- By Wolfgang H Bandisch
- Posted April 14, 2016
A Beginner's Guide to growing Orchids from Seed: Green Seed Flasking
It can take a very long time for a seed capsule to ripen. There are some statistics on the gestation periods however, I found that these are unreliable as there are several factors to be considered, temperature, light and humidity being the three most variable from country to country. Ripening periods vary considerable also within the same genus and I have found that e.g. Dendrobium bifalce capsules would fully mature within about 3 months while Dendrobium lasianthera will take at least 6-7 months and Dendrobium nindii as much as 10-11 months. Spathoglottis seed capsules may take as little as 30 days to ripen. Capsules of some Bulbophyllum species may need more than 12 months.
It is now a matter of judgement and only experience with fully matured seed capsules can be used as a guide as to when the seed inside the capsule is fully matured. Do not rely on colour change of the capsule. The date of pollination must be noted on a label to be able to make an educated guess. As a rough estimate two thirds of the time needed for the capsule to fully mature are considered the time required for the seed inside the capsule to ripen. This means that seed can be flasked in some cases 3-4 months earlier and that is a great saving.
Another important advantage of green seed flasking over dry seed flasking is the fact that the seed in the undisturbed closed capsule is sterile and there is no need to sterilize the seed prior to flasking. The seed is fresh and full of vigor and cannot be damaged by the chemicals used for the sterilization process.
The procedure of green seed flasking is quite similar to dry seed flasking and most of the materials and bits and pieces as described in my last article are required with the exception of the seed sterilizing solution and the syringe and needles. We need however, have to acquire a couple of other items, namely a toothbrush, a scalpel or razor, some kind of spirit burner or open flame and a pair of forceps.
Green Seed Flasking Process
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Prepare your flasks, motherflask medium and sterilize as per the dry seed flasking beginner's guide.
Write down in your notebook everything you do. On the page where you have the name of the orchid's seed you will be flasking, species or hybrid, write down that this time the capsule was green.
Get a baby food jar, punch a hole in the center of the lid, make a wick out of some cotton material and insert this wick into the hole. The wick should be long enough to touch the bottom of the inside jar. Fill half the jar with methylated spirit. Place this inside the laminar flow cabinet.
Place scalpel and forceps inside the cabinet.
Start up your laminar flow cabinet. Turn on the clean air filter. The filter should run for not less than half an hour before you start working. If the cabinet is equipped with a UV light, this should also be switched on at the same time. Beware of the UV light. Never look into the light. Permanent damage to your eyes can be the result.
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Prepare one sterilizing solution from bleach. Use the 1000 ml graduated container and pour in 200 ml bleach (e.g. Snowite) and add 500 ml distilled water. Normal tap water is also okay. If normal tap water is used let it run for a minute or so in case there is any debris in the pipe and use it then. Fill the spray bottle with this mixture and thoroughly spray the inside of the laminar flow cabinet - but not the clean air filter - until it is soaking wet. Place the cotton dish washing cloth in the center of the cabinet and spray it with the bleach solution.
Decant a small amount of this solution in a deep dish, large enough to stand one of the flasks inside. Decant another quantity in an empty flask or glass and place toothbrush and forceps inside. Put dish and the glass inside the cabinet.
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When the medium has turned solid you are ready to start work. Cut small pieces of self-adhesive tape and stick them on the flasks. Write the identification number of the seed on the tape.
Switch off UV light. Put on the dishwashing gloves and sit in front of the cabinet. Spray the inside of the cabinet, the cloth and both gloved hands thoroughly with the bleach solution.
Get your assistant to pass the flasks to you by first placing them into the deep dish. You take them out form the dish and spray them thoroughly with the bleach solution. You are now working in a sterile environment. Keep it sterile, use the bleach solution liberally and avoid sudden movements. Never cross your arms, learn to work from left to right or vice versa, whatever is convenient.
Take the green capsule and carefully remove all dried floral parts and dirt (if any). Place capsule in the container with the toothbrush and leave for 5-10 minutes. Light burner. Remove capsule and brush it thoroughly with the toothbrush to remove all traces of dirt and dust. Rinse capsule in bleach solution and if needed repeat cleaning with the toothbrush. Hold capsule with the forceps and flame it.
Unscrew the lids of those flasks you will use for this lot of seed but leave lid on the flask. Flame scalpel blade and while holding the capsule with the forceps cut the capsule either in half or with larger capsules it is sufficient to cut out a segment like a little window. Holding the capsule with the forceps in one hand remove the flask lid with the other and shake a little of the seed into the flask. Put down capsule and close the lid. Repeat as required. Spray flask especially under the closed lid.
Store flasks in a dry place as described before. Observe flasks daily for any sign of contamination. Write down the date of germination in the notebook and also if and when contamination occurred and its colour.
Within a week or sometimes a little later you will be able to observe germination and the swelling of the seeds. They turn green and continue to grow, eventually forming tiny leaves and roots. Soon the flask will become very crowded and it will be time to replate.