by Sam Fifer

Orchid flasking is the process of growing orchids from seed. Although the following techniques are not common lab procedures, they have worked fine for me, and should for you too.

If a better way to perform a certain technique is discovered, the procedure will be updated in the appropriate category.

Basics Of Orchid Seed Sowing:
Flasking Case Flasking Tools Flasks Pollination
Pod Times Medium Flask/Medium Sterilization Seed Sterilization
Seed Sowing Replating Flask Care Deflasking
Seedling Care      



There is quite a bit of controversy concerning flasking by amateur growers. The ones opposed to it say that the amateur hasn't a full understanding on hybridizing, thus making inferior crosses. These crosses would then lower the overall quality of orchids in general. The world would be overrun with poor quality plants of questionable parentage.

The other side suggests that many of the very popular crosses were made by such growers, and sometimes purely by accident. Conservationists also argue that the ones that flask species, are actually helping to save certain orchids that are in danger of loosing their natural habitat, or that already have.

Which ever side is correct, flasking is an invaluable learning process in the culture of orchids.

Flasking Case: A flasking case can be as simple, or elaborate as you wish. One can be constructed out of an ordinary box, or plexiglass. The later would be more durable if you plan to do a lot of flasking. Even a fish tank, laid on it's side with some plastic draped over the front will work. There are ready-made glove boxes that can be bought from many firms that are nice, but sometimes expensive.

What I use is a fish tank. I have it laid on it's side, then taken a piece of plexiglass cut to fit the opening, that have arm holes cut in it. I then secure long rubber gloves with duct tape (that stuff is wonderful) to the holes. I also fashioned longer sleeves, so I could reach all the way to the back of the tank. When flasking, the plexiglass top is taped fully to the tank, making an airtight seal. This setup cost me about $50, and has worked very well.

Flasking Tools: These are simple tools that are used in the process of replating, and removing the seedlings from the flask. Thin stainless steel rod, bent into a small hoop, and pounded flat will aid you in the tasks of replating, and deflasking. They can also be used if you need to go into the flask to remove small bits of contaminates. More on that later. Make at least 3-4 of each, so you can be sterilizing one set while using the other.

Besides the replating tools, you will need a small spray bottle for spraying the inside of the box with bleach solution. Two shallow containers for sterilizing, and rinsing tools, a vile for sterilizing and rinsing seed, a pipette, a scalpel, tweezers, toothbrush, and a beaker graduated in milliliters for measuring solutions.

Flasks: There are a number of containers that can be used for sowing, and re-plating. For sowing, I use baby food jars with either rubber stoppers, or Magenta B-Caps...non-vented for sowing seed. This is because to germinate, seeds don't need a gaseous exchange. The media keeps longer, and doesn't dry out. Therefore, you can make a number of mother flasks ahead of time that will be ready when you need to sow seed. I used to use the lids that came with the jars, but found that after 1-2 uses the lids did not work any more, so I went to the types listed above.

For re-plating, again any vessel can be used. Glass is preferable, as it can be sterilized again, and again. Select a container that is big enough for the growth of seedlings. While the sowing flasks don't have to be vented, the re-plate flasks should be. After the protocorms begin to grow, they need a gaseous exchange for photosynthesis to take place effectively. There are many ways to do this. A drilled rubber stopper with cotton stuffed in the hole is the most common. Or, just a simple hole punched in the lid with cotton stuffed in it. The rubber stopper is a better way to go, because mold spores and bacteria have further to travel before entering the flask. There are even specialized tops that can be purchased that have a membrane to let gases pass through.

I have since discovered that juice jars, such as Snapple work very well for replating flasks. Simply punch a hole in the lid with a small nail and then cover both sides with 3M Nexcare™ Active™ circle bandages. These will withstand the heat & moisture of being sterilized in a pressure cooker, while allowing a gaseous exchange.

Pollination: The pollination of orchids is fairly easy once you know what you are looking for. I won't go into crosses here, just the basics of pollination. Hybridizing will be left up to your imagination.

To pollinate a plant, all you need is a pencil, toothpick, or a piece of bamboo, and of course...the flower! Take the "tool" and hook it under the anther cap. Pull it towards you. The cap will fall away, and the pollen will be stuck to the tool. Do the same process on another flower. Take the pollen from the second flower, and press it onto the stigmatic surface of the first flower. Pull away, and the pollen should be stuck in place. If not try again until it sticks. There! You have a pollinated flower! Now all you have to do is wait for the capsule to form.

Pod Times: The time that it takes for seed to ripen in the capsule varies from genera to genera. I have included a table for the various orchid species.

Medium: The medium is what's used to sow the seeds on. It has a number of ingredients to promote growth, and agar to make it jell, so the seeds stay on top of the medium.

There are a number of companies that have ready mixed mediums. All you do is mix in distilled water, and follow the instructions. My favorite companies are:

G&B Orchid Labs...Has a fine general purpose medium. Just add water.
2426 Cherimoya Dr.
Vista, CA 92084

Phyto Technology Labs...Plant media, biochemicals, equipment, growth regulators.
P.O. Box 13481
Shawnee Mission, KS 62282

Sigma Chemical Co....Has everything from media, to equipment.
P.O. Box 14508
St Louis, MO 63178

G&S Labs...Has a very good media. Very high germination rates.
645 Stoddard Lane
Santa Barbara, CA 93108

Flask/Medium Sterilization: The flasks & media need go be sterilized before they can be used. A simple pressure cooker works fine for this. Caution: Using a pressure cooker is potentially dangerous, so fully read manufacturers instructions before using. Prepare the flasking media per instructions, and pour into flasks. How much depends on what type of flask you are preparing. For sowing, 1/2 inch (~12.7 mm) of medium will do. For replate flasks, 1 inch (~25.4 mm) would be better, as the plants will be in these flasks for a longer period and use more of the medium for growth.

