Lack of moisture on the surface of the pot with lecca

[WaterWitchin]

Originally Posted by Clawhammer

I have moss on top of all my s/h pots, which I water daily.

What kind of moss Clayhammer?

---------- Post added at 08:56 AM ---------- Previous post was at 08:55 AM ----------

And it grows directly on the LECA?

[Clawhammer]

Originally Posted by WaterWitchin

What kind of moss Clayhammer?

---------- Post added at 08:56 AM ---------- Previous post was at 08:55 AM ----------

And it grows directly on the LECA?

Yup, on the leca.

[IMG]Untitled by Eric, on Flickr[/IMG]

[IMG]Untitled by Eric, on Flickr[/IMG]

[IMG]Untitled by Eric, on Flickr[/IMG]

[WaterWitchin]

Where can I get some of this moss? Like the kind that grows back in the woods?

[Clawhammer]

Originally Posted by WaterWitchin

Where can I get some of this moss? Like the kind that grows back in the woods?

It grows on everything in my grow room (including the outside basement walls that are cooler than the daytime temps). I have top prune moss monthly, especially in the mounted area or the pots I keep constantly moist. 80% humidity plus high light and you'll have more than you know what to do with. Live moss does have a nice symbiotic relationship with orchid roots, its like an extra layer of velamen. It can start engulfing the plant if it is not kept under control.

[Grim Tuesday]

So I've mixed grodan rockwool cubes into several of my pots and all seems well. They definitely slow or eliminate the formation of a dry top layer. I also read about top dressing with non-wicking material (e.g. "pea gravel" or approximately LECA shaped, irregular but smooth pieces of marble and quartz, $4 for 40 lbs at Lowes) and tried that too. The idea being that it slows down evaporation from the top layer and makes sure any new roots hit a clean rock, rather than a salty LECA ball when they originate. It seems to perform as advertised and the price is right.

So then I tried rockwool AND pea gravel, because two good things must make a great thing, right? And that's why I'm posting in this thread, because I started noticing some spidery fungus forming right under the top layer of a plant. And the question is: Have I made the top layer too evenly moist? Is that even possible? Or do I need to work on other things, like temperature and airflow? This pot was in a fish tank, so airflow was certainly lacking.

[Clawhammer]

Love the pea gravel idea

[Georg Luiz Barth]

I also put some of my phalaenopsis into a mixture of Leca and rockwool (+ - 80%/20%). In the catleyas I only put pieces of wool on the surface. I noticed a visual improvement in the distribution of moisture inside the pot s/h and the dry line was much less apparent. The relative humidity of the air currently in my growing environment is in the range of 30% - 35% and the temperature around 30 degrees Celsius. As all the growing medium in s/h is more humid, I will change the irrigation with fertilization from 25ppmN, every other day, to 50ppmN every three or four days. Watering will continue to be done using the method of filling the pots with the nutrient solution from top to bottom, keeping the reservoir filled to the level of the drains.

[Grim Tuesday]

Originally Posted by Clawhammer

Love the pea gravel idea

I certainly can't take any credit for originating it, I heard about it from the Orchid Room on YouTube. It has the major practical advantage of weighing down the leca so it doesn't float out when flushing (I have Ikea leca and I'd say about 70% it is lighter than water). It also helps keep the plants stable, and is incredibly cheap. Something I thing might be interesting would be a full mix of rockwool, leca, and non-wicking gravel, with the idea being that the rockwool provides little pockets of moisture, and the gravel provides little pockets of dryness, for plants who don't like too much moisture, but also don't like to be dry.


It also has the theoretical advantage of slowing evaporation, not just adding water to the system like rockwool, so the cooling effect of evaporation should be lower. And it looks nicer and is easier to push around than plastic rings.

I did recently try putting some of it at the bottom of the pot to stabilize everything and make the pot less top heavy but that was an honestly terrible idea, as water no longer wicks up from it, so the reservoir is effectively shrunk. No idea why I didn't realize this at the time I was potting them... I had to re-pot those plants a week later, and the gravel is no fun to separate from the leca haha.