Production of Medicinal Herbs
2/1/2001 – Many growers across the nation are interested in producing medicinal herbs which have become mainstream, everyday products. Every month at least one major popular magazine has an article on medicinal herbs. Herb pills, liquid extracts, and capsules are available everywhere including at supermarkets, discount stores, and convenience stores. It only seems logical that with so many products on the market, companies must need growers to produce the plants from which these products are obtained. Right?
Actually, most herb product manufacturers already have their sources, domestic and foreign. There is not a shortage of growers for most herb crops. The medicinal herb industry has been in a growth phase for many years and it has matured. Long gone are the days when growers could produce a field of herbs and expect to find a buyer when the crop matured. That doesn’t mean there aren’t opportunities to grow and sell medicinal herbs. But as you have been told many times before about every other crop you wanted to grow, you need to have your markets established before you grow the crop. The same is true for medicinal herbs. It will be more difficult to find markets for herbs primarily because it is an industry you are probably unfamiliar with. You don’t know who the buyers are or how the industry is structured. So, first you need to educate yourself on the industry by reading trade magazines, searching the Internet, visiting other growers, and attending natural products conventions and conferences. Most growers envision selling their herbs to a raw botanicals materials buyer who then sells it to a large manufacturer of food supplements. I recommend that growers also search out small manufacturers of herb extracts, herb soaps, and aromatherapy products and try to sell direct to them. Production of value-added products is also an opportunity for some growers.
Once you have explored the market, you will probably have some idea of what kind of herbs you want to grow. For the purposes of talking about cultivation, there are two major groups of herbs. The open field grown herbs are produced on a large-scale, in full sun, and should be looked at more as an agronomic crop than a horticultural crop. The second group is the woodland botanicals which are grown in the forest or under artificial shade and are more intensively managed than the first group. Some of the most common open field herbs are dandelion, feverfew, stinging nettle, milk thistle, Echinacea, burdock, valerian, and St. John’s wort. The woodland botanicals currently in highest demand are goldenseal, ginseng, black cohosh, bloodroot, false indigo, and fairy wand.
There are many similarities between growing medicinal herbs and growing fruits and vegetables. The same basic horticultural principles apply, many pest problems are the same, and most of the equipment you own now will be useful. So, to start, site selection is critical. Whether growing in an open field or in the woods choose a well drained site with good soil, access to water, and few hard to control weeds. Weed control can be a big problem when growing herbs, so pick a site with few weeds to begin with or get weeds under control before sowing a crop. Have the soil tested and amend to suit general vegetable production in an open field and for native ornamentals in the woods. If the soil is low in organic matter, now is the time to start building that up through cover crops or addition of composted material. In most parts of the country, it pays to build raised beds for the improved drainage and soil warming benefits.
Obtaining high-quality seeds or planting stock can be difficult. Find a reputable company that specializes in medicinal herbs and has been around for awhile. Ask other growers about their experiences with various companies.. If purchasing root material for planting stock, ask if it is cultivated or wildcrafted and inspect carefully upon delivery.
For many of the field grown herbs, production of transplants is recommended. These can be grown just like vegetable transplants in the greenhouse. Check the germination rates on the seed packages. Keep in mind that most of these herbs have not been bred or developed in any way. The seed you buy may, in fact, have been collected from wild populations. So, germination percentages can be very low or erratic. Many of the open field herbs are planted in the spring whereas most of the woodland herbs are fall planted. Whether direct seeded or transplanted, use mechanical planters if possible to speed the task and save the back.
All of the woodland herbs should be mulched with an organic mulch. In many northern states, wheat or oat straw is commonly used. In the southern states we have had much better success with hardwood bark, bark/sawdust mixes, or leaf litter. If slugs are a problem on your farm, do not use straw. In the open field, some growers have used black plastic mulch with drip- irrigation. This has been quite effective for weed control but in many cases is not cost effective. We have had some success with a strip-till system for many of the herbs listed above.
