Cardamom (or cardamon or cardamum) is the classic spice used in Scandinavian baking despite its origins in India and Sri Lanka. Closer to home, it is used to flavor coffee in the Middle East and tea in India. The plants are grown from rhizomes but it is the seeds that are used as spice.
There are two kinds of cardamom. Black cardamom, Amomum subulatum , is grown in Nepal. It has a smokier flavor than the more commonly used green cardamom. Green (or true) cardamom, Elettaria cardamomum, is grown in India and Malaysia and is related to ginger. It has the characteristic flavor combination of ginger, cloves, vanilla and citron.
Cardamom has been in use since ancient times. The Greeks and Romans used both black and green cardamom in their food and perfumes. It is recorded in Sanskrit texts as a medicinal herb. It still used in Ayurvedic medicine.
Cardamom plants are native to tropical rainforests. They are only hardy in zones 10 through 13. The plants require a lot of moisture and humidity. They do not tolerate any dryness. At maturity, they grow to ten feet in height in rich, well-drained soil. They are an understory plant, growing in partial shade or filtered sunlight. Like their cousin ginger, they have fleshy rhizomes and lance-shaped leaves.
The plants must be three years old before they start to produce the seeds we use as spice. Bloomtime is spring with the white flowers appearing at the base of the leaves. The flowers develop seed pods that are harvested in the fall.
It is possible to grow cardamom from seed. Use the freshest seeds you can find. They are only viable for about two years. Sow them in rich soil and cover them with a scant ⅛-inch of soil. Keep the soil warm, at 75⁰F. Germination should occur within 14 days. Seedlings should be planted at least 7 feet apart.
If you live north of the tropics, you can grow cardamom plants in deep containers. Keep them indoors during cold winter. Because they require high humidity, you should mist your plants regularly while they are indoors. Our houses are very dry. You can move your containers outdoors in the late spring when night time temperatures are consistently above 40⁰F. Move them indoors in the fall when night time temperatures fall below 40⁰F.
Whether planted in the ground or in a container, you can begin harvesting the pods in the fall when the flowers have dried out and the pods turn green. Dry the pods on screens for 6 or 7 days, turning them frequently. Once the pods are dry, the seeds are ready to be harvested. Because the seeds lose their freshness and flavor very quickly, they should be stored in their dried pods until they are used. If you are using them ground, delay grinding the seeds until you are ready to use them.
Store your seeds in their dried pods in tightly sealed containers in a cool, dry, dark place as you would your other herbs.