Prepare pressure cooker. Pour 1-2 inches (25.4-50.8mm) of water into the bottom of the cooker. Lightly place the lids on the flasks, and set them into the cooker. Secure the lid of the cooker and place on high heat until the pressure relief valve activates. Lower the heat and sterilize for 15 minutes @ 15 psi. Let the cooker cool, or carefully release the pressure and carefully remove the lid. If any of the lids have fallen off the flasks, carefully put them back on and secure them. Remove the flasks from the cooker and let cool. After cooling, they are ready for use.

Seed Sterilization: Once the pod has split or opened, the seed must be assumed to be contaminated. Before it can be sown, it has to be sterilized. To do this, take the seed and place it in a vile, or test tube inside the flasking case. To this add a 5% bleach solution with a drop of dish soap as a wetting agent and agitate continuously for 10 min. Just before the end of this time, decant off the bleach solution and add some sterilized distilled water. Agitate for about 1 min, and then decant once more. Repeat this step one more time. If you don't use a pipette, pour off all but a small amount of water, so you can pour the remaining water and seed into the flask. If a pipette is used, then just leave the water in the vile, and let the seed settle to the bottom. I prefer to use a pipette, as it offers more control.

Seed Sowing: There are two procedures for seed sowing. One is the green-pod method. This is the easiest, as you don't have to sterilize he seed. The second is the dry-pod method, done with the above procedure.

First you must prepare the case for your work. Place all the tools, flasks, and other equipment you will be using during the flasking process inside the case. Spray a fine mist of 10% bleach solution all over the inside of the case, including the flask tops. Let set for 5 min for it to take effect. Using the pipettete, suck up a small amount of seed and some water. Crack open a flask, insert the pipet into the flask without touching the sides. Eject the seed, and water into the flask. Re-stop the flask, and swirl the mixture to spread the seed around. Do the remaining flasks.

Green-pod sowing involves taking a seed capsule that hasn't opened up yet for the sowing process. Put the pod in the glove box, and soak it in the 5% bleach solution for about 5-10 min. Scrub the outside with a toothbrush during this time. Rinse in sterilized distilled water. Slice open the pod, and scrape the seed into the flask. Or you can scrape the seed into a vile of sterilized distilled water, and use a pipette to put the seeds into the flask. This will eliminate much of the fibrous material that's in the pod getting into the flask.

Flask Care: After the flasks have been sown, place them under fluorescent lights for 8 hours per day. Do not try to simulate daylight hours. This creates problems with the growing seed. Seeds should start to green in about 4-6 weeks. Some seed may take longer.

If mold, or other contaminates start to grow, it's best to just throw the contents out. But if the seeds are of particular value, you can go back in and remove the contaminates. Remove the spot, plus 1-2mm surrounding it. Place a drop or two of 5% bleach in the hole that's left. Keep in mind, that every time you go back into the flask, you increase the chance of contamination.

Replating: After the protocorms have reached a workable size, it's time to replate them onto the final medium.

Place inside the case both the mother flasks, and the replate flasks, replating tools, a container of 10% bleach solution, and one of sterilized distilled water, a spray bottle of 10% bleach solution. Place the re-plating tools in the bleach solution, and let soak for 5-10 minutes, then rince them in the distilled water. Remove the stopper from the mother flask, and the flask to receive the replate. Scoop out a small amount of protocorms with one of the clean tools, and place them in the replate flask. Don't spread them too heavy, as the young plants do not do well competing for the same space. Sterilize the tools often to prevent contaminating the replate flasks. I use a new tool for each flask I re-plate. After you are done, replace the stoppers tightly. Place them back under the light, and watch them grow up!

Deflasking: When the plants have grown to 5-6cm, and have 3 or more roots, they can be set out. Once your plants are ready to be removed from the flasks, open them and let them become acclimatized for 24 hours before removing them. The easiest way to remove them may be to break the flasks. This will reduce the chance of damage by being pulled through the neck of the flask. Wrap the flask in a towel, and gently break it open. Gently pull the plants apart and place in a bowl of luke warm water to wash off any bits of glass, and medium. Place the seedlings in a mixture of sphagnum and perlite. Spray with a fungicide/bactericide, such as Physan 20 or RD-20. The seedlings do better if grouped together, so put 5-10 per 3" pot. It's best to not fertilize them right away, but give them a solution of Superthrive for the first week, or two.

Seedling Care: The young plants will take from 3-5 years before their first flowering. To get them to that point, requires special care. To start out, put them in 70% shade for 2-3 weeks, then move to 50% shade for the same time. At this point, they may still need a little more shade than a mature plant, and need to watered more often, as they don't tolerate drought as well as mature plants. You'll just have to experiment with them. I have several Cattleya seedlings that I put in very bright light, and they're doing fine. Fertilize every two weeks with a balanced fertilizer, and repeat spray with a fungicide/bactericide every 3-4 weeks.