Never grown orchids from seed before?
We regularly get requests for seed from those who enjoy orchids, but have never been introduced to the technical rigors behind their production. For many plants, the seed propagation consists of sticking some seeds
in dirt or sand, and giving them a little heat and moisture. Unfortunately, growing orchids from seed is more technically daunting.
First off, the seeds of orchids are very small- vanishingly small, in fact. Many orchids have seeds that weigh less than a microgram per seed; a 500 milligram aspirin tablet would weigh as much as more than 500,000
of these seeds. Some are much larger, but even at 10 micrograms per seed (a very large orchid seed), that same tablet would weigh as much as 50,000 seeds.
Secondly, because the seeds contain virtually no nutrition (called endosperm), they require external sources of nutrition. In the case of orchid seeds, we provide this in the form of sugar. Like children who prefer
soda to something more nutritious, they also need other elements to their diet, and these are provided in the form of a chemical salt. These are combined with water, and then set into a semi-solid gel (like gelatin)
using a gelling agent produced from seaweed or bacteria, called agar or gellan gum, respectively. However, because this sugar and salt mix is very good at growing bacteria and fungi, it must be sterilized in an
autoclave or a pressure cooker first.
Once the nutrient media is prepared and sterilized, the seeds must have any bacteria or fungi riding on them destroyed, but without injuring the seed. This is done using certain chemical techniques. Once the seeds
have been disinfected, they are sown on the media; this mmust be done in a sterile environment, usually provided in a glove box or in specially filtered air, produced by a high efficiency particle air (HEPA) filter.
If the seeds are viable and the conditions are correct, they will germinate in several days or weeks (sometimes months). After several weeks or months on the germination medium, they must be transferred to a new
medium in a process called replate. Once they are on replate medium, they may continue to grow, or be transferred to another replate flask. After several months or even years, the seedlings have grown large enough
and produced roots to the point where they stand a good chance at surviving out of flask, and are removed.
The entire process can take over three years, but 12-18 months is typical. This is one reason that orchids are expensive relative to other plants- they require specialized conditions for germination, and are very
slow to grow. On the bright side, they’re kept absolutely sterile, and unless the flasks get contaminated, they are free of pests and pathogens.
While this sounds remarkably difficult and technical, it is worth noting that these techniques are used every day to produce orchid seedlings in homes and commercial facilities all around the world. Everything
required for orchid seed germination is available on the web, and many components can be organized in your home with ease. The specialized media are available by mail order, and complete instructions for growing
orchids from seed are available in our book and on the web.
Don’t let any of the above scare you off, but be forewarned that just scattering orchid seeds in dirt isn’t very effective, if at all. If you have any questions, feel free to ask us and we’ll do our
best to help.