Factors that contribute to phal spiking?

[mehitabel]

There seem to be three theories of what causes winter-blooming phals to set spikes in the fall.

A. A cool-night period of two-three weeks with nights to 60-65F
B. Kevin's theory that what is needed is a diurnal drop in temps of 10-15F.
C. A necessary (tho not sufficient) cause is *day* temps below 80F. (Thanks to FlBob for the url)

http://www.staugorchidsociety.org/up...sis_Part_3.pdf

Of these, I tend to favor Theory C. And notice the lower day temps are not enough by themselves. The finding is that temps above 80F inhibit spikes.

So I wanted to add some observations I made of patterns of spike setting this year:

Spring spiking:

1. Do phals set spikes only in fall? No. I got 38 spikes set on my phals this spring.

2. The pattern of spike setting corresponded closely to *the increasing intensity and duration of light* in spring.

12 in my west window in Feb & March. The afternoon sun goes above the house next door in late afternoon in March, so duration of sunlight in that window increases markedly in March. Ones that set spikes included multifloras and yellows

26 on my indoor/outdoor carts from March thru May. 5 in March, 11 in April, 10 in May. These included multifloras, yellows, and some with clear summer-blooming species in ancestry, esp in May.

3. As the days warmed up June-August, spiking dropped off. 15 total in that period, and all summer bloomers.

Fall spiking:

Spiking started again in late August as the nights (and days) started to cool off. This time I kept closer notes.

1. *They spike when they're ready (ie mature enough)*: Which ones are most likely to spike? By now all the 6" pots with 6 or more leaves have spikes. A few of the ones with fewer leaves are spiking as well, but there's a clear difference between 4 leaves and 6.

In September, 17 spikes were set; from Oct 1 thru today, I have found 6 more.

2. Phals do respond to the cooler days and nights of fall by setting spikes. Spiking started at the end of August, see above for Sept.

3. Those that didn't set spikes while getting cooler nights for several weeks continue to set spikes after brought inside to warmer days and nights.

About the middle of September I realized the outside phals weren't showing any more leaf growth, despite a lot of light. It seemed it must be the cooler days and nights, so I brought them inside on 9/18, putting as many as I could of the bigger ones under T5s in the kitchen (west) window, and the rest downstairs in the plant room.

I was hoping the indoor warmth at least to get some more growth before the winter comes on in earnest, complete with chilly nights slowing growth.

5 spikes were set from 9/18 til the end of September, and 6 now in October.

4. Summer bloomers respond to increased intensity/duration of sun (given they are getting warmth as well). This is the same effect on duration of light that happened in spring, and while sunlight intensity is not increasing, it's still strong.

Three of those spikes were set on blooming phals that were never outside at all. Two of these were summer bloomers that I believe set spikes in response to the increased duration of real sun in the windows-- the sun slants more now so it's in the windows longer.

5. Except for the summer bloomers, the type of phal spiking now is different from those that spiked in spring. Mostly what's spiking are big whites and pinks, but some yellows and multifloras also.

[syndywindy]

A lot of good information, and a lot of observation on your part. You also have a lot of humidity where you are, so I assume that has to be a contributing factor as well. I don't have nearly the number of phals as you do, a few are in bloom right now, a couple have spikes and some are showing alot of new growth, either roots or leaves. I'm too new to all this to have a good grasp as to how mine respond, but you do give good insight to getting phals to set spikes. And for that I thank you!

[mayres]

Good information - though temps certainly have a significant effect on triggering spikes let it be known that I have several in an office environment that is both air conditioned and heated with forced air - phals are at a constant 72 degrees year round with hardly a single degree of variation. The only variable is the amount of light they receive through a NE facing window (a direction I hardly would call ideal, but it's all I have) and I consistently have phals spiking here! There is probably a micro environment near the window that does have some effect but I have not tried to measture it. Windows do not open. Intresting thing is that they do tend to spike/bloom just about any time of year - but more importantly THEY DO BLOOM!

[mehitabel]

Veddy interesting, Mike. Especially the fact that they bloom any time all year. That environment puts the kibosh on the two that emphasize temp drops all right! As you said, they may contribute, but they aren't *necessary*. The U Houston research cited in the url said that they got spiking even at 77F nights as long as the days were under 80.

I keep coming back to "They spike when they're ready".

