Orchiata contradicting info??

[greenpassion]

Ok. I Was reading a thread on orchiata that was posted recently. Members were posting about how quickly orchiata dries out, and how it doesn't hold/absorb water as much as other bark. So then I found older posts from 2014 that members were saying that it absorbed water MORE than other bark. I'm confused. ??? Does it require more frequent watering, or less?

[orchidsarefun]

There is no easy answer. Orchiata is sold in various sizes - I use the smallest size for moisture loving orchids like zygos and their hybrids and phrags. It seems to hold moisture longer. I use the largest size orchiata for Cattleya and dries quickly. All my phals are in sphagnum as I've found that is what they prefer in my conditions.
Watering epiphytes depends on ambient humidity and temperature, the requirements of the genus and the potting mix ( if any ). For example I mix varying levels of sphagnum with all my orchiata to increase moisture.
First things first - you need to establish the best sized bark for the orchids you grow and go from there. Generally speaking you should only water when the roots appear white or grey. If you can't see roots then you should only water when the weight of the pot is "light" compared to "heavy" just after a thorough watering.

[greenpassion]

I have some of my phals in a mix of orchiata and spag, and some in straight orchiata. I have thus far had continued success with watering them by checking the roots, and holding off until they are silvery/white-as well as how light the pot feels. My concern was wondering if I'm waiting too long to water the ones in straight orchiata. I use the medium size chunks. I do know that due to being on the heat matt, they all tend to dry faster than if I weren't using heat. I am surprised to hear that the smaller size holds moisture longer. You'd think the larger the chunk, the more water it'd hold. Perhaps it's the density in using the smaller size that is the reason?

---------- Post added at 08:18 PM ---------- Previous post was at 08:10 PM ----------

And I know I tend to micro manage, as there are absolutely no signs of distress with any of them! I need to remind myself that if it's not broken there's nothing to fix!

[orchidsarefun]

I have phals outdoors right now, as long as temps aren't consistently below 55f. That includes seedlings and a species phal. Why do you use a heating mat ? I have a violacea indoors, at home temps. I used to use a heating mat for seedlings but stopped years ago - the downside wasn't worth it in terms of humidity and possibly cooking the plants.

[greenpassion]

Using bottom heat is very beneficial for phals. Check out Rays post on bottom heat. As phals are warm growers keeping the root area warm is closer to their natural habitat. I used to think that I only needed to have them on a heat mat in ordwr.to promote root growth in seedlings. I discovered once I moved them all to the mat that their growth and flowering greatly increased.

[orchidsarefun]

Guess my 60+ phals and I will agree to disagree.
Species and hybrids have been so acclimated to varying conditions through selective breeding that most experts would agree that native conditions are broad guidelines only. I've met lots of phal growers from Minnesota that successfully grow phals in much cooler conditions I ever thought possible.

[greenpassion]

I've been growing my phals in temps around 64 in winter, and have been told that those temps are much too cold. I have to say that it's not so in my case as the past 2 years I've had the best growth and flowering ever. I've been growing 7 years now, and have had more success with mine (30) providing bottom heat and staying in low to mid 60's thru winter. I grow indoors only, 17 under ligjts, the rest in an East window.

[camille1585]

Originally Posted by greenpassion

I am surprised to hear that the smaller size holds moisture longer. You'd think the larger the chunk, the more water it'd hold. Perhaps it's the density in using the smaller size that is the reason?

I don't think it's too surprising. Larger chunks of bark won't fit together as closely, and will leave larger gaps of air between the individual chunks. More air pockets = better air circulation, and so drying out the medium at a faster rate. Smaller sized bark won't have as large air pockets between the pieces, it's generally more densely packed in the pot.



About heating mats and Phals, I think there is some confusion between air temperature and root zone temperature. It's true that most hybrid Phals will tolerate much a lower air temperature than species. However, pretty much all Phals appreciate a warm root zone, which explains why Phals gernally don't do as well in S/H culture in cooler climates. The evaporative cooling in S/H makes it a bit too chilly for the roots.

I think that Phals will grow happily without a heat mat (mine do), but I view heat mats as a way to turn the growing conditions from 'well suited' to 'optimal', particularily for warm loving species and seedlings. For a couple years I lived in an apartment which had radiators directly under the windowsill, which kept it warm. I noticed a huge difference in my Phals those 2 winters- they were in active growth far longer than when I didn't have that botton heating.

[orchidsarefun]

In the USA most people have heating/cooling systems that regulate temperatures. I have found that root growth is strongest with phals in Fall when temperatures are cooling, if outdoors. Most of mine are kept under lights in Winter and that raises the ambient temperature.
My Winter house temperature is a constant 70f but does increase if days are sunny.
So a heat mat mat in Winter may be desirable if your house heating temperature is low - which for me would be around 60f. People I met from Minnesota grow phals around that temperature in Winter ( no heat mats ) and then obviously that minimum increases in Summer.
If you have the space and sheltered spot, I recommend that you place your phals outdoors when temperatures are consistently around 60f minimum and bring them indoors when temperatures hit around 55f for a few days. Looking at mine now there is great root growth and most are spiking.

[Ray]

Orchiata does hold less water than many other types of bark, due to its structure and pretreatment. That can be mostly overcome by proper "pre-wetting" with hot water before use, to open up that structure.

Another reason the finer stuff holds more water is the surface-to-volume ratio is greater. Water will only "quickly" penetrate to a certain depth. For the sake of an example, let's says that's 3mm. For a theoretically spherical 6 mm particle (#9 "Classic" is in that vicinity), that means the whole thing can become saturated. For a #7 "Super" particle, at 3/4"-1", it's only a small percentage, so when you fill a pot with either size, that with the smaller bark will contain more water per unit volume.