Pierre Pujol on Unflasking Cymbidium Seedlings

In flask, plants do not close their pores (stomata) because the humidity is high that they will not dehydrate. The process of “hardening off” allows them to practice opening and closing their pores. This means opening slightly the stopper of the flask for a few days prior to deflasking, allowing an exchange of air within the flask.

Rinse agar media off of roots as gently as possible (I soak mine in warm water, rinse with a strong spray of water several times untill most of the gel is off the roots), handle the plantlets by the leaves, not the roots. Sanitize plants with Physan or similar before laying out to dry (let roots become white before potting up).

Plug trays with stabilized coir media simpily potting up, as there are no roots that need to be untangled, but community pots can be successful. Plants will still be easily dehydrated, because their stomata are not yet efficiently opening and closing. Keep humidity high by loosely enclosing plants with clear plastic. Watering consistently at this stage is key, keeping humidity up no matter which media you are using. Keep good air movement around the plant, and never allow plant to sit in water.

Keep PH at around 6. Start with fertilizer at 50 ppm, go to 100 ppm, then up to 300 ppm in the Summer. For the plant´s first season, try to push the growth before plant enters Winter dormancy. Bulb maturity depends on the number of sun hours at 60 to 80 degrees F. A plant with no winter (tropics, greenhouse) grows twice as fast!

Newly transplanted seedlings need lower light levels than adult plants. After the first year, give them as much light as they can take without burning.

~Paula Shiu

Published online on February 15, 2016