Synda, yesss! Lots and lots of flowers in the dead of winter! This is the first year I've had a large number of winter-bloomers to be getting spikes from in fall, tho I had quite a few spikes in spring last year as well.

About the climate -- this summer was cool, but most summers here are hottttt and humiddddd. We are consistently about 10 degrees hotter than you, and every storm in the gulf sends moisture here. You may miss a few of those, but don't you get humidity from the lake?

[Ron]

1. *They spike when they're ready (ie mature enough)*: Which ones are most likely to spike? By now all the 6" pots with 6 or more leaves have spikes. A few of the ones with fewer leaves are spiking as well, but there's a clear difference between 4 leaves and 6.

From what I have read and seen from my plants, there is still a lot to learn by us growers on getting them to flowering!
Last summer for about 6 months, our temps ranged from nights of 85F+ to days of 100F to 110F.
This according to all the books spell death to the plants and no flowers.
Well mine hardly finished flowering and up come another spike!.
I think with the modern breeding they will flower all year round if the conditions suit them.
That is the secret if there any secret is there!
(just a drop of 10 to 15 degrees F between day and night)

I keep coming back to "They spike when they're ready".

I agree, well grown and looked after will give you more flower spikes each year.
Thanks for your input as we learn something each day from each other.
Ron

[kmarch]

I should like to point out hat the diurnal temp theory of flowering didn't originate with me. It was routinely spoken of in the first orchid society I joined and since then I have seen it mentioned in several books including Eric Christenson's monograph on Phalaenopsis (p.263). I believe it is one of the currently prevailing beliefs regarding phal bloom triggers.

mehitabel's last 2 options seem to hand in hand in my view as it is usually Autumn when this diurnal temp occurs and during that time, the day time high's are somewhat cooler.

I have only every heard the first option here on the forum. I've never seen it in a book. In fact Christenson recommends that any phal never be grown less than about 62F (about 16C) with only a few species exceptions.

[orchidlover55]

Mehitabel, you said white, pink and some yellow maybe the one's blooming. I bought most of my phals as Noids so I haven't seen 2/3 of my phals bloom yet. I want a yellow one so bad so I am hoping out of the 17 that are in spike I have a yellow one

[mehitabel]

Hi, Kevin. Thanks for contributing to this thread. I am hoping lots of people will add their experiences as well. I like to know what other people are doing and finding out in their growing, because I honestly believe each person has a tiny piece of the secret.

One of my favorite scraps of knowledge is that in the 19th century, Galton found that the *mean* of the guesses of hundreds of people at a fair of the weight of a prize bull was within a few ounces of the true weight. An error of only a very small percent of the true weight. Some of the people guessing were knowledgable, some were totally ignorant. But each had a tiny scrap of knowledge, and when all those scraps were put together, it yielded the true value. A book was written about this type of phenomenon recently, called *The Wisdom of Crowds*. (A crowd can be wrong sometimes, too, of course)

>The Diurnal theory. I did know that you didn't originate the diurnal theory. Lots of phal specialists do talk about it, so I'm not a stranger to it. I mentioned you in that connection only because you have advocated it several times on the board, and I thought that referring to you would help the reader know what I was talking about. So there was no intent to tie it around your neck, honest

As I've said previously when we discussed this, I don't credit the diurnal theory much as a sufficient condition because in this climate, that kind of diurnal temperature change goes on all summer outdoors, while only a few summer bloomers are spiking and winter bloomers definitely not spiking. The U Houston study shows it's not necessary if day temps are below 80F.

>The Cool-D0wn theory: About the theory of the cool-down period, I didn't invent that either. I've been hearing and reading about it since I first became interested in orchids some years ago. I've no idea of the original source, but Bob Gordon *Culture of the Phalaenopsis Orchid* favors it in his discussion of flowering. He discusses masses of cool dry air moving south seasonally in the Philippines, where several of the winter-blooming species originated (p. 85). Todays hybrid phals often contain 50% or more parentage from those specie. On p. 83 he says "The chilling process is called 'vernalization' or promotion of flowering by low temperatures".

His checkist for spike induction is

1. Increase light by 25-40% to 1300-1500Fc.
2. Increase the range of temperatures from 63-85 to 58-90F. Maintain for 3-4 weeks.
3. Reduce nitrogen, give epsom salts, etc etc (Mentions a few other things that might contribute)

>They spike when they're ready theory: p. 87 Gordon sums it all up: "Having said all that, chances are good if you do nothing outside ordinary good growing practices, most of your mature, healthy plants will still go ahead and flower anyway". ie they spike when they're ready

So, summing up, Gordon actually says, none of the factors he lists are actually *necessary*.

