Rock Wool Medium

[Ray]

After several months of experimenting, but having had my plants indoors over the winter, I’d have to say I’m leaning away from 100% cubes and more toward a 50/50 mix, or even leaner on the cubes.

I moved them outside for the summer a week ago (but have to reverse that for the next two nights with lows in the low 40’s coming), so once they kick into active growth, I’ll unpot a few and take a look.

[camille1585]

Originally Posted by Ray

After several months of experimenting, but having had my plants indoors over the winter, I’d have to say I’m leaning away from 100% cubes and more toward a 50/50 mix, or even leaner on the cubes.

What have you seen which leads you to lean towards a mix? My plants remain indoors year round, so your winter results could probably be more easily extrapolated to my conditions.

On the grodan101 website they do recommend using the cubes in a mix with leca for more homegenous moisture: "When mixed with non-restrictive media (g. expanded clay balls) a very desirable blend of root aeration and homogenous moisture content can be achieved for extremely vigorous growth and bloom."

[Jmbaum]

I’ve just got in horticultural rock wool sheets that I’ll be lining terracotta pots with (sides and bottom about 1cm) planting in a mix of LECA with a little finer charcoal and pumice. I plan on keeping the plants low in the pot 2-3cm below the rim for the moisture/humidity demanding species. I’ve approximated this with Pleurothallis that was challenged by the lower humidity and moisture gradient of the medium. The results have been phenomenal, with 5 new growths in the 2nd week when previously any new grows would brown in a few days of onset.

[WaterWitchin]

Originally Posted by camille1585

...
On the grodan101 website they do recommend using the cubes in a mix with leca for more homegenous moisture: "When mixed with non-restrictive media (g. expanded clay balls) a very desirable blend of root aeration and homogenous moisture content can be achieved for extremely vigorous growth and bloom."

I'm still doing roughly 25% RWCubes and 75% LECA, as I showed earlier in this thread. A bit more cubes with phrags, paphs, etc. Have been throwing in the cubes each time I repot something, plus have repotted a few that were struggling with the dry line. Now that we're headed into humid season after a long, dry winter, I'm sure it's better with than without the cubes. I'm putting only LECA up to the reservoir holes, then a layer of cubes on top, then sticking in the plant and more layers as I pot it up.

I'm more than happy with the results, plus the sort of layering it in as shown in earlier pictures. I'll probably be following through on same with each plant I repot. I tried a 50/50 mix, but it just seemed too compacted for me and not enough aeration. My goal was to give exactly what Grodan site is saying "a very desirable blend of root aeration and homogenous moisture content."

[Mr.Fakename]

I'm really impressed with this whole LECA/rockwool thing.

In my conditions, 100% cubes doesn't work that great. The bottom ones stay damp, but the top ones quickly dry.
Blending them with LECA gives better results, I guess LECA sucks moisture out of the bottom and redistributes it more efficiently.

Lots of new, very thick and healthy roots, plus leaves and spikes = happy plants, happy me.

[camille1585]

Are all of you using the 1cm cubes or the larger 2cm ones? Grodan has 2 sizes, called cubes and chunks.

[Mr.Fakename]

Originally Posted by camille1585

Are all of you using the 1cm cubes or the larger 2cm ones? Grodan has 2 sizes, called cubes and chunks.

Ha! Well spotted, it says chunks on the bag.

[Jmbaum]

So then in practice the 1cm have the favorable wicking action?

Mr.fakename what’s the RH in the growing area? And how would you describe the airflow? Would be good to establish the thresh hold of where one size of more beneficial than another.

[Mr.Fakename]

RH around the house is sub 30%, but part of my plants are in a heavily planted, semi closed terrarium. I'd say around 80% in here.

Airflow is pretty good in the open air living room, and decent enough in the enclosed terrarium. I tweaked it so I can spray plants at night and the leaves are dry the next morning.

[Jmbaum]

I just put in a wall of rock wool in my terrarium, hoping to get a strong moss Coating and plant some orchids into it as well. I had imagining the wicking in high humidity would be stronger, but really only climbs 15 or so cm to saturate and much less higher up. Rockwool is supposesd to be the quickest for moss growth, so fingers crossed.