DEPARTMENT: AGRICULTURE LEMON BALM PRODUCTION

PRODUCTION GUIDELINES FOR LEMON BALM (Melissa officinalis) __________________________________________________________________________ PART I: GENERAL ASPECTS 1. CLASSIFICATION Scientific name: Melissa officinalis Common names: Balm Mint, Sweet Melissa, Lemon Balm, Sweet Mary, Honey Plant, Cure-all, Dropsy Plant. Family: Labiatae __________________________________________________________________________

2. ORIGIN AND DISTRIBUTION Lemon balm is one of the mint family and indigenous to Southern Europe, the Mediterranean region, Western Asia, and North Africa and it is now cultivated worldwide. Melissa refers to honey or the honey-bee because the plant is so attractive to bees; and officinalis means a plant that is officially used in medicine.

The Greeks called it "melisophyllon" meaning "bee" and phyllon, denoting "leaf." The Romans referred to the plant as "apiastrum" from apias, to mean simply "bee." Sixteenth-century gardeners rubbed the leaves on beehives to promote the production of honey from within.

__________________________________________________________________________ 3. PRODUCTION LEVELS AND AREAS 3.1 . SOUTH AFRICA Yield Lemon balm yield 10 to 25metric tons of plant material per ha. It has a low oil recovery rate of approximately 0.03% or 3 to 7.5 kg per ha. The oil content of fresh leaves averages 0.1 percent or less with a large range between 0.01 and 0.13%. Dried Lemon balm yields 5 metric tons per ha. 3.2. INTERNATIONALLY

Hungary, Egypt, Italy, for dried herb production and Ireland for essential oil producton.

__________________________________________________________________________ 4. MAJOR PRODUCTION AREAS IN SOUTH AFRICA Lemon balm is grown on a small scale production in the Lowveld of Mpumalanga province, Kwazulu Natal, Gauteng and the Eastern and Western Cape. __________________________________________________________________________

5. DESCRIPTION OF THE PLANT Lemon balm is a spreading herb with a short root-stock and square branching stems that grows 30 to 60cm high. It has pairs of broadly ovate or heart-shaped crenated or toothed leaves at each node. The leaves are 30 to 50mm long, shiny on top, wrinkled and deeply veined. The plant has a distinct fragrant lemon scent and taste. It has small, white or yellowish to pale blue flowers in loose, small bunches emerging from the axils of the leaves and appears in late spring through midsummer. The top of the plant dies down in winter, but the root is perennial.

• ESSENTIAL PART

The fresh and dried plant is used for essential oil extraction. The dried plant is used for extraction of medicinal compounds as well as for health tea. __________________________________________________________________________ 6. CULTIVARS There are no cultivars registered in South Africa. Plant material and seed should be sourced from reliable suppliers. ____________________________________________________________________________ 7. CLIMATIC REQUIREMENTS 7.1 . TEMPERATURE Lemon balm flourishes in full sun and grow best in moderate temperatures. It should be cultivated in temperate and sub-tropic regions. It can survive moderate frost. 7.2 . RAINFALL ____________________________________________________________________________ 8. SOIL REQUIREMENTS

Lemon balm grows best in fertile, deep, well-drained soils with a pH of 5 to 7.5. The plant can be grown in clay and clay-loam soils. Melissa grows best in alluvial soil, excess water is harmful, while yields diminish in light and dry soils. (Guenther).

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PART II: CULTIVATION PRACTICES 1. PROPAGATION Lemon balm is easy to grow from seed sown in the spring or early autumn. The seed is very small and should be covered with only a fine layer of soil. Direct seeding can be done at 7-9kg/ha. It is a practice only done where weed control is efficient and specialized planters can be used. Lemon balm is usually grown from seeds sown in a greenhouse and then transplanted into the land. Seedlings are very sensitive to damping off and therefore it is better to allow the seeds to germinate uncovered.

