Deflasking Disas

 

Disa seed can successfully be sown on damp, boiled sphagnum moss, and at one time this was the preferred method of propagating Disas from seed. A detailed description of the procedure may be found in the excellent booklet written by Dr. Louis Vogelpoel, now out of print. A copy can be viewed at (http://www.disas.com/louis_vogelpoel.htm ). However, much quicker growth is possible using a sterile nutrient agar medium, i.e. “flasking”. Seedlings live a pampered life in the flask: humidity is 100%, no diseases or pests, and no need for them even to use photosynthesis, since the medium contains lots of sugar as an energy source, in addition to the usual mineral nutrients.

Seedlings are generally ready for deflasking after 6-12 months. They should be at least 3-5 cm high, be sturdy and have well-developed roots before being removed from the flask. Vigorous, deep green, solid-looking seedlings deflask well; weedy and pale ones are likely to succumb within a few weeks of being deflasked. Occasionally a flask will become contaminated with a mold or other growth before the seedlings have reached optimal size for deflasking, but they can sometimes be saved if care is exercised. Spring is the best time to deflask, since this is the time of year when Disas grow most vigorously.

The plants should gently be removed from the flask. If the agar gel is soft enough, it may be possible to invert the flask and shake the gel and plants loose. Remove all loose gel and separate the plants from each other as far as possible. Roots can get very entangled and a few are bound to get broken. It is vital to remove all traces of the gel from the roots, otherwise the sugar present serves as a perfect site for encouraging unwelcome microorganisms. I use a jet of cold water from a garden pressure sprayer to flush the gel from the roots. Support the roots during this process to avoid breakage. Also, avoid bruising the stems and leaves, as this leaves them vulnerable to infection. When all the gel is off, weak old roots can be trimmed off, leaving only plump, strong new roots. Yellowing old leaves should be cut off, and long, straggly leaves trimmed back to around 3-5 cm. I then soak the seedlings in a solution which contains fungicide (10 drops of Subdue concentrate per litre) and either a Dynagro product called KLN which is supposed to lessen transplant shock, or 2-4 mL (1 tsp) of a kelp extract/vitamin B1 formulation. Work quickly with the plants and don’t leave them lying around in a warm room for more than a few minutes - these seedlings are very susceptible to dehydration at this stage, and low humidity is dangerous for them.

The seedlings then go into a community pot loosely packed with damp sphagnum or a Supersphag:Perlite mix. If you use sphagnum, it is easier to plant them if the top inch or two of the moss is chopped into short lengths. Other airy, moist media also work well. Seedlings like company in these pots - 10 to 12 in a 8 cm square pot is not unusual. The seedlings should be watered thoroughly with a dilute (e.g. one tenth strength) high nitrogen fertilizer (30:10:10, 20:20:20, 10:5:5 or similar).

For the first few weeks it is important to conserve humidity around their leaves, and to give the seedlings more subdued light than mature Disas. If you have just a few community pots, place them in oversized Ziploc bags and blow into the bags to inflate them before sealing them.

  Ziploc.jpg (40196 bytes)   (Click on the thumbnail for a full-sized picture.)

Plastic sandwich bags and the bottoms of clear plastic soda bottles (inverted) can also be used as mini-greenhouses. If you have more pots, a 2 x 1 foot flat with a clear plastic top is excellent. After a day or two, if exterior conditions are not too hot and dry, you can begin to gradually lift the plastic covering to harden off the seedlings. Try to do this during cool conditions, and be on the lookout for signs of dehydration. On the other hand, if the Disas are completely closed in with no air movement, you are likely to have serious problems with damping off. In that case, apply a fungicide (Subdue, Captan, Cleary’s 3336, Aliette) and provide more air movement. Alternate fertilizer applications with thorough watering to leach out mineral salts.

Within 2-3 weeks, community pots can be treated as for mature plants. Within a few months from deflasking, the seedlings should have developed strong new roots right the way to the bottom of the pots, and they may be crowding each other in the community pots. They can then be individually potted into small pots (~5 cm square). After a year or so in these pots, they should be ready for full-sized pots (~8 cm square). If deflasking is done in spring and the plants receive good treatment, a few may bloom as early as the summer of the following year.

The foregoing routine works for me, but other growers have their own procedures. Find out how they do things too, and be prepared to experiment to find a method that works for you.