I need a bit of input about Phrags...

[abax]

and winter. I'm trying to decide if I should remove the
clay saucers of rain water that I set most of my Phrags.
in for the summer. My greenhouse humidity is running
in the 90s consistently without the humidifiers on. I have
plenty of air movement and LED lights on the Phrags., but
am still seeing a bit of erwinia. Dragon's Blood is taking
care of the erwinia, but it seems to me that sitting in water
with that kind of humidity isn't such a good idea. I'd love
some opinions and experiences that might help me resolve
my indecision.

 

[gonewild]

What is the air temperature?
What is the temperature of the media?

 

[Rick]

For the Phrags I have semi hydro (or water in trays), they stay in SH year round.

A few, newer things, that I haven't bothered to repot to SH are still in pots with regular potting mix, but get watered every day.

I have a couple of big plants (a big multi growth Phrag caricinum, and Phrag longifolium) in SH that occasionally see erwinia when they are breaking out new growths. For the last year I usually haven't been bothering with any treatments, and the infected leaf falls off with a good new growth intact. But sometimes the older growth keeps making new growths and loosing leaves before its even tried to bloom, so I end up with a bunch of started new growths, but no bloom for that older growth.

The lemon juice has made a difference in the last few months in this issue. The plants have been making new growths without loosing the older growths and the older growths are getting much bigger, and starting to thicken up at the bases suggesting they are about to spike.

How much N are you applying when you feed Angela? I would continue to knock it down to under 5ppm if you're not already there yet, and touch up with the lemon juice. You might also consider grinding up a couple of aspirin tablets/gallon, and adding that.

 

[abax]

Air temp. is running mid-sixties at night to close to eighty
if the sun is out...mid-seventies with just the LED lights
on. I use Orchiata and I'm guessing the media temps.
are high sixties/low seventies. Stakes feel slightly cool
to the touch with all the air movement in the gh.

I use K-Lite fertilizer about twice a month at the recommended dosage and will take the frequency down
as we move into the winter months. I don't usually fertilize at all in Dec., Jan., Feb.

Rick, have you ever tried running Phrags. without sitting
in water in the winter? My humidity at 11:56 pm is 94%
and foggy in there. Seems a bit much moisture to me
even with two 52" ceiling fans and small fan blowing slightly over the plants 24/7.

What do you think Lance? Please forgive the questions, but I'm
still learning on slippers and come across a conundrum from time to
time.

 

[Clark]

Stop using the sprayer.
Get bucket and water from bottom up. St. Peter sits for 30-60 minutes.
Mine don't sit in trays of water.

November was like clockwork for erwinia. Nothing for three years.
Go ahead and cringe, all the 'chids share the same bath. Just once though.
YMMV.

 

[eteson]

Erwinia and winter?
"My" erwinia comes to visit my phags only if night temperatures are over 68-70F. If night temperature is about 60F I even set the fog or mist system a few mintues by the end of the afternoon.

 

[Secundino]

94% at midnight should de OK.
If you feel the plants are too wet while sitting in water, don't let them sit in water in the colder months. With such a high humidity they will be happy.

Btw, you are sure the hygrometers work well? You wrote about a humidity consistently in the 90s, that made me wonder.

 

[NYEric]

If you can maintain the humidity take them out of the water; keep track of the roots.

 

[gonewild]

What do you think Lance? Please forgive the questions, but I'm
still learning on slippers and come across a conundrum from time to
time.

90-100% humidity at night is very normal in the natural environment for phrags. With good air circulation in a green house it is actually very good at 94%.

Your temps and humidity in the greenhouse are not a problem for leaving them in water. Under your conditions your plants should grow year round, maybe even better growth during the cooler winter that the hot summer. Just keep doing what you are doing. Avoid wetting the foliage on dark days and you are good to go.

 

[abax]

Clark, I water the Phrags. by hand with rainwater. I make a considerable effort to never ever get water on the plants. My Phrags.
are sitting in individual clay saucers, not in a tray of water.

Secundino, I have three hygrometers in different parts of the greenhouse and all seem to agree on humidity. The only time my humidity comes down is on a very sunny day and the louvers open and the exhaust fan comes on.
Today the humidity got down to about 65% when the
louvers and exhaust fan were running. In that situation,
it's either let the plants burn up or let the humidity go down. I had three humidifiers going and wet down the
concrete floor. The Phrags. were sitting in rainwater with
the LEDs on. Whaddayou do in that situation?

 

[Rick]

Rick, have you ever tried running Phrags. without sitting
in water in the winter? My humidity at 11:56 pm is 94%
and foggy in there. Seems a bit much moisture to me
even with two 52" ceiling fans and small fan blowing slightly over the plants 24/7.

Yes and no. I have 10 or so species and some are SH and some aren't. The long petaled types like caudatum which seem to have the most issues with erwinia have gone from SH to dryer, and now probably going back to SH.

My big pearcei (which I've had since 2002) has been in a tray since I got it (year round) and gets sprayed down from the top. It rarely ever has an erwinia problem.

I'm sure this is heresy, but I don't think watering and humidity have much to do with erwinia.

 

[gonewild]

Yes and no. I have 10 or so species and some are SH and some aren't. The long petaled types like caudatum which seem to have the most issues with erwinia have gone from SH to dryer, and now probably going back to SH.

My big pearcei (which I've had since 2002) has been in a tray since I got it (year round) and gets sprayed down from the top. It rarely ever has an erwinia problem.

I'm sure this is heresy, but I don't think watering and humidity have much to do with erwinia.

