How often to water phals.

[tinabee]

Now I have 3 phals. I repotted into S/H. Along with the freebie plant, I repotted a phal I had with just a couple of good roots and some beginning new root regrowth. It was previously in a bark mix, but the new roots were growing horizontally.....not even going down into the media! I was pretty surprised when repotting this particular plant that when I placed it into the S/H pot, the roots automatically pointed downward. The one aerial root is looking a very bright green color after only one day in it's new surroundings.

I got another NOID orchid in the half-price section of the nursery I go to. The reason why I picked it up is because is has a brand new bloom spike just emerging, new roots and the leaves looked great. Poor thing was completely packed in wet, soppy sphag. It would have died within a short period of time had I not repotted it.

My question is.......how often can I water my new phals? I know from what I have read here, you cannot overwater in S/H, but I don't want to overdo it and kill these new plants with too much kindness.

[-k-]

Being new to S/H I can only refer to what I've learned thus far, I observe the reservoir daily to see how low it’s gotten. If after a few days the water level is low, time to water!
During the late afternoon I can actually see the condensation in the pot up around the roots so I know it working (*I think*)

[Ray]

Look at the conditions in the pot before and after watering.

When we water, some of the liquid just pours through, some is absorbed by the medium, and some is held in between the particles by surface tension, "bridging" the gaps.

In a "traditional" medium, because of the irregularities in the sizes and shapes of the particles, some of that bridging water can completely close off the pathways for air flow and gas exchange, and that's what leads to root suffocation, death, and rotting. If we wait a few days, evaporation and absorption by the plant helps get rid of the bridging water, so the roots can breathe again. (I am convinced, by the way, that that is the source of the myth that "orchids have to dry out between waterings". If that was truly the case, neither water culture nor semi-hydroponics would ever work.)

Now consider a fairly uniform LECA medium in S/H culture, where the spaces between the particles are large enough that bridging water does not ever close them off altogether. Just sitting there, the water in the reservoir wicks up to keep the medium moist, and bridging water is insignificant. Then water it and now what is it like? The medium is moist and bridging water is insignificant - in other words, very little has changed!

Don't confuse the frequency of watering and the acclimation of the root system. If you understand that the conditions within a semi-hydro pot are far more constant than that within one used in traditional culture, then you can see that watering frequency is of little consequence. That, however, has nothing to do with whether the roots of the plant are equipped to be in a constantly moist but air environment.

Generally speaking, phalaenopsis plants prefer to have a constant moisture supply, so putting them into S/H culture is typically easy. However, if - because you've been struggling with watering issues (really air management issues) in traditional media - you have kept the plant more on the dry side, then it may need some time to grow new roots tailored to the new environment. That has absolutely nothing to do with watering frequency, so if you hold off to allow the medium to get drier between waterings, you're actually defeating the entire purpose of S/H and stressing the plant more.

[tinabee]

In other words, I'm doing the plant a favor by watering more often than normal. BTW...I posted a thread on FirstRays, so since you so kindly and thoroughly answered my question, you can disregard it.

Thank you for the products I ordered, Ray. I can't wait to see what is going to happen to these test phals long term.

[LouisW]

Yep there is really not way to overwater plants in S/H, but you can underwater by letting the resevoir go dry. Make sure there is always water in the bottom.

[tinabee]

I re-watered my orchids when the reservoir level was halfway between the drainage holes and the bottom of the pot. The pellets could no longer be seen on the sidewalls of the pot like they normally would after watering. Did I rewater at the right time, or should I have waited until even more water was gone from the reservoir?

[orchidholic]

Hello, I really don't want to look dumb, buit what is S/H. It's probably something that I've aleady heard about just not that way???

[tinabee]

Check out the sticky note at the very beginning of this forum, and take a look at Welcome to First Rays LLC . Hopefully, that will give you the info. to get you started. S/H stands for "semi hydroponic".

[Ray]

I prefer NOT to wait for the moisture held against the pot walls to be gone, as that's my indicator that the PrimeAgra is still saturated.

As the water content of the pot is reduced - i.e., taken up by the plant and evaporating - it's the bridging water that is eliminated first, then the absorbed water. Once the absorbed water content has begun to diminish, it means the medium will dry from the top down, exposing the roots to a dry environment and no longer wicking the water and nutrients.