Hi,

Thanks for all that great info. I guess "trigger" would be a better
word than forced. Oh and in case anyone is wondering, no I am not
related to Dr. Wang lol....though perhaps in the distant past...?

Cheers,
Xi

Pat Brennan wrote:
Kenni,

You might want to check out some of Dr. Wang (TX A&M) published research on
spiking Phals, it is good stuff. According to his research diurnal temp
change has little to do with spiking phals. My experience is consistent
with his results. While forcing in the summer months my diurnal temp change
will only be 5 to 8 degrees. My experience is also that once spiked, phals
can be grown warmer than 75 degrees without harm to the bud count or
elongating spikes. Where I spike Phals is not the same area or temp of
where I bloom them out.

The diurnal temp change is a bit of a hot button for me. Over a decade ago
I spent a lot of time and money trying to spike phals with diurnal temp
change. After a string of failures and at the suggestion of Dr. Wang I
started working with only high temps. Over a couple of years I developed a
pretty reliable way of spiking most phals. The only other company to try
forcing phals based on the diurnal temp change theory that I know of was
Butterfly in TX. They too failed.

Right now all my phals are naturally spiking. Nov through Feb is my natural
spiking season. The days are short and the sun is low and very weak. The
heaters often runs day and night to maintain 62 degrees. The shutters are
programmed to open at 75 and it has been days since I have seen them open.
This time of year my greenhouses have the smallest diurnal temp change of
the whole year. Today, like yesterday, the difference in greenhouse high
and low temps were 3 to 5 degrees. Sounds like the rest of the week will be
the same, but still the phals will spike.

Pat

"Kenni Judd" wrote in message
...

Diana's understanding is pretty accurate. To the extent of my research,
no one really knows what causes the summer-blooming Phals and Doritis to
initiate spikes. If someone does know, please clue me in!

But for the vast majority of Phals and Dtps. that generally bloom in
winter or early spring, the biggest and most reliable trigger to induce
new inflorescences is a diurnal (day/night) temp change of somewhere
around 12-15F. Adding magnesium to the fertilizer can also help, but I
don't think it will be enough without the temp change. Decreasing hours of
daylight (which happens naturally in fall) also helps, but the temp change
is the "biggie."

One way to "nudge" them is to water at sunset. This cools the roots more
quickly and "fools" them into thinking the temp change is present, if
you're on the borderline. But it carries a big risk of inviting fungal
and bacterial infections.

Now, once you've got this spike started, if it grows up in hot temps,
chances are it's going to be long and leggy, and not produce many
flowers -- very disappointing. That's where that 75F max comes into
play.

Phals with previously-bloomed spikes that are still green can make more
flowers, sometimes from the end, more often from a secondary branching
lower on the stem, and these seem less dependent on temps, but these
bloomings, too, are very disappointing compared to what the plant is
capable of on a good primary blooming.
--
Kenni Judd
Juno Beach Orchids



"Diana Kulaga" wrote in message
. ..

Hi, Xi,

I will answer this only with respect to winter blooming Phalaenopsis.
It's my understanding that Phals in our collections aren't really being
'forced', but rather exposed to conditions that mimic what they would
encounter in nature at a given time of year. I grow outside here in FL,
and the weather naturally cooperates in late October, November and
December by giving the plants the drop in temperature that they require
to spike, without any help from me.

For those growing in greenhouses (and I am no expert on that, having
never experienced greenhouse growing), I expect that they need to
manipulate the diurnal temperature range for these plants.

Now, what I consider 'forcing' would be done by a commercial grower in
order to have blooming plants for shows, etc, during a season when they
would not generally be in flower. I don't see anything wrong with that,
but the plants will likely return to their normal blooming season
afterward, possibly taking a season off to get some rest.

Just my understanding.

Diana