Many growers are under the impression that herbs don’t have disease or insect problems. Nothing could be further from the truth. It is not uncommon for there to be few if any problems the first year or two that you try to grow the crop. And when we grow a wide variety of herbs together in an herb garden, we don’t usually have any major problems. But if you try to grow medicinal herbs in a commercial, monoculture system, sooner or later you are going to have some insect and disease problems. Keep in mind that there are few, if any, agricultural chemicals cleared for use on medicinal herbs. In addition, many buyers want certified organic herbs. So, controlling pests on herbs can be very difficult. Prevention is definitely easier than control. Good water and air drainage will go a long way towards preventing many problems. Maintaining a healthy soil, not overwatering or overfertilizing, and scouting frequently are necessary to keep pest problems low. Diseases we encounter include most of those you are already familiar with, such as rhizoctonia, pythium, alternaria, phytophthora, and fusarium. Insects commonly found include aphids, mites, whiteflies, cutworms, earworms, flea beetles, and Japanese beetles.
Most of the open field grown herbs are harvested the same season they are sown. Examples of these include burdock, dandelion, and milk thistle. Some are perennials which can be cut and regrown several times, e.g., Echinacea, St. John’s wort, and stinging nettle. For dandelion and Echinacea, several cuttings of the plant tops can be made before harvesting the roots. The woodland botanicals must be grown for three years or more before harvesting the roots. In the meantime, seeds can be harvested and sold.
It is very important to plan for harvest long before the harvest is to take place. Available equipment can often be modified for herb harvest, but this takes time to prepare for. Considerations for harvest are that plants harvested for the herb (leaves and stems) must be kept clean, flowers must be handled gently, and root crops are often fibrous and matted together. We have successfully harvested Echinacea tops and stinging nettle tops with a stickle bar on a BCS two-wheel tractor and simply undercut goldenseal with the same blade we use for strawberry plants.
Once harvested, the herb must be handled according to buyer specifications. Fresh herb must be cooled and transported quickly to the processor. Herb to be dried must put into the driers shortly after harvest to maintain color and quality. Roots must be carefully washed before drying. Roots washers are often constructed of a metal drum, mounted on an incline, that turns slowly while clean water runs over the roots. Root and herb must be very clean. Buyers will ash the product to determine the amount of dirt present. Too much dirt will cause the product to be rejected or bought at a reduced price. Buyers will also test the product for chemical constituency and bacterial contamination.
Drying of both roots and herb should be done very carefully to maintain quality. The key is to keep temperatures low (95-100 degrees F) and air flow high. Modified tobacco barns have worked well and many simple driers have been constructed.
Package the dried herb or root according to buyer specifications. This often means cardboard barrels or boxes (like watermelon boxes) or supersacks. Keep the product dry and cool.
This is just a brief introduction to what is involved in growing medicinal herbs for the market. For more information, I suggest that you consult the following references. There are two excellent books on the topic. The one I currently consider the bible is “Medicinal Herbs in the Garden, Field, and Marketplace” by Lee Sturdivant and Tim Blakley, published in 1999 by San Juan Naturals. The other book, containing excellent color drawings and important chemical and toxicity information is “Canadian Medicinal Crops” by Ernest Small and Paul M. Catling, published in 1999 by the National Research Council of Canada press. I invite you to visit my website which contains articles, photos, and research results on many of the herbs mentioned here and a number of links to herb and natural products websites. I also suggest that you subscribe to some natural products publications such as Natural Foods Merchandizer, Nutrition Business Journal, and HerbalGram. Probably the best investment you can make, however, is to attend several professional, commercial herb conferences and a natural products show. Consider the International Herb Association conference and the Natural Products Expo East.
Jeanine Davis is an Associate Professor and Extension Specialist in the Department of Horticultural Science at North Carolina State University. She is also the Coordinator of the N.C. Specialty Crops Program which is a multi-agency program in eastern North Carolina. She is located off-campus in the western part of the state at the Mountain Horticultural Crops Research and Extension Center in Fletcher. The primary objective of her program is to increase diversity, sustainability, and profitability of agriculture through development of high-value crops such as herbs, native botanicals, specialty vegetables, industrial crops, and organics. A native of Illinois, she spent twelve years of her youth living in eastern Pennsylvania. There she earned a B.S. degree in Horticulture from Delaware Valley College of Science and Agriculture in Doylestown. She then moved to Washington state where she earned both her M.S. and Ph.D. degrees in Horticulture from Washington State University.
This article was first published in the Proceedings for the Vegetable, Potato, flower, Small Fruit and General Sessions volume of the 2001 Mid-Atlantic Fruit and Vegetable Convention held January 30 – February 1, 2001 at the Hershey Lodge and Convention Center in Hershey, PA.