P. cadatum is soaking wet most of the time in nature. I've never see a wild one with rot.

 

[cnycharles]

A wet problem likely is because of not enough oxygen in the water. Wet media causing problems likely same reason. In previous work greenhouses often leaky roofs or water lines dripping on plants didn't rot them like you'd see in orchid or other pots if you kept watering soaked and undrained media, likely because moving water was bringing oxygen with it
I don't know answer to your first question; I'd be nervous with that high humidity that I could see as fog but defer opinion other than I might use a tray where you could aerate water

 

[abax]

I assume the rainwater is aerated since I empty and fill
the saucers every day, but possibly I'm wrong about that.
All the Phrags. are in clay pots with holes around the sides so again I assume there is sufficient air movement through the media. However, my take on this is only
assumptions.

When you say aerate the water in a tray, are you suggesting something like an aquarium bubbler...I have
forgotten what those little dohickies are actually called.

 

[Rick]

Oxygen levels in clean water is mostly a matter of temperature and barometric pressure.

If you want (or don't want) oxygen levels to go below saturation then you need to stop biology.

So changing water frequently will keep bacterial counts down in the trays, but really doesn't do much for the moisture in the pots.

Reducing bacteria food is another way of controlling bacteria. But a tiny amount goes a long way.

You have to cut the nutrient load to almost nothing to get to oligotrophic conditions in the pot. Something most of us aren't willing to do.

Plants (including orchids) have immune systems to combat disease. Most of the NPK supplementation we expose are plants to is counter to developing a well functioning immune system.

Erwinia is everywhere in the environment ready to take advantage of stressed / compromised plants. Obviously the trick is to figure out what the weak link is to get the plant to take care of itself instead of responding defensively with surgery and chemicals.

For phrags I'm leaning (these days) towards water withholding as an artificial stressor that compounds the problem. Things that boost the immune system are salycilic acid, organic acids (like citrate and malate), and a high Ca;K ratio in the tissues.

 

[tomkalina]

Hi Angela,

I've been following this thread for awhile now and thought I'd jump in to let you know how we are currently growing Phrags. at Fox Valley.

1)We no longer grow Phrags with pots sitting in trays of water. We found we had better growth by top watering every other day; summer and winter. This practice assures a good supply of O2 in the root zone.

2) We no longer use Orchiata. After a two year long test period, I was not happy with the results in terms of root growth and went back to a standard seedling grade fir bark mix - ratio 8-1-1 (bark-large perlite- #3 size charcoal). The plants are growing much better with that change. Not sure why it works for some who use it, but it didn't work well for us.

3) We fertilize every other day, alternating K-Lite, MSU for RO and Peter's 30-10-10. We add whichever fertilizer we are using to 50 gal of RO +5 gal of Chicago water (for it's micro-nutrients) and aim for a TDS of 200 ppm. We have a 55 gal plastic barrel which we pump out of when we are fertilizing. This gives us about 70 ppm N2. On days we are not fertilizing, we flush the pots with straight Chicago water, which has a TDS around 220 ppm.

4) Our gh summer night temps are whatever the night temps are outdoors; rarely as high as 80F, but normally around 65-70F. Summer day temps are dependent upon the outdoor humidity because we use an evaporative cooler, so normally 72-82F. In winter we have night temps of 60-62 F and day temps of 70F + whatever the sun provides with minimal shading; sometimes as high as 78F.

5) We use 60% Aluminet shade cloth in summer, and light levels are around1,000-1,500 fc because the gh is shaded partially (20%) by surrounding shade trees. We remove the shade cloth on the 15th October and apply shade paint to give us a light level initially of 1,800-2,200 fc. Obviously, this light level decreases significantly as the sun's angle of incidence decreases. All readings taken at noon on a sunny day.

6) We use only plastic pots. Clay pots are fine for most orchids, but I think if your gh temp at night is in the low 60's and you have vigorous air movement, because of evaporation clay pots get a lot cooler than the low 60's and no slipper orchid likes cold roots.

7) Make sure you temper your irrigation water in winter. I lost a good amount of seedlings a couple of years ago using cold (48F) water out of the barrel. I now use an aquarium heater in the barrel in winter and heat the water to 68-70F before irrigation.

Sorry this is so long, but there are some things that absolutely have to be controlled if you're to optimize Phrag. growth..... It's not the only way to grow Phrags., but it's the way we grow them. Hope this will help.......

 

[Secundino]

Oh! W.O.W.

 

[abax]

My rainwater is greenhouse temp. because I bring it in in
gallon jugs and let them sit for a couple of days before using it. My impression from various sources indicated that Phrags. enjoyed cooler temps. than Paphs.; not cold, but cooler. Perhaps that's incorrect. My summer/winter
temps. are within a couple of degrees of your's. I don't
fertilize nearly so much nor do I find Orchiata disagreeable. I'll have to think about the plastic pots. I
don't like them and find that potting media sours much
faster. Hmmm...Thank you Tom. You've given me some
things to think over and perhaps reconsider.

 

[Silverwhisp]

1)We no longer grow Phrags with pots sitting in trays of water. We found we had better growth by top watering every other day; summer and winter. This practice assures a good supply of O2 in the root zone.

....

3) We fertilize every other day, alternating K-Lite, MSU for RO and Peter's 30-10-10. We add whichever fertilizer we are using to 50 gal of RO +5 gal of Chicago water (for it's micro-nutrients) and aim for a TDS of 200 ppm. We have a 55 gal plastic barrel which we pump out of when we are fertilizing. This gives us about 70 ppm N2. On days we are not fertilizing, we flush the pots with straight Chicago water, which has a TDS around 220 ppm.

....

Hello Tom,

So, what you are saying is that every day, summer and winter, your Phrags get either plain water or fertilizer water, correct?

Is the fertilizer solution always around 70 ppm N2?

Does this regimen hold true for all types of Phrags? Kovachii vs. caudatum, e.g.

Thanks-
Patricia