By Matt Gibson
Cardamom is one of the most ancient spices in the world. A perennial bush from the ginger family, cardamom is native to southern India where it grows naturally in the wild. Cardamom is grown in tropical and subtropical regions around the world today.
Cardamom is the third most expensive spice in the world, behind saffron and vanilla, and is used as a culinary spice in many different regions, but most heavily in Middle Eastern, Indian, Nepalese, and Swedish cuisines. Hardy only to USDA zones 10-13, cardamom requires very specific environmental conditions in order to grow successfully, including a high-humidity environment, steadily warm temperatures, consistently moist soil, and no environmental fluctuations.
For those living outside of the climates suitable to growing cardamom outdoors, the aromatic spice can also be carefully grown in containers which can be brought indoors to overwinter or anytime cold weather is imminent. For those growing cardamom in containers, however, note that mature plants can grow up to 10 feet tall, so be sure you have adequate indoor space for the cardamom plants you need to bring indoors during the winter.
The spice, for which the plant is cultivated, is made from the seeds of the plant, which are taken from tiny, paper-thin pods. Ancient Egyptians chewed on the seeds of the cardamom plant as a tooth cleaner, while the ancient Greeks and Romans used cardamom to make perfume.
The spice was brought to Scandinavia by vikings who discovered it while most likely mercilessly pillaging their way through Constantinople. Cardamom has been a staple spice in Scandinavian culinary traditions ever since, where it has found its way into mulled wine, pastry, and bread recipes, many of which are still popular in countries like Sweden and Norway today.
Varieties of Cardamom
True, or green cardamom, is taken from the species Elettaria cardamomum, and is the most popular form of cardamom cultivated around the world for culinary and medicinal uses. Black cardamom is from the species Amomum subulatum, and is somewhat popular in Nepal. Black cardamom is also used culinarily, but only in savory recipes, unlike green cardamom, which is used in savory and sweet dishes.
White cardamom is usually just bleached green cardamom, but it is sometimes a product of the species Amomum krervanh, commonly called Siam cardamom. Siam cardamom, along with black cardamom (also called Nepal cardamom), winged java cardamom, and bastard cardamom, are examples of cardamom substitutes that are made from the seeds of relatives of the traditional cardamom plant, and are widely considered to be inferior to the flavor of true, or green cardamom. These substitutes can be acquired cheaply, and can be used in place of true cardamom due to how expensive real cardamom can be compared to other spices. However, true chefs and refined palates can usually recognize rather easily, when an imitation is being used in a recipe.
There are three main varieties of true, or green cardamom, which are Malabar, Mysore, and Vazhukka. The latter of the three is a hybrid cross between Malabar and Mysore varieties. The mysore variety of cardamom is the most widely cultivated and used variety. It contains higher levels of the compounds cineol and limonene, which gives it a more robust fragrance and flavor.
Growing Conditions for Cardamom
Growing cardamom is quite challenging. The plant has very specific growing conditions, and it will not grow well if each of those conditions are not met. Cardamom needs tropical, very warm to hot temperatures, and high-humidity conditions. Cardamom grows naturally in very humid areas, such as subtropical forests, where temperatures stay between 65 and 95 degrees Fahrenheit and humidity levels stay as high as 75% humidity.
Providing a suitable environment in a non-tropical climate can prove difficult, but it’s not impossible. The best method for growing cardamom outside of the appropriate zones, is to plant it in a container that can be taken inside during drastic temperature changes, or cold weather. Providing high-humidity conditions can be achieved by occasionally misting the plant, or by storing the container in a saucer filled with pebbles and water, just be sure to keep the base of the container out of the water, as you don’t want your cardamom plant sitting in soggy soil.
Plant cardamom (or position cardamom container) in a spot that gets filtered sun or partial shade. Cardamom should never be exposed to direct sun, and should be allowed to bask in the shade of tall trees, as it is accustomed to in its native jungle habitat. Cardamom prefers a sandy, loamy soil type that has been amended with lots of organic matter and well-rotted manure. It prefers a slightly acidic to neutral pH in the range between 6.1 and 6.8, but will tolerate slightly more acidic soils from 5.5 to 6.0 pH.
One of the most important factors in growing cardamom is selecting the right soil medium to plant it in. Cardamom needs a well-draining soil that will stay relatively moist after draining. So the soil mixture that is used for growing cardamom needs to have good water-retention capabilities, so that it remains just slightly moist, like a wrung-out sponge, but is never soggy or waterlogged. Soils with clay-like textures are not suitable for cardamom plants, and will likely kill the plant if they are not amended with better draining mediums.
