiate flowering, due to the small day length variation during the year. By making extensive crossing you can shift one type to another.

Many people are unaware that all the milo or grain Sorghum grown in the USA originated in Ethiopia. They are very short day plants in their native habitat. Due to this characteristic, they will only bloom around November or December when grown in the USA. This doesn't allow enough time to produce grain before a freeze. By extensive breeding...they change the characteristics of the introduced milo from Ethiopia, to a day neutral type which we can successfully grow in the USA!

I worked part time while at college, in the Sorghum Conversion Program for the USA. That's one of the main reasons I'm aware of plant photoperiodism. We use the terms day length...inducing flowering. In reality, you find out it's actually the night or dark period that makes the difference, not the day or light reactions. Someone years before me, coined the terms short day, long day or day neutral, before they understood the reactions, so......the terms stuck.

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TRANSIENT LIGHT: DOES IT AFFECT PLANT GROWTH?
by Ed Wright
3 Jan 98

This is a very complex subject and one in which answers are developing here and now. Let me see if I can summarize several disciplines.

Virtually every living organism has several circadian or biological clocks that time automatic, autonomic and other non-voluntary aspects of life. Were it not so, we would consume enormous energy and an inordinate proportion of our neural capacity just with turning things on an off: metering adrenalin to meet the body's needs, introducing bile, sleeping, waking, make and combust sugar, store starch, all the countless supportive functions that are essential for sustaining life but are too elusive to permit organisms to do them voluntarily. People and plants, puppies and porcupines, we all depend upon circadian clocks.

There is mounting evidence that these clocks are numerous in living organisms, that they are located in several areas but are not randomly sited, that they are operated by protein photoreceptors. These proteins all seem to be sensitive and reactive to blue light. Strangely, our brain clock seems to be adjusted by receptor cells in the eye retina that react to blue light but are not the cells used for vision. Weird. Anyhow, if you suffer from jet lag, you may need to set one or several circadian clocks. In plants, we can light control some responses through light stimulation.

Now, the issue and I know you are good and ready for that! Yes, light can affect plants, but we are changing our thinking about the theory that even very weak lights can do so. Light is an energy representation and it obeys the rules of several areas in physics. The most essential thing to remember is that light energy varies as the square of the distance. In other words, if you measure a light energy at three feet, then the light energy at six feet will be one fourth as great. Extrapolate this to your neighbor's yard light and the light energy level becomes pretty small. In addition, only certain light frequencies are highly influential in plant growth. That is why we perceive growth enhancing tubes as being dim: they spike the red and blue specific frequencies and attenuate all others so the light energy is channeled into the narrow effective ranges at the red and blue frequency peaks for photosynthesis.

Bottom line is a layer of fiberglass and one of shade cloth will shield your plants pretty well from stray light. I would not want my benches exposed to growth enhancing bulbs at night, but one might do specialty growing that way. In the interest of safety, I'd hang some cheap fluorescents well above my plants and save stumbling around in the dark when the heater needs attention. While short bursts of light can affect plants, I doubt they will be greatly harmed. They just need to get some sleep like everyone else.

Sorry to be so windy. I don't know how to simplify this subject. I would point out that I have generalized extensively in this discussion simply because without that, there would be no end to it. Speaking of which, this is. Ed

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