Herbs have a fascinating economic and social history. Ancient civilizations used herbs for healing and in religious ceremonies. Over time, herbs were woven into myths, lore and legends. Today, many herbs are commercially produced for various reasons, including usage for the food industry, natural health remedies and in perfumes and cosmetics.
In our horticulture industry, home-grown herbs are becoming more and more popular as consumers discover just how easy they are to grow, use and harvest. From a geometric English herb garden to an apartment balcony in Brooklyn, there is room for herbs in every household. Growers looking for something to add can count on herbs to have wide appeal.
The extensive selection can be overwhelming. Starting with a basic variety list is the best advice for a commercial greenhouse grower looking to supplement its offering. Common herbs that consumers routinely ask for include; basil, catmint, chives, cilantro, dill, lavender, mint, oregano, parsley, sage, rosemary and thyme.
Many herbs can also be promoted for landscape use as well as in the kitchen. These are dual-purpose plants that have ornamental value in addition to their culinary appeal.
Cultivars Of Interest For The Landscape
There is no rule against planting herbs directly into the garden border, if it can be managed without the use of chemicals. Herbs are often critter-resistant due to their strong fragrance, which is an added plus for the gardener.
The Lavandula angustifolia Ellagance series is a great example of lavender from seed that does not require vernalization to flower and comes in purple, lavender-blue, white and a new pink-flowering form. Nepeta ‘Junior Walker’ is a compact form of catmint that retains its habit, shape and floriferous vigor, year after year.
Ocimum basilicum ‘Kasar’ not only makes great pesto, it is fabulous as a landscape plant with its deep-green foliage splashed with purple and long-lasting lavender flowers.
Rosmarinus officinalis ‘Barbeque’ is a terrific shrubby rosemary that is very bright green in color. Plant it in the ground next to the patio and use the long, fragrant stems as skewers on the grill.
Salvia elegans ‘Golden Delicious’ is a gorgeous plant that becomes a shrub-sized specimen by late summer. When the bright red flowers appear in fall on the chartreuse foliage, it is a great thrill. The leaves smell just like pineapple, which is an additional draw for customers. There are also many choices of thyme that work well in stepping stone or rock garden plantings.
Crop Production And Timing
Herbs are generally produced in 31/2- to 41/2-inch containers. One liner or seed plug per pot is usually enough. A 128-cell will work nicely for this size. However, pinching is required to help shape the plant in most cases. Some growers prefer a bigger, 72-cell liner that will have already had a pinch or two and will not require additional handling after transplant.
Six-inch or 1-gallon containers can also be used as the finished size, especially for herbs that are more for the landscape. While most herbs are sold green in smaller sizes, the larger pot size for garden borders will sell better when they are in bloom. This is important to remember because many types of lavender require vernalization to flower.
Pinching is a must for most herbs. Liners or seed plugs that have not already been pinched will benefit from a pinch at transplant or about two weeks after transplant. It is best to evaluate on a case-by-case basis.
If growing from unrooted cuttings is an option, it is recommended to start with a small cell size that can be bumped up into the 31/2- to 41/2-inch containers. One cutting per cell is recommended, except for thyme, in which two cuttings per cell are recommended. Most herbs will fill out a 128-cell liner in about 6 weeks. A pinch after propagation is recommended.
Growers generally receive unrooted cuttings in December and January, transplant the liners or plugs in February and March and sell finished pots April through June. Not much is carried through the winter unless plants are in larger containers.
It will take about four to five weeks for basil, catmint, chives, cilantro, dill, mint, oregano, parsley, sage and thyme to finish a 41/2-inch container from a 72-cell liner planted in March. It will take about 6 to 8 weeks for curry, tarragon, lavender and rosemary.
If growing mixed containers of herbs, be aware of the growth rate for different types and adjust plant dates or transplant cell sizes accordingly. For example, plant the slower-to-finish rosemary early or begin with a larger container or cell for a mixed container with parsley, sage and thyme. Herbs that need more time are: curry, lavender, rosemary and tarragon. At retail, displaying a finished, mixed herb container next to the table with the small herb pots can boost sales.
Proper Culture, Not Chemicals, Is Necessary For Disease Control
Few chemicals are registered for herbs so it is essential to practice good culture and growing habits in production in the late winter and early spring months. Read labels carefully, as some chemicals may be labeled for specific herbs, but not all. Use good sanitation methods and discard diseased plant material. Eliminate weeds and scout often to detect problems.
The main disease problem when growing herbs is Botrytis. This gray mold is happy to take hold of tender, young herbs, especially when growing under damp or low-light conditions. Good airflow will aid in the prevention of Botrytis and other diseases. Downy mildew and powdery mildew are other common diseases that can be found on herbs. Common pests include aphids, two-spotted spider mites and whiteflies.
Spacing is generally not required when producing in small pots, since the production time is relatively short. However, there will be better airflow and less chance of Botrytis with good spacing, and this is highly recommended if sales or shipping are delayed.
Herbs require well-drained media or soil and will not thrive in wet conditions. Use the maximum available light intensity for best growth. Supplemental day lighting may benefit growth during darker days in winter. Try to time watering for the mornings on sunny days.
Herbs Need Sunny Days And Minimal Fertilization
Fertilization requirements are relatively low. Apply 100 to 150 ppm nitrogen every third irrigation from a complete NPK fertilizer with micronutrients that contains the majority of nitrogen in the nitrate form. Plant growth regulators are not permitted on herbs, so avoid over-fertilization, which will encourage soft, stretched growth. This type of growth is also more susceptible to disease.
The soil pH should be between 6.0 and 6.5 with the exception of lavender and thyme, which prefer a slightly more alkaline soil.
Most herbs are produced with night temperatures between 55°F and 60°F (13°C and 16°C). Day temperatures are normally about 5° to 10° higher. An exception to this is basil, which requires warmer night temperatures of about 65°F (18°C). Heat or ventilate moist air at the end of the day to reduce relative humidity overnight.
Help your customers add an element of freshness and flavor to family meals along with the added benefit of season-long interest. We know growing edibles as well as other forms of gardening can boost your customers’ well-being. Growing herbs for the first time can hook a young or novice gardener and develop a customer for life. Entice them with these multi-purpose plants that are satisfying and easy to grow for culinary, landscape and even decorative use.