Micranthum

[dodidoki]

Its not the Calcium thats the problem. Its the carbonate, anything over pH 6.5 to 7 and you will start to get problems with nutrient avaiability-especially Iron. I think you would do well to start off micranthum at pH 6 and add a little dolomite if your pH drifts down too much. Say to 5.5. You should check media pH every six months or so until you get a ''feel'' for what going on in the mix. You should totally forget the ''Limestone Factor'' and try duplicating thier habitat conditions by adding lots of lime. Its obvious that if they can do well in sphagnum, they need ACIDIC conditions at the roots. Alkalinity always causes trouble. For example cactus growers are well aware that trying to grow Ariocarpus species (which grow in nothing but limestone chips in Mexico) in an alkaline media (greater than pH 6.5), they just won't grow! And its the same with all other ''lime loving plants''- in the pot at least, they need slightly acid conditions if they are to prosper. As dido has said micranthum does well in Kanuma pH 5.5 and bark. Calcium is very important but you can easily over do it with the lime or dolomite or other forms of Calcium carbonate.
If you use Calcium nitrate for your N you should not need to add any other Ca. If you use Ammonium or Urea as your N, your pH will drift down and eventually you will need to add lime. If you look at the ''Limestone Paphs'', they often grow in moss or the remains of moss along with a little clay and humus etc. Moss simply will not grow with more than fractional amounts of carbonate so I believe it should be slightly acid for ALL paphs but with a source of Calcium always present from Calnitrate or bone or Gypsum or whatever.

Very interesting what you wrote, many thanks for that. I think I will try mic in shagnum with living fern. I have a zieckianum and very happy in sphagnum with fern, grow very fast however previously all ziekcs grew very slowly in any media what I tried. I only watered every 3 weeks, in 80-90 % humidity shagnum doesn't dries out at all.( I have some sphagnum stored in greenhouse and always wet however I don't water it at all )

 

[Rick]

I would agree with much of Stones summary.

One thing to note is that alkalinity is not the same as pH and hardness (the measure of Ca and Mg concentration). So if you add things that increase alkalinity like lime or baking soda, the plants will require more of their nitrogen from ammonia rather than nitrate, and you could end up with nitrogen starvation in highly alkaline systems no matter how much nitrate you through on them.

Calcium nitrate (a big component of K-lite) has lots of Ca, but no alkalinity. It's use should be limited to low alkalinity systems to ensure the nitrogen ends up in plants.

Alkalinity if from hydroxide, carbonate and bicarbonate. The addition of pH buffering materials in potting mixes (like horticultural lime and oyster shell) not only supply calcium but supply alkalinity. You also can get a lot of alkalinity from standard surface or well waters.

Micranthum grow very well in low alkalinity systems, but you just need to keep in mind that when you manipulate one item you actually change two or three things.

 

[Rick]

Its the carbonate, anything over pH 6.5 to 7 and you will start to get problems with nutrient avaiability-especially Iron. I think you would do well to start off micranthum at pH 6 and add a little dolomite if your pH drifts down too much. Say to 5.5. You should check media pH every six months or so until you get a ''feel'' for what going on in the mix. You should totally forget the ''Limestone Factor'' and try duplicating thier habitat conditions by adding lots of lime.

I like this section a lot Mike.

There is a big difference between limestone and lime. And most of it revolves around the solubiltiy (or lack thereof) and the release of alkalinity in agriculture lime products.

As noted mosses grow directly on limestone rock, and still require acidic conditions. If you put chunks of limestone in water you would see very little change in pH compared to putting in the equivalent mass in horticultural lime or oyster shell.

In the case of the mosses, the acidity from the moss/algae complex slowly disolves the relatively inert limestone away to provide calcium and a bit of pH control (alkalinity) to keep from getting out of control acidic (like in a spagnum bog).

 

[atlantis]

micranthum dont like calcium too much.

They do well in pure bark and in kanuma for me, now I mix the both, they like to be humid all the time.
Keep them even cooler in winter time.

I was talking last month with a french vendor about P. micranthum because mine has been doing nothing for a looooong time (not dying but not growing) and that was exactly what he told me to do.

He suggested to keep them cold and wet in winter (yes, wet even in winter). He´s using only fine bark, charcoal and perlite as medium, adding some dolomite twice a year (but not including any source of Calcium in the mix).
I can´t tell you anything about the fertilizer regime because I forgot it. Sorry

I´ll try this method for the next season (I have nothing to lose).

I hope this could help you with your tough micranthum.

 

[Rick]

.

He´s using only fine bark, charcoal and perlite as medium, adding some dolomite twice a year (but not including any source of Calcium in the mix).

Dolomite is an excellent source of Calcium. It is a type of limestone, but has a higher percentage (up to 50%) of magnesium in it. If this is actually agricultural pelletized dolomitic lime, it is powdered dolomitic limestone held together with a polymeric binder. It disolves very quickly with watering to boost pH (since it supplies a lot of alkalinity too).

Also what is the nature of the irrigaiotn water used? Unless it is RO or rain water, then it will also have a good amount of calcium in it.

So at this point I don't see any evidence that micranthu do not like calcium.