Deflasking of Cypripedium seedlings - Cypripedium.de

How to raise in vitro propagated Cypripedium seedlings to fully established hardy plants for the garden
© Camiel F. de Jong, December 2004
used pure but should be used in mixes. Seramis retains too much water to be
used on its own and Perlite on the other hand dries out too fast and does not
retain nutrients.
A mix that works well for me contains equal parts Seramis, Perlite and Vulca.
However, since Seramis is quite expensive it may be omitted. As Perlite gives off
irritating dust, wear a dust mask during mixing of the substrates and wet them.
The substrates that are used to plant newly deflasked seedlings in must be
completely inorganic. Any organic material present in these mixes may promote
Figure 2. Photographs of individual substrates of mixes used to deflask Cypripedium seedlings.
The scale of the ruler is in centimeters.
growth of molds and consequently loss of seedlings. However, there are two
exceptions: C. acaule and C.arietinum. Seedlings of both species are planted out
in a mix of equal parts coarse river sand and sphagnum peat. The C. arietinum
seedlings seem to prefer more sand in the mix as compared to C. acaule
seedlings. After planting the C. acaule seedlings MUST be watered with water to
which vinegar 1 tablespoon (approximately 30 milliliters) of cider vinegar to 2 L of
water is added to keep the substrate at low pH. To my knowledge, Scott Durkee
of the Vermont Ladyslipper Company was the first to have acknowledged this. It
is absolutely required for the survival of both C. acaule seedlings as well as
mature plants. The plants in containers must be sheltered from rain as the rain
washes out the acids in the substrate, yielding a pH above 4.5. In nature, C.
acaule plants live in soils that are self sustaining acidic having a pH of around
3.5. When the pH rises to above 4.5, water-soaked lesions develop in the leaves
due to pathogens that are subdued at low pH but get a chance at higher pH.
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