Sphagnum moss and moldy roots??

[Benny@12784]

New here! I have 3 phals in medium bark media from repotme. They’re in a room with a constant temperature between 65-70. Humidity is very low so I have trays and a mini humidifier. The media is constantly drying out (I soak for 10mins once a week). In the past when I’ve used a mix media with sphag and bark, the roots get moldy. Your thoughts? I feel I need the moss to retain some moisture so I don’t lose more roots to dehydration but then when I use the moss, I loss roots due to mold/rot

[estación seca]

Welcome to the Orchid Board!

Do you have time to water more often? That would be the simplest solutuon.

Your temperatures are lower than Phals prefer. Sphagnum stays moist for a long time. In a low humidity room evaporative cooling due to sphagnum drying could drop temperatures even lower.

Have you considered a heat mat to keep them warmer?

[Lil Duck]

You aren’t watering enough, with that low humidity and bark mix soaking once a week won’t cut it, I also agree that those temperatures are far too cold for sphagnum, I keep all my Phalaenopsis on a heat mat set at 81 degrees f. I would either increase watering frequency by running water through the pots 2-3 times a week (depending on pot size) or invest in a heat mat. Another consideration, the mold is not feeding on the roots but is instead feeding on old medium left over from when you purchased them/ last repoted them.

[Benny@12784]

Thank you!! Why type of heat may do you recommend?

[Dusty Ol' Man]

Look up Seedling heat mat on Amazon. There are several available.

[MateoinLosAngeles]

I'm with Lil Duck and Estación here. I grow all my Phals in S/H on heat mats (bought from Amazon).

I do keep my Cattleyas in a bark mix and I don't find them to dry out that quickly, I water once a week and they're "just dry." In the Summer I may need to perhaps increase to 3x weekly. I water very heavily, drenching the media really well, but I never soak them for routine waterings.

Your bark will take some time to "open up" and retain more water, during the first weeks or months after a repotting my plants tend to dry faster. Which is okay with me, I like to water.

You can always try to speed up this "opening" process by drenching the bark with boiling water a couple of times in preparation ahead of your repot.

I stopped using Sphagnum on most of my plants, I only currently have a succulent potted in Sphagnum. It does tend to get soppy.

Something you can try are Grodan Grow Cubes. I mix them with the bark, they're approximately the size of Orchiata Classic or Power, which is the bark that Repotme uses. This bark shouldn't be soaked as it's mixed with beneficial dolomite. The similarity in size makes for a very even particle size which reduces potential water pooling and subsequent rot. They're a great alternative to Sphagnum.

--- Edit

Btw I recommend that whichever route you go, if you just repotted these plants, try to "bite the bullet" instead of rushing to repotting them. I try to abide by the rule "you only get one repot a year."

[orchidman77]

One caveat - I believe using boiling water to open up bark also causes it to break down much faster. As long as you're careful and know when to repot, it shouldn't adversely affect your growing - just your frequency of buying bark.

David

[Dimples]

I'll also add that the general suggestion found online to use ventilated pots (while a good idea for many reasons!) can backfire in some instances. I use very hard bark that doesn't hold onto a lot of moisture, and my growing conditions are warm-hot with high light most of the year, causing my phals to dry out extremely quickly. January - March, I also use seedling heat mats, which further accelerates drying time. Depending on the time of year and the age of the bark, I water every day to every 3rd or 4th day. I like watering, but I'm planning on moving my orchids to pots with fewer ventilation holes when they get repotted. I make my own pots so I'm in control of how much ventilation is added.

I don't know if this applies to your situation, but it's something to think about.

[MateoinLosAngeles]

Originally Posted by orchidman77

One caveat - I believe using boiling water to open up bark also causes it to break down much faster.

Technically, that’s the point. The boiling water is used to somehow fast track the breaking down process, thus making the bark retain more moisture.

It really isn’t an issue with high quality hard barks like Orchiata or Kiwi. The caveat here is that the boiling water drench would inevitably wash off some dolomite, which you might want to keep or deem unnecessary. The dolomite in the bark lasts for about a year and they recommend to just sprinkle some on top after that so begs the question if it’s really worth keeping while sacrificing moisture retention.

This is especially “annoying” as most repotting takes place in late Winter, Spring, and Summer, so technically the first year you have the newer, least moisture retaining bark during the hot months when you would actually like to have it a bit more broken down.

A way around this is using smaller bark. I’ve had a lot of success and convenience using “precision” bark with thinly rooted orchids. Phals would probably do better with “classic”

---------- Post added at 02:28 PM ---------- Previous post was at 02:26 PM ----------

Originally Posted by Dimples

I make my own pots so I'm in control of how much ventilation is added.

I wanna see!

---------- Post added at 02:34 PM ---------- Previous post was at 02:28 PM ----------

Originally Posted by Benny@12784

Thank you!! Why type of heat may do you recommend?

So you can get really fancy with those but I tend to just buy whatever is on sale on Amazon. I have some from SeedFactor and some from AC Infinity. The AC ones lay flatter on the bench which is convenient. Both get the job done.

[Dimples]

MinLA - I use a hot glue gun to melt holes into the sides/bottom of used food containers. Most are 32oz soup containers from Costco. I’ve been meaning to post some photos on here so I’ll add one that shows a homemade pot.