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RAISING ORCHIDS FROM FLASK by Brian Milligan

Have you tried deflasking orchids and raising the seedlings to flowering size? It's not as difficult as you may think, provided that you follow one of the accepted procedures, and that you begin with one of the hardier genera. Yes, you may have to wait for four years before you see the fruits (flowers) of your labours. But, by buying several flasks each year and patiently sitting out the initial four-year gestation period, you will thereafter always have seedlings flowering for the first time for the show-bench competition. A word of warning here! Don't become too enthusiastic! Ten flasks each year amounts to at least 400 plants after four years, and one must have room to grow them. Australian dendrobiums and masdevallias don't take too much space, but 400 flowering-sized cymbidiums are another matter entirely.

So where do you obtain your flasks? Various commercial nurseries advertise flasks for sale in Orchids Australia and the Australian Orchid Review or you may find that some members of your own orchid society have sent seed to a commercial flasking service and have a flask or two to spare. Unless you're going commercial, I recommend hobby flasks, which contain up to 15 seedlings. Preferably the seedlings should be 40-50 mm tall, but more importantly the plants should have actively growing roots which reach the bottom of the flask. It's not advisable to deflask your seedlings in winter, as they will grow better in spring when the days are longer and warmer.

There are many different ways of deflasking. The one described gives good results with minimal fuss. Carefully remove the seedlings by inverting and gently shaking the flask. Then wash the roots free of agar gel in a bowl of water at room temperature and allow the plants to dry on a sheet of newspaper for 30-60 minutes. Usually I plant the larger seedlings individually in 2-inch tubes, and the smaller ones in groups of 3-5 plants in tubes of the same size. Watering can be controlled more carefully if pots of the same size are used for all plants.

The choice of potting mix depends on the genus. A mixture of pine bark (5 mm) and river pebbles (4 : 1) is used for dendrobiums and sarcochilus, whereas Sphagnum moss is better for disas and masdevallias. Sieve the bark/pebble mix to remove dust and fine particles, and wash it with boiling water on the day prior to use. Both the bark mix and the moss should be damp, but not excessively wet. Water the newly potted plants to settle the mix. The plants maybe placed in a foam fruit box, which is then covered with a sheet of glass and placed in a cosy location indoors where the seedlings receive good light, but never direct sunlight. Alternatively, put the seedlings in one of those rectangular plastic trays ('flats') used by nurserymen and cover them with vented plastic domes, which are available at the larger nurseries. Keep the air vents closed for the first week or two. Spray the inside of the lid (but not the plants) daily to maintain a high level of humidity. After a couple of weeks open the air vents. Water the plants when the surface of the mix appears dry.

After a month, transfer the tray to a cosy location in your shade-house or glass-house, and in another week or two remove the dome. If at any time the seedlings seem to be damping off as the result of a fungus attack, act immediately. You must spray at once with a fungicide such as Benlate®, Fongarid® or Previcur®. Some growers spray their seedlings periodically with a fungicide as a preventative measure, but others fear that regular spraying helps pathogenic fungi to build up resistance to fungicides. Slugs or snails can eat a tray of seedlings overnight, so sprinkle snail bait nearby on a regular basis. Your tiny seedlings will need careful, regular watering for the first few months, but with care most will survive. When they flower, you will experience a real sense of achievement.

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