How to Germinate Cardamom Seeds
If you are growing cardamom from seed, it is important to purchase seeds that are specifically designed for planting. Cardamom seeds purchased for culinary use are usually treated and probably not as fresh as what you would prefer to plant ideally. Once you have the right seeds on hand, it’s time to get them ready for planting.
First, wash the seeds under room temperature water to remove mucilage and any debris that may have accumulated. Dry your seeds by laying them out in the shade. Once the seeds have dried, put them into a glass jar and set the jar in a tray full of cold water. The water should rise up about halfway up the length of the jar. Keep the jar in the cold water until the glass is cool to the touch.
Next, slowly pour a 2.5 percent solution of nitric acid directly over the cardamom seeds in the jar, being sure to coat all seed surfaces. Stir the seeds and solution up with a spoon so that all sides of every seed is covered in solution. After mixing with the spoon for two straight minutes, use a colander or strainer to wash the nitric acid solution off the seeds and rinse the jar. Using a clean colander or strainer, place it in the kitchen sink and fill it with the freshly rinsed seeds. Rinse the cardamom seeds again under running room temperature water.
Then, move the seeds to a bowl filled with room temperature water and let them soak overnight. This will help break down the hard outer coats of the cardamom seeds. Then, select a container or a spot in the garden to plant the seeds in. Provide consistently moist soil and filtered shade.
How to Plant Cardamom Seeds in the Garden
After the threat of frost has passed, plant your seeds directly into the garden or into the container of your choice. Plant seeds about a half an inch to an inch apart right on the top of the soil. Space rows four to six feet apart. With a thin layer of soil, just barely cover the cardamom seeds. Then arrange a thin layer of twigs over the bed where you planted your seeds and cover them with grass or straw. This will help to cover the seeds without submerging them too deeply under the soil, which should speed up the germination process. Water the site deeply until the soil is moist.
Keep an eye on the bed for signs of germination, which usually takes anywhere between 20 and 25 days, but can occasionally take as long as 40 days. If your seeds don’t emerge in the first three weeks, be patient. As long as you followed the steps to properly germinate your cardamom seeds, you should see seedlings before too long.
Once seedlings start to sprout, remove the majority of the mulch, leaving just a thin surface layer around the new seedlings. Once your seedlings have emerged, it is essential to provide them with a good source of overhead shade to protect them from direct sun. Seedlings will quickly wither and die in direct sunlight.
How to Plant Cardamom in Containers
Pick out a container that is at least 10 inches deep and has several drainage holes. Fill the 10-inch (or deeper) container with an all-purpose potting soil [https://www.gardeningchannel.com/container-gardening-soil/]. Fill a saucer with pebbles and place the container on top of the pebble filled saucer. Spray the pebbles in the saucer with water to create a humid environment. Do not allow the water level in the saucer to cover the pebbles, or touch the base of the planter, as you do not want your pot sitting in water.
Next, use your finger to swirl the center of the potting soil in the planter and gently place the small plant into the hole. Shovel the dirt up from around the base of the plant with your hands. Using distilled water, water the plant until the soil is moist just after planting to help ease the transition into its new home. After planting, continue to provide water once per day, keeping the soil slightly moist at all times, but never soaked, or soggy. Spray the cardamom plant occasionally with a mister to improve humidity. Increase watering when the plant blooms in the summer and cut back on watering to every other day during the winter.
Keep the cardamom container in a warm location that is out of direct sunlight exposure, as cardamom plants need shade to survive. Select a temperature-controlled room and a location that is away from windows and doors, where temperatures might fluctuate. Keep the temperature as close to 80 degrees F as possible, but in the range of 72 to 80 degrees. Feed the plant two times per month with a high-nitrogen and low-potassium fertilizer designed for houseplants.
Care for Cardamom
Cardamom needs consistent watering and occasional misting throughout the year. Cardamom is native to rainforests that receive rainfall around 200 days per year, so the plant is made to grow in soil that is consistently moist. It is important that the soil is never allowed to dry out completely, so during the summer, and when the plant is setting fruits, increase watering to twice per day. Reduce watering to once every two days during the winter.
Feed your cardamom plants with a high-phosphorus organic fertilizer twice per month throughout the growing season. Top dress five kilograms of aged manure or well-rotted compost [https://www.gardeningchannel.com/a-guide-to-composting-in-an-apartment/] per clump to the soil each year. Additionally, feeding the soil around your cardamom plants with neem cake will help them thrive.
