2 new growths lost to rot, change pot?

[SundayGardener]

Hello all,

Wondering if I need to move an Encyclia cochleata to a bigger pot after 2 new growths recently rotted at the base and had to be removed.

It's been in SH for 4 months or longer, and was one of the first that I moved. It took the move well, kept producing new roots, and went on to produce multiple spikes of large blooms, and bloomed for a good 2 months.

Could the moisture level in the pot be too high? It has a good-sized root mass. I've tried to capture this in the pictures attached (which aren't great, but the best I could do). There are pictures also of where I think the growths were removed. Yes, there is some lava rock on top with the hydroton, but it is 90% hydroton.

If it isn't the pot and moisture levels, any ideas why this might have happened after 4-5 months in SH? I haven't seen additional rot, but then it might take longer with the more established growths.

In terms of care, it gets flushed 2x week, under T5HO lights and about 20" away from a southern exposure (old house glass). Temps are 68-72 F, maybe higher when the lights are on, but there's a fan. Humidity ~ 45-55. Kelp max 1x month, Inocuor when I have it 1x month.

[Orchid Whisperer]

That looks like it's staying too wet. I see a lot of algae on those roots. I don't see any indication the pot is too small.

[Ray]

If the plant has been actively growing roots for the four months since moving it to S/H culture, "wet" should not be the issue. I would think "cold", or at least colder, might be.

[SundayGardener]

So, if it is too wet, and yes there is algae, do I let the reservoir dry more and flush less frequently?

In terms of temperature, we have the heat set at 72 which is pretty decadent, but it is an old house with steam heat which is difficult to regulate. I do have a plastic canopy over the shelves with a humidifier. I've looked at heat mats. My concern with that is, how safe are they to leave plugged in all day? I can't leave an unsupervised space heater on, so I'm worried about the mats. (I'm also nervous about the lights, the fans and the humidifier and then adding another electrical device to the mix, because we have shorted out circuits before--old house, with occupants who aren't really savvy about old house electricity, plumbing etc).

The big challenge would be to get a heating mat past the cats...

[SaraJean]

Originally Posted by SundayGardener

The big challenge would be to get a heating mat past the cats...

same!

They make seedling heat mats, for starting veggies and such, that are perfectly safe to leave plugged in. I’ve used these before to get some of my orchids started in s/h and the root growth really took off. I was growing a few pots indoors at the time and my temps were about 70-75, but with the evaporation inside the pot, I’m sure the roots were a bit cooler.

[Ray]

Originally Posted by SundayGardener

So, if it is too wet, and yes there is algae, do I let the reservoir dry more and flush less frequently?

If you have truly gotten the plant's root system converted to growing in Semi-Hydroponics, it cannot be "too wet".

If you are allowing it to dry out between waterings, then you have not converted it, and are merely growing traditionally in an inert medium. There certainly can be a case of "too wet" then.

Excessive algae growth in S/H culture comes about from overfertilization. If you water and fertilizer twice a week, I'd recommend no more than about 25-50 ppm N. 2 divided by the %N on the fertilizer label tells you the teaspoons per gallon for 25 ppm N.

If you have been overdoing it, and especially if the medium is drying out, then you probably have a toxicity issue that is killing the roots, so repotting into fresh LECA is the thing to do.

Originally Posted by SundayGardener

I've looked at heat mats. My concern with that is, how safe are they to leave plugged in all day? I can't leave an unsupervised space heater on, so I'm worried about the mats. (I'm also nervous about the lights, the fans and the humidifier and then adding another electrical device to the mix, because we have shorted out circuits before--old house, with occupants who aren't really savvy about old house electricity, plumbing etc).

The seedling heat mats SaraJean mentioned can be anywhere from only 7 to 13 watts, depending upon the size (and there are certainly bigger ones, too), boost the root zone about 10°F, and are quite safe to use. Personally, I like the ones from Hydrofarm.

[Selmo]

For all of you that hate math. Rays formula 2 divided by the %N is; if you are using 14-14-14, this would be 2/14= 0.142 tablespoons per gallon, 0.142 is just slightly more than a 1/8 of a tablespoon (0.125 tbsps) per gallon of water. Not much, so if you are using more than this, you are just pouring it down the drain. Remember weakly-weekly. Thanks Ray, for this quick method of seeing if you are using enough or too much fertilizer.

[SundayGardener]

I have not been letting it dry out, but I was wondering if I should...However, I do believe that I have been overfertilizing. I have plenty of hydroton on hand, so I can replace what's in the pot with "fresh" hydroton.

I do have a TDS pen, and I tried it for the first time this past weekend, to test the RO water that I buy from a grocery store. The reading from the RO water was much higher than from my tap water, so either the RO water is an imposter or (much more likely) I didn't use the pen correctly. Or our water softener is softening our cold water. I also have a pH pen and once I find it, I'll try that too, because I suspect the pH is too high, at least in my tap water. I've been using RO and distilled for anything in SH.

I'll get some heating mats. I did find from the TDS pen that, if it is accurate, my water is quite chilly. But I go through 30+ gallons a week for the orchids and humidifier, heating the water becomes quite an undertaking. I did do this last winter, but it's a whole process of heating and then letting it cool. And then, it's warm when I water, but anything wet is going to cool right back down again.

[Ray]

S/H does not require purified water, but nothing should ever get softened water!

[Dollythehun]

"heating the water becomes quite an undertaking" I just boil a few cups and add it to my supply before I use it.