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Orchid flasking

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Orchid Flasking

Growing Orchids by John Marvin

Orchid flasking is a procedure in which orchids can be grown from seeds. Orchid flasking is necessary for producing orchid seedlings since orchid seeds do not have endosperm and usually require a symbiotic mycorrhizal fungus to germinate. There are two different techniques for flasking Symbiotic germination and Asymbiotic germination. Symbiotic germination requires the isolation of an mycorrhizal fungus which is added to agar to grow the seeds. Asymbiotic germination just uses nutrients that the seed requires to grow with.


  1. Sterile environment: An environment without fungal spores such as a glove box or over steaming water.
  2. Seed pods
  3. Flask can be any glass bottle
  4. Cap (if used tape the sides of the container with water proof bandages or aluminum foil) to flask or rubber stopper (must have a hole on the top which is stuffed with cotton)
  5. Stainless steel rod bent into a hoop at the end
  6. Spray bottle set on mist
  7. Medium (What seeds are planted on)
  8. Sterilizing agent: Bleach, Sodium hypochlorite, or ethanol/isopropanol alcohol can be used.


Preparing flaskEdit

For flasking, all material must be sterilized before they can be used. This is done by using a pressure cooker.

  1. First prepare the medium inside a flask. Make sure it is at least 25.4 mm (about 1 inch) high. If you are planning sow the seeds and re-plant into another flask use 12.7 mm of medium (about ½ inch) Do not be tempted to make a thin layer of medium.
  2. Put the lid on the flask and put the flask into the pressure cooker. Pour about 2 inches of water into the cooker and cook the flask for 15 minutes @ 15 psi. A microwave can also be used to instead of a pressure cooker but a dish of water must be added under the flask so it does not boil over.
  3. Place all tools and the flask inside glove box (knife, bleach, container of water). Spray the glove box with a mist of 10% bleach solution all over the inside of the case and wait five minutes for the solution to kill of contaminants.

Seed sowingEdit

Once the flask are prepared, the seeds can be sown in two different ways. Seeds can take from several months to several years to germinate.

Green-pod methodEdit

The Green-pod method is a method of sewing orchid seeds before the seed pod is fully mature. Make sure the seed capsule is not broken.

  1. Put the seed capsule into the glove box. If glove box is not available it can be done in area with steam such as over boiling water.
  2. Sterilize the seed capsule by washing it in a 5% bleach solution or a 1:4 solution of 60-70% Sodium hypochlorite (NaClO) for at least 10 to 15 minutes. During the wash, scrub the outside of the capsule with a toothbrush.
  3. After the wash, rinse the seed capsule in distilled water.
  4. Cut open the seed pod with a sterile knife or a spatula.
  5. use spatula or a steel rod with a ring to spread seeds over the medium. Seeds can also be washed from the seedpod with distilled water and pipetted into the mix to eliminate fibrous material.
  6. Seal the flask

Dry pod methodEdit

The dry pod method is used to sow dry seed or seed pods with cracks on them. It is best to sow as soon as possible after harvest. But seeds can be kept for several weeks and may gradually lose viability.

  1. Add the seeds into a 50 ml bottle
  2. Creat and add 15ml of a solution of 3.5 - 7 gm of Calcium Hypochlorite per 100ml of water to the bottle and one drop of detergent
  3. Shake for 5 minutes and filter the solution with a funnel and filter paper
  4. Filter two more times with sterile water and move bottle (with the filter paper covering it) and the funnel into the glove box.
  5. Open the flask and use a sterilized spatula(5% bleach solution or a 1:4 solution of 60-70% Sodium hypochlorite (NaClO) for at least 10 to 15 minutes) and spread the seeds from the filter paper onto the flask.
  6. Seal the flask


If the medium dries out due to air exchange or the plants are overcrowding, you may want to consider transplanting the protocorms. Start by sterilizing tools used in transplanting by leaving them in container of 10% bleach solution for 5-10 minutes also move the flask inside a glove box and mist the area with bleach. Prepare one or several flask with medium. Distilled water can be used to remove all protocorms from the flask. If several protocorms are desired to be transplanted use a steel rod with a loop. When transplanting leave space between individual seeds.

Caring for flaskEdit

Orchid flask should be placed under fluorescent lights for 8 hours per day. The flask must be kept in an area with 70 to 75°F. Do not try to simulate daylight hours because it will stress the seeds. Seeds should begin to grow in four to six weeks regularly. Certain seeds can take up to one year to germinate. Some plants require different conditions to germinate such as darkness (Paphiopedilum ciliolare).

Contamination of the flask usually may show up in the first week. If the flask is contaminated, it is best to discard all content inside and restart.


When the plants has more than three roots you may de-flask them.

  1. Place the flask into warm water for five to ten minutes to melt the jelly.
  2. Open the jar and pour the seedling out and place the plants into a shallow dish of water and use a stick to carefully tease the jelly off of the roots. If the flask has a bottled neck the seedlings can be removed by rinsing the bottle with water.
  3. Prepare a tray with compost and moisten it with some water. Make several depressions in the tray and carefully place the plant in. Cover the roots of the plant. If roots break apply fungicide. Plants can also be grown in sphangnum moss. It is best not to fertilize them for two weeks
  4. Keep the plants in 70% shade. Place a cover over the tray and slowly open within a four week period it to adjust the plants to the environments humidity.

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