How to Propagate Cardamom
Cardamom can be propagated by rhizome division and from seed. The easiest method is by division, however, as untreated cardamom seeds can be expensive, and hard to acquire. Cardamom seeds are also quite hard to germinate, while division of the rhizome is a very quick and easy process with a very high success rate.
For directions on how to propagate from seed, refer to the sections above called, “How to Germinate Cardamom Seeds,” and, “How to Plant Cardamom Seeds in the Garden.”
To propagate cardamom by division, use cardamom rhizomes that are at least one year old and with two growing stems. Cut the rhizome with a sharp knife or a pair of garden shears and gently separate it from the plant. Replant the rhizome in cardamom’s specific growing conditions. Keep in mind, if the plant you are dividing is suffering from cardamom mosaic virus, dividing the rhizome will likely transmit the disease to the new plant as well.
Garden Pests and Diseases of Cardamom
Cardamom is resistant to pest attacks, but it is not immune to pests. Aphids can sometimes be found on cardamom plants, and they can transmit cardamom’s most serious viral disease, cardamom mosaic virus. To keep your plants from becoming infected with the virus, keep an eye out for aphids, and quickly treat any aphid presence that you notice. Small aphid infestations can be treated by hitting the leaves of the plant with a burst of water from the garden hose, knocking off the pests with the force of the water. Check back after a few hours have passed to see if the water blast treatment wiped out the aphids, or if the treatment should be repeated. If you are dealing with a large aphid infestation, applying insecticides, spraying with a horticultural soap spray, or releasing ladybugs in the garden, can all help to reduce aphid populations.
Other pests that might attack cardamom are cardamom thrips and nematodes. Thrips can be treated effectively by installing traps. Nematodes are tougher to treat. Nematode infestations can be identified by noticing poor-growth results and plants that appear damaged. If you think nematodes might be the culprit, dig up a plant and inspect the roots. If you notice significant root damage, which is typically caused by nematodes burrowing into the roots, laying their eggs, and stealing essential nutrients away from the plant, you are likely dealing with nematodes.
Unfortunately, there is no treatment for nematode infestations. Not only should plants be removed and destroyed immediately, but the soil may need to be treated with solarization or with chemical nematicides to get rid of the root-eating pests before planting in it again.
Diseases that affect cardamom plants include rhizomes rot, and capsule rot, both of which are caused by waterlogged soil and poor air circulation. If you notice chlorosis of the leaves, where the lower leaves of the plant begin to turn yellow, or premature fruit dropping, or rhizome decay, Rhizomes rot is the likely diagnosis.
To prevent issues with rot, make sure you are planting your cardamom in a well-draining soil, and providing plenty of space between plants to promote sufficient air circulation. Avoid watering plants from overhead by either using a drip irrigation watering system, or by watering at the base of the plant only. Keeping the above-ground parts of the plant dry at all times will avoid issues with rot.
Aside from pests and diseases, there are a few other problems that may occur when growing cardamom plants, each of which can be corrected when you notice signs of the issue developing. If the tips of your cardamom’s foliage turn brown, it is either due to under watering or low humidity levels. Try spraying the leaves down more often to increase humidity and check the moisture level of the soil more often, keeping it slightly moist at all times.
If brown spots start to appear on the leaves, the plant is getting too much sunlight exposure in its current location and needs to be moved to a spot with filtered sunlight. If the leaves start to turn yellow, it is usually a sign that the plant is not getting enough nutrients and needs to be fertilized more regularly, or a sign that the soil that its being grown in is deficient in iron and needs to be amended to improve its mineral content.
How to Harvest & Store Cardamom
In the third year after planting, cardamom will start to bear fruit. Harvesting cardamom fruit should be done manually, and can begin when fruit starts to turn green, dry out, and begin to crack and break.
After harvesting, allow 6-7 days for the pods to dry out and then store them in an airtight container placed in a cool, dry, dark location. Cardamom stores very well, and will stay fresh for several years when stored correctly.
Considering how expensive cardamom is at the grocery store, it makes a lot of sense to grow it yourself and save yourself some money on the spice isle. But not every gardener is interested in trying to grow plants with very demanding environmental needs. Some gardeners want plants that will grow well even when they are occasionally neglected. However, if you are the type of gardener that is up for a challenge, and you would like to incorporate fresh cardamom into your recipes, growing cardamom can be very rewarding.