Who can grow Cypripedium seedlings?

Photo of C. guttatum Whether you can grow our seedlings depends greatly on where you live. Cyps are temperate orchids and have adapted to temperate climates by becoming dormant during times of inhospitably cold weather. Most species require several months at near-freezing temperature during dormancy to become "vernalized," i.e., brought to the condition they are normally in at springtime, so that they can produce leaves. If your climate does not offer several months of temperatures near- or below-freezing, your plants probably will not leaf-out normally unless given artificial refrigeration during the winter.

As an example of the problems of growing a species outside its native range, consider C. guttatum, shown at right, which is a native of Alaska. While the plant thrives here in Minnesota, it would not be expected to survive in the southern U.S. Growing the plant is difficult even in northern states such as New York and Washington although this species has been grown successfully as far south as Iowa. The difficulty is that C. guttatum demands a cool root zone, and maintaining low soil temperatures in climates where both days and nights are warm is problematical.

If you plan to grow your plants outdoors, choose only those from areas similar to yours climatically. Growers in northern areas should choose species from northern climates, as plants native to warmer areas may not survive freezing of the ground. People in the south should only attempt southern species as northern species may not vernalize properly. Species from humid climates may die of desiccation in areas with low summertime relative humidity. Species from dry areas may die of too much moisture in rainy climates. If seedlings are selected from climates different from your own, the plantlets will probably require some combination of greenhouse care, artificial refrigeration, and protection from excessive rainfall. Protection from pests is also essential. Even in ideal climates, the protection of a greenhouse allows the horticulturist to keep better watch on specimens and to provide better control over the environment of the plants.

Patience is demanded.

As for most orchids, growth is slow. Although precocious individuals of some species occasionally flower after one or two seasons of growth, normally three, four, or more years are required to reach flowering size. Growers of tropical orchids are used to such delay, but "power gardeners" or others seeking instant gratification are bound to be disappointed with these seedlings. Waiting for your Cypripedium to bloom is like waiting for a small fruit tree to grow up and bear fruit.

Photo of C. parviflorumPhoto of C. arietinum

Two examples of early-blooming specimens. The C. parviflorum var. parviflorum at left bloomed the third season, i.e., two years, after potting. The C. arietinum at right flowered the very next year after potting! Such precocious development should be treated as a pleasant surprise, not an expectation.

How to grow our seedlings

The seedlings, generally with shoots only one or two centimeters long and roots three to five centimeters, arrive sealed in plastic bags.  If the bags of seedlings are received in the spring, the plants have already been vernalized and are ready to be planted out. When weather is not suitable for planting out immediately, the bags may be kept in a refrigerator until conditions improve. If the seedlings are returned to refrigeration upon receipt, they should be checked frequently to make sure the shoots are not elongating in the fridge.

The seedlings may either be planted in an inorganic material such as perlite and fed with very dilute fertilizer solutions during the growing season or planted in a soil mix to which perlite, sand, or other material has been added to lighten the medium and promote drainage. The details of the mix, the amount of water, the intensity of lighting, and the temperature requirements vary considerably from one species to another. We supply detailed growing instructions with all our seedlings. The following photo sequence shows C. reginae seedlings planted in a square pot and their subsequent development:

Photo of pot The photo at left shows five C. reginae seedlings planted at the proper depth with the tips of the shoot buds barely protruding above the soil. The pot is approximately 16 cm (6.3 in) on an edge.

Photo of pot One month later, the same five seedlings have produced leaves. The plastic scale is 15 cm (6.0 in) long.

Photo of pot Two months after the first photo was taken, these five seedlings have the maximum leaf development for the season. All additional growth this season will occur in the roots.

Because our seedlings are small, they require great vigilance by the grower. Our young plantlets are barely a meal for many an invertebrate pest! Some growers have built small hardware cloth cages around their plants or put plastic berry boxes over the seedlings for protection from predators. The moisture content of the soil is critical. If the soil is too wet, the plants die from lack of oxygen or from disease, but because the roots are so short, the seedlings may die quickly if the upper few centimeters of the soil become dry. The grower must check plants daily or even more often during periods of unusually hot, dry, or wet weather.

Photo of potPhoto of plant

Left: A community pot of C. reginae seedlings one year after potting.
Right: A seed-grown C. reginae plant three years, i.e., the fourth season, after planting out. This specimen had also flowered the previous season.


Cypripedium seedlings can be grown indoors under artificial lights. The photo below shows a flat of C. reginae seedlings under a six-inch high plastic dome being illuminated by two wide spectrum 40-watt fluorescent grow light tubes. Such lights are barely bright enough, and much better results can be obtained using metal halide lights. LED grow lights show much promise.

Photo of seedlings under fluorescent lights