Observations in Growing Cyp acaule (lengthy)

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Abgeschickt von Michael Vaughn am 22 Oktober, 2004 um 00:12:57

After several years of attempting to grow C. acaule and many failures I seem to have finally found a method in which C. acaule thrive.

My first two years in attempting to grow this tempermental species were daunting failures. I tried the loose woodland mix my bletillas seemed to enjoy, but even mixed with copious amounts of perlite this proved to be too rich and mucky for the acaule to handle. The following I tried a more sterile approach. Using a soiless expanded clay media and watering with vinegar enriched distilled water had somewhat better results than the previous year, but wide swings in root moisture and lack of nutrients saw slow often lagging growth. This year, alongside my successful method, I tried a mixture of coconut husk chips, Coir, and expanded clay as an aggregate. This was a miserable failure and the plant refused to make any roots. The other cypripediums grew in this mix with roots growing well, but developed strong nutrient deficiencies.

Alongside this years failed coconut husk chip experiment I gathered all the information presented from sources such as Vermont Lady Slipper Company and Dr. Philip Cribbs book on Cyps. and combined that with what I was witnessing in woodlands near my college. Entering the acaule habitat I collected buckets of white pine duff and a fair amount of the redish brown acidic sand that lay a few inches below the soil surface. Philip Cribb touched upon these materials in his book. However to ensure an ample air supply around the roots I worked this pine duff through a fine window screen to remove the finer particles of detritus. I feel this is an absolute must when growing acaule in pot culture because this removed material is finer than peat and even when slighty damp can be pressed into a solid ball in the hands. This left me with roughly two thirds the volume of duff that I originally started with, but those two-thirds were light and fluggy and did not compacted even when saturated.

With my materials in hand I created three seperate pots each slightly different in either size or amendments. In the large 10" green plastic pot I filled the bottom inch with sifted perlite mixed with enough of the acidic sand to dirty it. The remainder of the pot was filled with the pure sifted pine duff with about 3/4-1" of soil covering the roots and crown. The second pot was a smaller 6" pot filled with a roughly equal mix of duff and perlite with a small amount of the acidic sand mixed directly into the media. The final pot was growing a smaller acaule so I went with a 4" square pot filled with the same perlite and duff mix as above. As per Vermont Lady Slipper Company's suggestion all pots were watered with distilled water mixed with cider vinegar at a rate of 2 oz. per gallon. This acidifies the soil and provides the Cyp with an organic acid that seems to be strongly beneficial in providing them a nutrient source. I have done some reading that acaule may be able to use these acids as a carbon source much like the chlorophyll lacking Corallorhiza orchids.

As for the results. The 4" pot proved to be too small and thus not stable enough in its moisture content. The cyp grew and thrived, but a missed watering by a few days resulted in dead root tips. I later moved this to a larger pot. In both the other pots the Cyps grew strongly. The roots were clean and white showing no signs of fungal or bacteria problems. The cider vinegar reduced the pH enough to eliminate most soil microbes and has had the added benefit of keeping the soil in the same condition with little or no evidence of decay. However all pots showed the development of very mild nutrient deficiencies evident by subtle intervienal chlorosis. Interestingly the cyp with access to a bottom layer of pure sand and perlite developed these symptoms less noticably. I theorize this deficiency have resulted from one or more of the following areas:

-Transition into a new soil means plants must adapt their metabolisms slightly and might take one or more seasons to occur
-The vinegar mixture is too strong and has dropped the pH just a hair too far below optimum levels
-The acidic sand provides the necessary silica needed for nitrogen fixation and acaule might naturally need higher amounts
-Artificial fertilizer may be necessary

Next year I will set one cyp aside from the others and feed it with a weak, calcium free, fertilizer mixture to see if that remedies the mild problem. The only other curiousity is that one bud has developed a root halfway up from the base that punctured through the protective bud sheath. I posted this in the forum asking for opinions, but it seems to be just a random oddity. I also feel it important to mention that these cyps were placed into this new mix in spring before their new root growth. I have since added one other cyp into this potting method, but did so in mid-season and all growth tips died. While the roots themselves have remained healthy it seems that active root tips can not handle sudden changes in soil chemistry.

Finally on a side note I will mention other terrestrial orchid results in the 50/50 blend of pine duff and perlite. This does not relate to growing acaule per se, but I feel it gives a broader sense of the nature of orchid roots and how they react towards soil types. Basically added to give readers some comparable data. Not watered with vinegar water unless mentioned.

Bletilla striata- Excellent succes. Roots grew strongly and no nutrient deficiencies developed.

Goodyera pubescens- Similar in habitat to acaule so grew strongly in this mix. Also watered with vinegar water.

Ludisia discolor- Although a terrestrial it seemed against this mix. No rotting occured, but roots refused to grow into the mix.

Cyp. X Andrewsii, & both var. of parviflorum- Placed into this mix while dormant the roots have grown well. Therefore texture wise this is an excellent blend. However, the growing season will be the deciding factor if these cyps can handle growing in a strongly acidic soil ammended with oyster shells.

Cyp. formosanum- Much to my surprise hated this mix. New roots would grow briefly then the tips would rot. As I posted in a previou thread I can not fully understand why this occured. I somewhat believe there were other variables that caused this failure. I may try again next year.

Spiranthes odorata- Grew very well in this mix. Bloomed for the first time in two years when given this mix and more sunlight.


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