Rock Wool Medium

[DirtyCoconuts]

I wanted to dig up this thread the other day and i forgot too

i notice that loose cubes dry out more fully as opposed to a lot of the other media i have played with.

I have made a bunch of tubes of gutter guard and filled them with all manner of medium for different plants. For my bulbos that climb i used straight cubes. I have others with mixes of leca and cubes, coir and cubes, leca and coal and coir and i have a few with perlite too.

one day i was watering and i noticed the cubes looked really dry so i checked a bunch and all the ones with the cubes visible appeared very dry. it had been a few days and i wanted more than just looking at them so i watered and weighed 10 tubes. weighed them again the next day and so on for a week.

THe pure cubes gained the most weight (no surprise as they hold the most water) and lost the most weight. so i was curious if they were still moist at all and opened on of the tubes and the cubes were super dry, like from the bag dry.

I have always insisted that leca never gets fully dry in South Florida but i think the grocubes open structure and packing them loose exposes more surface area and allows for some really dry medium if you arent witchful.

i added some punky old pieces of broken basket wood into those mounts to see if it will act as a reservior of sorts.


just some anecdotal gro cube observations

[WaterWitchin]

I've noticed that in my setup as well, although I can't imagine anything drying out in your sauna environment.

I've had several containers that had moved from my layering technique to mixed at the top third to half of the container. This happens when dogs tip over the pots to drink from the water tray (fertilizer is tasty water). Also a granddaughter who likes to search for frogs and sometimes tips over a pot. I just scooped up the LECA and Grodan cubes and chucked them back into the top of pot.

When we go into a less humid environment, called fall and winter, I noticed the ones that had cubes on top overall dried out much faster than the layered ones, both cubes and LECA, and have re-done top part to be layered again. I always have a couple layers or so of LECA as the top layer. It seems to better protect the moisture and slow down the evaporation, but the cubes layer beneath keeps the top layer of LECA from drying out.

Never really thought about it before DC, but good anecdotal stuff!

[spes1959@gmail.com]

I'm interested in your Cattleya experiment. could you tell me how many days do you water the plants with mix 50 50?

[Georg Luiz Barth]

Hi guys.... 4 months after the last report, how is the evolution of the experiments in favor of improving the moisture distribution inside the s/h pot with reservoir, using leca and rockwool? I would appreciate any comments, thanks.

[WaterWitchin]

Well, my last report was October 2020. I'm still doing the layering technique, roughly 25-30% rock wool cubes, the rest LECA. I noticed better moisture retention right away, so just kept doing it and never looked back. The first two pictures I showed, I've already had to repot them after blooming.

Faster growth than before, more blooms. Anything that's needed repotting now gets the same treatment. Since January of 2021, no more experimenting, just doing it.

Here's the paph species from first pictures that's more than doubled in size, now starting to colonize, from December 2021



A Phrag grande from first pictures blooming in August 2021

[Georg Luiz Barth]

Great news, thanks for the feedback WaterWitchin. Basically I'm following the same guideline....but I just started 15 days ago. I had to adjust my watering cycle every other day with 25ppmN (using only Leca in s/h pots with reservoir) to water every five days with 75ppmN using Leca mixed with rock wool (80/20). Here in the south of Brazil we are practically in autumn and the temperatures are a little lower. I noticed that the dry line became more difficult to be observed, due to a better distribution of moisture inside the pot. I need to pay attention to the watering time, because I'm still unsure about the transition. My fear is that the roots may eventually be more prone to rot, but for now everything seems to be fine.

[Ray]

I have several plants in a mixture of RWC & LECA - some are mixed, others are layered, some S/H, others "traditional" culture without a reservoir.

They have been on my back porch all winter and all are doing well. I can't see much of a difference.

[Georg Luiz Barth]

Perfect Ray. It appears that the balanced use of leca and rockwool cubes fills an important gap in "certain" growing conditions with inorganic media. Mainly, when it is not possible to control the low humidity of the environment in which we grow our orchids.

[estación seca]

George, what are typical day/night temperatures in winter where you live? I visited many towns in Minas Gerais and Bahia in June but was not farther south.

[Georg Luiz Barth]

Originally Posted by estación seca

George, what are typical day/night temperatures in winter where you live? I visited many towns in Minas Gerais and Bahia in June but was not farther south.

Minas Gerais is located in the southeastern region of Brazil and Bahia in the northeast region. These are states with higher average temperatures than Santa Catarina, which is in the south of the country. I live in the city of Criciúma, south of Santa Catarina, about 25 km from the sea. Here winter and summer tend to be more defined in terms of temperature. In summer you can easily reach 38-39 degrees centigrade and in winter 10 degrees centigrade. In higher places it is possible to reach 0 degrees or a little less, with the possibility of some snowfall under ideal conditions. Belo Horizonte, capital of the State of Minas Gerais, is 1300 km from Florianópolis, capital of Santa Catarina. Salvador, capital of Bahia, is 2700 km from Florianópolis. Travel distance by car in highway.