>Confoundings: I personally don't think the last word has been written on this subject, because cool nights, cool days, and in fall, short days and long nights are perfectly confounded. Separating out those factors to isolate *the* one, or to prove that more than one is necessary would take a lot more research than has been done. And in fact, my guess would be that, as in many natural phenomena, there is no one *the* factor, but many factors that contribute.

[mehitabel]

Hi, Orchidlover. I like yellows, too. They are definitely way up there, one of my favorite kinds. The range of different types of "yellow" flowers is just enormous. Some of them throw many spikes at once.

Here's to some of your NOIDs being yellow. Yeah!

[PhalPal]

I believe in option 'C'!
However, our hybrids have many influences and it is difficult to figure out which parent is dominant. This makes it hard to know which culture practice will benefit our plant the most.

I have done nothing but water my orchids when dry and have made no changes for the past 3 months. No fertilizer, no babying, my husband was in charge and I just hoped for the best. I will be able to tell you how many 'go ahead and bloom anyway' fairly soon.

[NicC]

Originally Posted by mayres

Good information - though temps certainly have a significant effect on triggering spikes let it be known that I have several in an office environment that is both air conditioned and heated with forced air - phals are at a constant 72 degrees year round with hardly a single degree of variation. The only variable is the amount of light they receive through a NE facing window (a direction I hardly would call ideal, but it's all I have) and I consistently have phals spiking here! There is probably a micro environment near the window that does have some effect but I have not tried to measture it. Windows do not open. Intresting thing is that they do tend to spike/bloom just about any time of year - but more importantly THEY DO BLOOM!

Us window sill growers often have very controlled temperatures in the house but I have done checks on the window sill in my 5 year old condo that leaks like a sieve. On cold days (freezing and below temps) the window sill will get down to the mid to low 60's. I have been fortunate to bloom most of my orchids except the older Catt hybrids(maybe the individual plants are not old enough...)
I would think root temperature and changes in light duration are the 2 most important factors, as with many other plants. In fact, I believe the orchid factories grow thousands of seedlings forcing vegetative growth then force flowering (particularly phals) with root temperature and light duration manipulations. A retailer told me that is how he always has phals. but not necessarily other genera.
Nick

[exasperatus2002]

This was a good read. Thanks everyone.

[mehitabel]

One of the things I'm curious about is how long the spiking continues to go on, both for individual people over time, and for people in different areas. Hopefully, that should tell us something, too.

[Ron]

Hi, Orchidlover. I like yellows, too. They are definitely way up there, one of my favorite kinds. The range of different types of "yellow" flowers is just enormous. Some of them throw many spikes at once.

Well I love them also, I have on flasks order or growing 6 different types.
Here is one curently in flower, just an 18 month old small plant.
My main aim now is to grow Phallies, by joining the "Geeks" forum, I hoped to gain more experience reading what other grower around the world do.
While some only grow indoors and some what limited, mine are grown in a semi controlled greenhouse.
One thing I read about 3 years ago on another forum of nurserymen was that growers in Taiwan & Hawaii were growing Phallies at a heat range of 30C+ continually.
Upon reaching a salable and flowering size they were shipped to the US were they were repotted and kept at 20 to 25 C deg. (70 to 78F) several weeks and the flower spikes started to grow.
This gave them a quick turn over flowering crop.
Maybe we can learn form this idea!
Fun learning anyway.
Ron

[mehitabel]

Originally Posted by Ron

My main aim now is to grow Phallies, by joining the "Geeks" forum, I hoped to gain more experience reading what other grower around the world do. Ron

Hi, Ron. Hey, great minds run in the same circles. Nice to find another phal fan. I decided to specialize in phals when I read that you could gain expertise with them faster than with many other types of orchids because they go from flask to blooming size in a relatively short time (about 18 months) vs maybe 5 years for catts. This gives you many more "generations" of experience in a given time period. The conditions I can provide also favor phals more than other orchid genera.

Since you're interested in what other growers do, have you seen Bob Gordon's book *Phalaenopsis Culture: a Worldwide Survey*? He got responses from phal growers all over the world on a series of questions, and published their answers in this book. It's a small book (I got a perfect used copy for app $14 on Amazon), under 300 pp. I found it very interesting to find out what other people did with their phals. Lots of good ideas in that book.

