Rock Wool Medium

[Ray]

A little bit of data from my experiment:

I had 3 identical 3.5" Square pots I had acquired from Chula orchids



I filled one with Grodan (1cm) mini cubes, one with a 50/50 mix of that and LECA (particles approximately the same size), and later, one with LECA.

They were weighed dry, then I ran water through them from the top, saturating them totally. I waited 15 minutes and repeated that. I waited another 30 minutes for them to drain, then that gave me the initial (t=0) weight.

As a point of reference, the dry weight of the rock wool cubes was 44g and they held 228g of water. The Mix weighed 142g and held 150g water, and the straight LECA weighed 272g and held 26g water. (Note: It is obvious the LECA was not saturated, as prior experiments showed that absorption to be about 20%, not closer to 10%, but I threw that test in there to see how it would fare with "traditional" culture.)

The pots were in my packing room in my garage. Over the time I tested (4 days), the temperature in there ranged from 75° to 81°F, and the RH was fairly steady at 60%-67%.

I weighed the pots at random times, ending about 1 pm Monday 10/26:

[vegetalmatter]

Originally Posted by Ray

Over the time I tested (4 days), the temperature in there ranged from 75° to 81°F

I'm interested in whether or not there is significant difference in evaporative cooling when comparing LECA vs rockwool vs LECA+RW

Am I right in thinking that better water retention = less evaporation = less evaporative cooling?

[Ray]

Originally Posted by vegetalmatter

I'm interested in whether or not there is significant difference in evaporative cooling when comparing LECA vs rockwool vs LECA+RW

Am I right in thinking that better water retention = less evaporation = less evaporative cooling?

That is my thought, as well.

I suppose I could stick a thermometer probe into the middle of the pots of media to check, but it's probably not significant at the moment, with our humidity...