DE-FLASKING ORCHIDS
by Andre Cleghorn (Flora Laboratories)

(Reproduced here with permission from Andre Cleghorn from The Australian Orchid Review, December 2012-January 2013)


shadehouse
shadehouse
shadehouse

Preparation of materials

  • Sieve some fine pine bark (3-5 mm) to remove any dust and fill a plastic pot with it.
  • Pour boiling water over the bark to sterilise it and remove any remaining dust. Allow it to cool.
  • Fill another pot with medium pine bark (8-10 mm) and sieve and sterilise in the same way with boiling water.
  • If the seedlings are to be planted into used containers, these will have to be disinfected beforehand and for this job I recommend that you soak them in 10% White King* (0.4% sodium hypochlorite) for at least half an hour.
  • Lastly, as far as preparations go, fill the pots or punnets to a quarter of their depth with the coarse pine bark for drainage and then cover with a layer of fine pine bark.

De-flasking procedure

  • Choose plants that have a good root system, but are not too crowded. Fewer large plants are better than many small ones.
  • Fill a container with lukewarm boiled water and carefully hold the clump of the seedlings over the container with the roots only in the water and wash all the agar from the roots.
  • Spread the plants onto paper towelling and allow them to partially dry and harden for about 20 min.
  • Place the seedlings into the prepared pots and fill with mix
  • It is usually better to plant 10-15 seedlings in a punnet or pot (100-150mm) than to individually plant into 25 mm tubes.

Growing On

  • Place the plants into a humid box; a Vates seedling tray and Grow Top are ideal but a foam fruit box covered with a sheet of glass is also suitable.
  • For the first week leave the air vents closed, provide heavy shading and place in a warm position, preferably indoors near a south-facing window.
  • For the first week leave the air vents closed, provide heavy shading and place in a warm position, preferably indoors near a south-facing window.
  • After the first week open the air vents of the humid box but leave under heavy shading. A week later remove the Grow Top and reduce the level of shading. The plants may appear a little stressed with some leaf tip burn, but this is better than allowing them to become too soft and weak under high humidity.
  • After the first week open the air vents of the humid box but leave under heavy shading. A week later remove the Grow Top and reduce the level of shading. The plants may appear a little stressed with some leaf tip burn, but this is better than allowing them to become too soft and weak under high humidity.
  • If you spray the seedlings with an anti-transpirant oil (for example, 'Envy') you can more quickly reduce the humidity because the oil will reduce water loss by the plant's leaves.

Remember

  • Fungicides are not needed unless the seedlings are obviously infected with fungi.
  • Spring and autumn are the best times for de-flasking unless you are able to provide bottom heat during winter or can keep the plants inside your house.
  • Make the changes in humidity, temperature and light intensity from flask to greenhouse for your seedlings as gradual as possible.
  • Water your seedlings with Vitagrow B1. Vitagrow B1 is a combination of auxin plants hormones and Vitamin B1 both which promote root growh. Together they induce rapid root growth which is vital for young plants.