I've read about the "growing" and then "spiking" culture used by commercial growers for phals. Yes, it's very interesting. Not always feasible for hobby growers to attain that much control over conditions, tho. I'm not a fan of precision in hobbies. Some of the Taiwan breeders have many PhD's on their staff -- no way to match that expertise by reading a few books, either.

[syndywindy]

Originally Posted by mehitabel

Synda, yesss! Lots and lots of flowers in the dead of winter! This is the first year I've had a large number of winter-bloomers to be getting spikes from in fall, tho I had quite a few spikes in spring last year as well.

About the climate -- this summer was cool, but most summers here are hottttt and humiddddd. We are consistently about 10 degrees hotter than you, and every storm in the gulf sends moisture here. You may miss a few of those, but don't you get humidity from the lake?

I know we don't get the stifling humidity that you get, but we do have a lot of very humid days(altho not this summer). The closer you are to Lake Michigan, the somewhat cooler you get. It kind of acts as an air conditioner in the summer, yet due to the lakes temperature in the winter being warmer than the actual air temps, it makes it a tad warmer near the lake. Hence the lake effect snows. I am on the border of this phenomenon, so I don't really see or feel the effects the lake has on things. I don't think we miss too many of the gulf storms, I think whatever you get, we get also, maybe just to a lesser degree.

[kmarch]

I'd not read the Gordon book. It's an interesting point he makes. I notice that he increases the temperature range. I suspect doing so increases the diurnal temperature. What do you think? The more we delve into the specifics of these theories, the more I am inclined to think all three theories are all the same (!!!?!?!?!).

Oh and don't worry about tieing the diurnal theory around my neck. I didn't take it negatively at all and figured exactly what you said, that you mentioned it and me together because I am usually the one singing that song. I just wanted to make sure I was not taking credit for ideas that did not originate with me.

Finally I wonder if it is worth considering the differences between phal species and hybrids. I pose this question as an example: Are some phal hybrids complex enough that their needs in this regard begin to significantly depart form the needs of their species parents?

[mehitabel]

Originally Posted by kmarch

I'd not read the Gordon book. It's an interesting point he makes. I notice that he increases the temperature range. I suspect doing so increases the diurnal temperature. What do you think? The more we delve into the specifics of these theories, the more I am inclined to think all three theories are all the same (!!!?!?!?!)....

Finally I wonder if it is worth considering the differences between phal species and hybrids. I pose this question as an example: Are some phal hybrids complex enough that their needs in this regard begin to significantly depart form the needs of their species parents?

I do think all three theories are (mostly) the same. That's sort of what I meant in talking about "confoundings". The idea of excessive warmth inhibiting spiking is interesting.

About the species and complex hybrids thing:

I made up a chart of the months the different species tend to bloom. There are two clusters: A winter-spring blooming cluster and a second summer-fall blooming cluster. The winter bloomers bloom from app Jan thru app July. These are the ones spiking now. Except for one species, they all have a relatively thin, soft texture. The summer bloomers bloom from app July-Aug thru about December. Amboinensis and equestris are the only species that bloom in both time periods. For the rest of the species, it's either-or.

What you say is true, the blooming period will depend on the species ancestry, and some hybrids *could be* so complex that there would be no dominant tendency.

Except for this: that from the beginning, roundness has been the preferred phal shape for awarded phals, and always bigger flowers have been desired. Big and round comes primarily from P. amabilis the ancestor of what I call Big Whites, and definitely a winter bloomer.

Many of the intensely-colored species are in the second cluster, and have short spikes of smaller, star-shaped flowers with a very thick, often waxy texture. So do the species that impart intensity of color to the offspring. *As soon as breeders try to improve the shape, or create larger flowers, they start introducing a Big White parent.* (ie they bring in P amabilis in the form of awarded Big Whites with perfect shape)

So we always come back to the fact that to get flowers that are desirable to most people instead of just to a few collectors, and that get awards, the hybrid has to have a lot one of the big, white or pink, fall-spiking winter-blooming species. The hybrids that don't have any of this ancestry always have smaller flowers with pointier segments-- collector's phals.

Take yellows, eg. The rule for yellows is, the bigger the yellow, the paler the color and the thinner the texture (because it has more Big White parentage and less of the pointy, waxy, yellow-producing species).

