To grow an orchid from seed can be a complicated process, but once mastered can provide a thrilling sense of satisfaction.
The plant to be used as pod parent should be well established with good root growth in fresh medium before seed bearing is risked. To bear a seed pod is hard on the mother plant and often jeopardizes its life. The planned end-result should be worth this risk.
The preferred method of collecting pollen is to use a sharpened glass rod or a platinum wire that can be quickly sterilized and cooled.
After pollination the plant should be dried out a bit and removed to a more sheltered part of the greenhouse.
The seed-bearing plant should be treated moderately, but with particular care in watering to avoid chilling at night
Fertility of the seed may be determined microscopically, although there are other means of determination. Fertile seed, under the microscope, appears browner than infertile seed and reveals dark blurs.
It is best to plant seed immediately. Absolute cleanliness should be the rule in planting. Hands and tools should be washed in a 20 per cent Clorox solution. If possible, seed should also be sterilized, as contamination is invariably easier to prevent than to cure.
Seed may be sterilized with a degree of success in 3 per cent solution of hydrogen peroxide. Most growers prefer calcium hypochlorite, 10 gm. to 140 cc. of distilled water, filtered. Seed may be exposed to this solution for fifteen to twenty minutes without harm, but a longer exposure will yellow the seed. Rapid whirling or shaking of the container holding seeds and sterilizing agent will make certain that the solution washes over each seed.
Antiseptic containers should be provided after sterilization is completed. Test tubes are satisfactory in a number of respects. Medium is placed in the tubes and the tubes laid on their side to provide more planting surface.. Erlenmeyer flasks provide generous planting surfaces. Whatever the container, it should have been sterilized in a pressure cooker or autoclave for thirty minutes at fifteen pounds pressure.
There is wide variation in the kinds of planting enclosures used, the choice often being determined by practical considerations. It is still advisable, however, to spray lightly if an ordinary room is used. Fungi spores travel on dust particles floating in the air, and spraying causes them to fall to the floor.
The planting medium must next be provided. A wide choice of media is available. Orchid magazines carry names of firms that sell the necessary chemicals as well as prepared products. Some of the media available, such as Difco Bacto Orchid Agar, require only the addition of water.
The materials are now ready for the final operation of 'planting.' A platinum needle or loop, which may be readily sterilized in flame, is ideal, but a long-handled spoon, a pipette, or an eye-dropper are all satisfactory. Sterilized seed is floated in a vial containing a bit of distilled water. The seeds (so tiny that they have the appearance of powder) are taken up with the tool and scattered over the planting surface in the flask or tube.
A rolled stopper of cotton (flamed to kill fungus) should have been kept in the mouth of the flask, being removed only long enough to permit the seed to be placed inside
After the seed has been introduced, the cotton stopper should again be flamed over a Bunsen burner and the mouth of the flask and the stopper wrapped lightly with paper. The flasks should be kept at an even temperature of not lower than 65 F nor higher than 80 F. A temperature of somewhat above the 65 F minimum is most desirable.
The flasks should be kept by themselves in some kind of an enclosure (a Wardian case in the greenhouse is excellent) where they may be protected from sun and excessive moisture and moved as little as possible. This stage of culture will last from eight months to over a year.
When incipient roots are one quarter of an inch long, the seedlings are ready for repotting.
Congratulations! The orchidist has succeeded in raising an orchid from seed - no easy feat! |
