Propagating orchids by division, through offshoots, or by raising seedlings is easily within the realm of most home growers. The method you choose depends on the type of orchid and on how much time you want to devote to the process.
The easiest method of creating new orchids is by division. When you divide a plant, you’ll end up with one or more new plants identical to the parent. The techniques for dividing differ, depending on the type of orchid.
- Sympodial division
- Most orchids with a sympodial growth habit can be divided as you might divide an iris, to produce more plants of the same kind. Use a sharp, sterile knife to cut through the rhizome at a point that leaves three to five pseudo bulbs or stems per division. Then carefully pull apart the mass of roots and re-pot each division. Strong divisions such as these will establish themselves so rapidly that flowers may be borne on the next year’s growth.
Don’t throwaway orchid stems or old “back bulbs” (those pseudo bulbs, taken from the rear of the plant, that no longer bear leaves); many times they can be induced to grow new shoots simply by placing them in empty pots. When growth appears, you can plant them. Plants produced in this way generally require 3 to 5 years to mature.
Clumps of paphiopedilums are easily divided into more specimens. Rather than cut the rhizome, use your fingers to break it with a twist. Leave three growths to a division. Old stems of dendrobiums can be cut into small sections and placed on moist sphagnum moss to encourage plant-lets to develop. Plant-lets produced naturally on the plant can be separated from the stem and potted as soon as roots form.
- Monopodial division
- Monopodial orchids can also be propagated by amateurs. The side shoots that develop on many monopodial orchids can be removed and re-potted once they have started their own roots. Tall-growing monopodials that make many aerial roots may be increased by decapitation: simply cut off the upper portion of the plant and plant it, with some of its trailing aerial roots, in planting mix. The lower portion will usually develop a new growing point.
Sometimes plantlets called keikis form on flower spikes, especially on phalaenopsis and the canes of epidendrums. Once their aerial roots are 1 to 2 inches long, cut or break off and pot these striplings; then enclose them, pot and all, in a plastic bag until you see evidence of vigorous growth.
Another method of division is worth mentioning, even though it is not one for the home grower. Sooner or later, you will hear or read the term meristem culture, which describes a specialized method of rapidly increasing the number of choice plants-especially those of a scarce new cultivar. From the plant’s growing tip, the meristem (the tissues at the end of a shoot containing embryonic, or undifferentiated, cells) is removed and cultured in a nutrient solution. There it reproduces itself into masses of undifferentiated tissue. Later this material is divided into small clumps; these are set in flasks of growing media, within which they develop into seedling-size plants identical to the parent plant. Hybrids reproduced in this manner may be termed mericlones.
Raising Seedlings from Flasks
Growing orchids from seed is a time-consuming process best left to experienced specialists. However, you can buy flasks of small seedling plants all ready to be transferred to “community pots.” This way you get the pleasure of seeing your own unique seedlings produce their first flowers, but without going through the laboratory procedures necessary for germinating the seeds.
Many orchid suppliers offer seedlings grown in flasks containing as many as 200 (but more commonly, 25 to 40) tiny plants. These plant-lets are considered ready to come out of the flask when they are about 1/2 inch high; usually they are this size when you buy a flask. Better results can be obtained if the plant-lets are bigger, however-at least 1 to 3 inches tall.
- Starting a community pot
- A community pot is simply a more advanced “nursery” than the flask for baby seedlings; at this point they are so small-and numerous-as to make potting them individually impractical. Before removing seedlings from their flask for potting, you should assemble all of the materials you will need for the operation. A number of 3- to 5-inch pots (well scrubbed and dipped in boiling water or a 5-percent bleach solution, if they have been used before) should be soaked in water for several hours so that they will not extract any water from the potting mix. When the pots are ready for use, add a potting mixture of seedling-grade fir bark combined with material you have screened out of a coarser grade. Pack the mix tightly into the pot and water it.
To remove the seedlings from the flask, pour 1/2 cup of room-temperature water into it. Swirl the flask; then pour out the loosened seedlings into a shallow bowl. Repeat this process until all seedlings are out.
Planting the seedlings is the easiest part of the operation. Punch holes in the potting mixture with a pencil and set several of the plants in place in their new home in the pot.
Seedlings in their first community pot require a humid location and a relatively constant temperature, in the 70° to 80°F (21° to 27°C) range. A greenhouse satisfies their needs easily. Lacking this, you can buy or easily make a small glass case to house the pots. Even a packing box with a glass pane over the top may be suitable. Whatever you use, the seedlings should be placed in a bright but not sunny spot.
Never allow the potting mixture to dry out, but remember that soggy conditions are just as unsatisfactory. You will probably have to water daily-and early enough so that the foliage will be dry by twilight, in order to thwart diseases. On sunny days the seedlings will also benefit from a fine misting during the day again, early enough for the leaves to dry out before dusk. Open the seedlings’ enclosure for an hour or two each day to allow air to circulate around the plants.
- Time to transplant
- It will take about a year (depending on the species grown) before your seedlings are ready for transplanting. If you started with 1/2-inch seedlings, put three to six plants into a clean 3-inch pot in the same type of potting mix. Give them more light and some weak fertilizer once a month.
If you began with larger seedlings, the plants are ready for individual pots whenever they start to crowd one another. Transplant them into small-grade fir bark in 2- or 3-inch containers. A final transplanting is necessary after about one more year, at which time they should go into individual 5-inch pots in medium grade fir bark. Most plants will flower while in these pots.
If this whole procedure seems too lengthy to you, you can buy orchids in the 2-or 3-inch-pot stage. These sturdy youngsters will have passed the most vulnerable time of their lives and will be about 3 years old (that is, starting from seed); they should be about ready for their third transplanting. Depending on the vigor of the orchids, a fourth potting may be needed to bring them up to flowering size.
Orchids from Seed
Some plants taken from wild or vegetative divisions are often found in typical collections. Most will be plants raised from seed of parents in cultivation or perhaps mericlones of good orchids. The classic formula for choosing the parents is to cross a good flower with a good flower. Rubbish crossed with rubbish will probably produce flowers of a similar quality. Typically, a hybridized will mate a good flower with another which has that quality but may have a weakness in an area where the other parent is strong.
To make the cross, do it at about the time the seed parent’s flower is a quarter to a third through its normal life. That is, if the flower would normally last about six weeks, do it when it has been open two weeks.
First, carefully remove the pollinia (pollen grains bound together in waxy masses) from the flower of the seed parent and take it away. Use a toothpick or sharpened match. Next, using a different toothpick, remove the pollinia from the pollen parent. It should be bright and yellow and waxy although some genera have dark pollinia. Press it well into the sticky stigmatic surface (if it is not fluid and sticky the flower may not be receptive) of the seed bearer. The stigma is the sticky cavity found on the under-surface of the organ formed by the union of the stamen, style and stigma of the flower. Do not be disappointed if the flower dries up and drops off. Even if a seed capsule forms the seed may not be viable. Attempted crosses between widely unrelated genera are likely to fail.
If a seed capsule forms, the time taken for it to ripen is most likely to be between six months to a year, but will be a lot less in some genera. The capsule should be removed immediately if it starts to yellow. You can sow the seed yourself -it has been done on a kitchen sink – but it is usually a laboratory procedure. Alternatively, the seed can be sent to one of the professional laboratories undertaking this work for hobbyists. Find out whether they prefer the dry seed or the capsule before it has split. If the seed is viable you should receive the seedlings back, ready to deflask, in six to 18 months.