For multifloras, the multitude of flowers and the branching habit comes in part from equestris (clouds of tiny flowers) and partly from a couple of fall-spiking species with branching tendencies. I think equestris is why some of the multifloras tend to bloom twice a year. (Equestris is one of only two species that are in both the winter- and summer-blooming clusters). But even these have quite a bit of Big White in them, including amabilis to perfect the shape and make the flowers a little larger. eg Nobby's Amy, a multi-flora with smallish, perfectly shaped round flowers -- 28% equestris parentage, 25% amabilis and 50% other fall spiking species.

I think what happens with yellows is that *some* yellows spike in spring, and some *others* spike in fall. Some get their yellow from P amboinensis, which can spike or bloom in any of the 12 months. Some get their yellow from P venosa, a fall bloomer. And some get yellow from both ambo and venosa. My guess would be the phals that spike in spring have less of the Big White than the fall-blooming ones. I could check this with the information I have, but just haven't done it. I might do it tomorrow, and then post back about it.

The influence of heredity in the breeding of all orchids is *the* most fascinating subject of all to me. There are a number of articles on breeding for different colors of phals at Bedford Orchids, and some at Phoenix Orchids. Anyone who's interested in how different qualities have been bred into phals would probably enjoy them.

If I were younger, I would want to try my hand at breeding, see if I could master the art.

[Ray]

Dr. Yin-Tung Wang of Texas A&M is the guy who took the long-standing "two weeks of cool nights" to "2- to 3 weeks of overall lower average temperatures" - I think he decided about 15°F difference was the trigger.

(A side note: 80's in Houston IS a cooler period!)

I also recall that plants white/pink/purple color range tend to be more temperature-responsive than orange/yellow color range (most likely reflecting geographic distribution of the species, as you guys mentioned), but as the modern hybrids get more and more complex, that generalization gets less and less applicable.

[Ron]

Dr. Yin-Tung Wang of Texas A&M is the guy who took the long-standing "two weeks of cool nights" to "2- to 3 weeks of overall lower average temperatures" - I think he decided about 15°F difference was the trigger.

Hi Ray. I have heard this theory a lot and in my area in summer it seems more reasonably as we get very hot weather in summer but a drop of at least 10 deg at night.
another factor often forgotten is very good culture to grow the plants quickly so they can be mature enough to trigger the flower spikes.
Interesting
Ron

[kmarch]

To clarify, when Ron says 10 degrees I believe he means 10C, not F as Ronis in Australia where we use C regularly. A drop of 10C = a drop of 18F.

[FLBob]

I tend to feel that growing in temps sub-80's F my Phals will be more apt to begin to want to flower. With temps over 80 the plants seems content to grow leaves and roots. Regardless of the change between day time and night time temp.
Since I grow outdoors in near tropic conditions I have learned that all my phal hybrids will be in flower during the spring. I don't even start looking for spikes until we've had a few weeks where the daytime highs are in the 70's F.

The folks that grow indoors in near constant temps and light, but still flower Phals really throw a monkey wrench at theories as to what triggers a Phal to flower. Sometimes I wonder if plants just don't have an internal clock.They grow for a while then they flower, then they grow some more.

[mehitabel]

Nope! Can't find anything different in the ancestry of yellows that spike spring or fall. Hmmmm. I guess they just spike when they feel like it

[lmartiny]

I'm newer and I grow outside. I find they are seasonal. Mostly Spring time. I think they have a time of year they will bloom. Like everything else. But there is always an exception. We are still very hot. (unseasonably) but I've got a Phal spike coming along.

[Brooke]

I think it is all genetics triggering bloom time. If the different species bloom in different seasons, the hybrids will take their cue from whatever gene tells them it is their season to bloom IF their cultural requirements are met.

Brooke

[mytwogirls]

Originally Posted by FLBob

The folks that grow indoors in near constant temps and light, but still flower Phals really throw a monkey wrench at theories as to what triggers a Phal to flower. Sometimes I wonder if plants just don't have an internal clock.They grow for a while then they flower, then they grow some more.

I hope this is true. I have nothing really intelligent to add here, but I have been doing a LOT of reading on phals and most of the reading says if the plant is healthy and happy it will flower when it is ready.

[shaz]

I don't know anything about growing outside but I think with growing indoors it's a matter of the plant being ready and happy - and if it is it will flower