Overwatering issues with s/h?

[smokinjoe1952]

I had thought about using a larger size LECA before Ray posted this, so it might just help. Just out of curiosity, I grabbed a handful of my LECA and measured the diameter, usually at the narrowest point and rounded to the nearest mm.

Here is what I measured: (in mm)

8 8 8 8 9 8 7 13 7 8 9 12 8 8 10 9 7 8 11 9 8 7 10 9 9 10 9 6 9 9 9 11 10 9 8 9 8

Obviously not in the 10-16 mm range as Ray suggests, so I will try a larger LECA at least for Phals.

Maybe larger LECA, along with lower levels of watering, and allowing the reservoir to empty will solve some of my root rot issues.

Although no one has really said, I am assuming the the picture I posted is not how a Phal's roots should look after being in s/h for close to 9 months.

SJ

[AnonYMouse]

Why are you removing the heat pad after only a couple of months?

You are changing variables too frequently. Should you have new roots after 9 months? Depends on what you do during those 9 months.

Don't know where you are (you might have stated) or your growing area ambient temps but I would keep the temps >70°F.

[smokinjoe1952]

Everything I have read on the forum has stated that the heat mat is required only until new roots are formed. I was not sure how long that was. I have since turned the heat mat back on.

I certainly understand how changing variables would stress a plant, but the Phal in the pic has been almost static since last June. My daytime temps are 80 degrees +- 3 degrees. Night temps are 69 +- 3 degrees.

Relative humidity ranges from 60% at night to 50% during the day. Lighting is LED from Fluence bio-engineering and has remained the same (measured and adjusted) brightness with the photo period changing as the seasons change.

Four computer fans run 24/7, but are not blowing directly on the plants. I also have a computer vent fan that runs 3 minutes every 3 hours to prevent mold, mildew, etc. I am not sure I need it because the % humidity doesn't get that high, but figured it can't hurt.

I only use distilled water with the proper pure water fertilizer, but do flush thoroughly with tap water once a month.

The entire setup is in a 4'x1.5'x6' grow chamber.

The only variable that I have changed since last June is to turn the heat mat off.

A lighter watering schedule, keeping the heat mat on and larger diameter leca is what I will try next.

Keep in mind that the perplexing thing about this is that my oncs. Paphs. and Phrags seem to be doing fine. It is just the Phals!

SJ

[Ray]

In general, most phalaenopsis are "hot growers," some species particularly so. They can tolerate more "people friendly" conditions, but very hot and humid is their preference.

Evaporative cooling from the LECA can chill the roots...

[smokinjoe1952]

Ray,

How would I place your comment in the context of my growing conditions?

1. No heat pad needed.

2. Run it only at night, since it may be too much heat with ambient temps. of 80 degrees during the day.

3. Run 24/7

SJ

[estación seca]

Put one of your pots, with medium and water but no plant, on the heat mat. Measure the temperature in the medium on an 80 degree day. If it's under 95 F or so that is great.

The warmer and more humid you grow most Phals the better they do. Higher humidity also leads to more fungus issues. I have found most white-pink hybrids are fine at 40%-60% RH with little fungus trouble.

The jungle growers descended from amboinensis, bellina, violacea and relatives need warmth and high humidity all year. They barely survive low 60s F.

I still think your problem is a combination of:
- Too high a water level in the pots, leading to rotting of lower roots;
- Excessive dryness at the base of the plant where new roots form; and,
- Low temperatures.

[smokinjoe1952]

Thanks for the advice. That will be easy to do, because it is always an 80 degree day in the chamber. I would also now agree with your assessment of my "problems" although after looking at my stash of LECA, I would add needing a larger size to the list.

As you mentioned, I have noticed the roots at the base of the plant usually lose their green tips then decline further.

Would you or do you add a little Sphag. to the top of the LECA to help alleviate the issue? If not, how can the problem be solved?

There is a lot of air circulation in the chamber, so maybe air movement is causing desiccation at relative humidities of 45 - 55%.

SJ

[mtorchid]

Just photographed 3 Phals.

Largest here is in 8" "vanda basket", in LECA with sphag moss on the top. Basket is lined with coconut coir to keep the pebbles in. 20" bloom spike with a second, smaller spike also coming forth as well. I transplanted it from s/h at least two years ago as I was having root issues like the ones being discussed here. The bamboo skewer moisture test is really easy to do with the "basket" slats.

A smaller bloomer in a 4" s/h (gauge pot). If I need to ask someone to water while I'm away, they like the no guess-work of the gauge pots - "water until the gauge comes up half way, don't water again until the gauge drops completely from view" easy!

I have a couple on cork bark, this little guy is starting to send out a spike. I also have several phals in "Ray pots" 2 holes drilled an inch above the bottom but none of them are in bloom right now.

As I mentioned previously, phals that are getting larger don't do well for me in s/h, that's when I transfer them into baskets (which are also impossible to over water of course!) I suppose if, as the plants get big, I transferred them into very large s/h containers, that might alleviate the uneven moisture distribution issue I have. There's only so much room that I have available.

[smokinjoe1952]

Marc

Thanks for posting the pics. I was trying to picture in my mind how you had potted them up.

It looks like that gauge pot is a 4" diameter. Is that correct? In what size pots did you experience problems with larger Phals?

I do have 6", 7" and even a 9" pot, so I may try that once I get a larger plant.

SJ

[mtorchid]

Originally Posted by smokinjoe1952

Marc

Thanks for posting the pics. I was trying to picture in my mind how you had potted them up.

It looks like that gauge pot is a 4" diameter. Is that correct? In what size pots did you experience problems with larger Phals?

I do have 6", 7" and even a 9" pot, so I may try that once I get a larger plant.

SJ

Yes, SJ, that's a 4" gauge pot, the root problems started to happen in pots larger than 4". In my growing conditions the roots near the top and sides of the pots did great, while the interior roots (not visible for monitoring) started rotting.

In hindsight I've wondered if I had let the phals continue to grow in the smaller pots, instead of transplanting them to the next size up, perhaps the roots to LECA ratio would have been such that the moisture would have been absorbed more quickly and thereby less chance of rotting interior roots.

I have had no such problems in s/h with my oncs, catts, brassavola hybrids, just phals. So, while I have no doubts phals will do well in **perfect**, highly-monitored s/h conditions, I do believe in the wisdom that says phals are the least tolerant of any s/h errors, compared to other orchids.