From Sean Westerveld, Ginseng and Medicinal Herb Specialist, OMAFRA:

There are over 4,000 medicinal herbs that can be cultivated or grow naturally in
Canada and many more that could be grown in a greenhouse. The cultural requirements
of medicinal herbs are often very unique and specialized. Many of the herbs have had
minimal breeding over the years to overcome problems such as seed germination,
consistency from plant to plant, and adaptation to field or greenhouse conditions. Many
are adapted to a forest environment and require culture directly in the forest or under
artificial shade. In addition, some have developed close associations with organisms in a
natural environment and may be very difficult to cultivate elsewhere.

While there are many medicinal herbs that can be grown, their markets are often
very limited and specialized. Considerable market research may be required before
growing a medicinal herb. Because of the limited market for some medicinal herbs, the
entry of one new grower into the market could cause a dramatic decrease in price due to
over-supply.

Medicinal herb growers also have to consider the end use of the herb. Trained
natural health practitioners are required to prescribe and properly use medicinal herbs
because many can be dangerous if used improperly or used in conjunction with other
drugs. Proper identification and traceability of medicinal herbs is essential to avoid
unintended negative consequences in the end user. Growers also need to keep in mind
that the sale of natural health products is governed by Health Canada, under the Natural
Health Product Directorate. Medicinal herbs are covered by the regulations if specific
health claims are made at the point of sale.

Medicinal herbs also differ from vegetables and culinary herbs in that quality is
not necessarily related to visual appearance, but rather to the concentration of medicinally
active components in the harvested tissue. These medicinally active compounds are often
affected by the growing environment. As a result, growers will have to grow a consistent
crop under very specific conditions to achieve maximum quality and price. Laboratory
tests may be required to verify product quality.