Lemon Balm seedlings (Photo:WG Alberts) Stolons are the faster and easier way to establish Lemon balm. Stolons should contain three to four buds each. The stolons should be planted early enough in autumn, for the plants to become established before the first frost. If heavy frost is expected in winter, mulching will help to protect the plants. Whenever there is a possibility of soil borne disease or pests that can contaminate a new land, it is safer to use seedlings grown from seed. ____________________________________________________________________________ 2. SOIL PREPARATION

Soil analysis should be carried out in time to determine fertilizer requirements.

Ultimately, building organic

matter and humus in the soil is a matter of managing the soil's living organisms.

SOIL PREPARATION PRACTICES

Good topsoils have an abundance of good soil life and high humus content, balanced with minerals and sufficient plant nutrients. Producers that treat the soil correctly will have the benefit in producing crops of high value with less input in terms of weed, pest and disease control.

Herbal and essential oil crops grown on natural soils yield products that is of high quality and in demand globally.

Good soil management principles will ensure sustainable crop production with improved soil quality over time.

SOIL MANAGEMENT PRINCIPLES

• Good topsoil is abundant with soil life. • Soil micro organisms cycle nutrients and provide many other benefits such

as disease protection, mineral absorption and plant food. • Organic matter is the food source for the soil organisms. • Humus is only part of organic matter in the soil but has a profound effect

on the structure of many soils. • When humus is lost, soils tend to become hard, compact and cloddy. • Humus affects aeration, water-holding capacity and permeability. • Humus usually increases the ability of the soil to resist erosion. • Humus enables the soil to hold more water and its effect in promoting soil

granulation and thus maintaining large pores through which water can enter and percolate downward.

• An abundant supply of organic matter will favor the growth of beneficial soil organisms which will benefit plants.

Feed the soil, not the plant" is fundamental to

organic soil management

• Excess nitrogen speeds up the decomposition of organic matter.

• Insufficient nitrogen slows down organic matter decomposition and starves plants.

• To build soil organic matter, the production or addition of organic matter must exceed the decomposition of organic matter.

• High rainfall and temperature promote rapid plant growth, but these conditions are also favorable to rapid organic matter decomposition and loss.

• The soil should have plant or mulch cover to protect it from water and wind erosion and extreme temperatures.

• Use soil laboratories that can monitor nutrients as well as soil life and give appropriate advice.

• A soil analysis will guide the producer in the correcting of the nutritional status of the soil in order to provide the crop with optimum growing conditions such as a balanced nutritional status and correct pH.

• Organic matter content, soil texture, structure and type, nutrient and mineral status and the relationship thereof need to be known to ensure that there is no degradation taking place and improvement can be monitored.

• Soil preparation need to be done according to good cultivation practices. • Soil fertility levels need to be within acceptable ranges before a soil-

building program is begun. • Some tillage practices and implements are extremely harmful to soil. • Tillage speeds up the decomposition of soil organic matter and therefore it

needs to be done with caution. • Tine implements are less harmful than mouldboard and disc ploughs. • Mouldboard and disc ploughing unnecessary speeds up the

decomposition of organic matter, destroys earthworm habitat, destroy soil texture and structure and increases erosion and compaction.

• Working the soil when it is too wet or too dry is harmful. • Wind breaks, minimum tilling or no till practices can be employed where

wind can erode soil or damage crops. • Contour sloped areas to ensure that the soil is not eroded by water. • Improvements in the soil’s physical structure facilitate easier tillage,

increased soil water storage capacity, reduced erosion, better formation and harvesting of root crops, and deeper, more prolific plant root systems.

Soil aggregation is the process whereby individual soil particles are joined into clusters or “aggregates.”

Some factors that destroy or degrade soil aggregates are:

• Bare soil surface exposed to the impact of raindrops • Removal of organic matter through crop production and harvest without

return of organic matter to the soil. • Use of chemical fertilizers such as anhydrous ammonia, which speeds up

decomposition of organic matter. • Excess nitrogen fertilization. • Allowing the build-up of excess sodium from irrigation or sodium

containing fertilizers.

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3. PLANTING • PLANTING DENSITY/SPACING

Recommended planting density of 45 000 to 100 000 plants/ha from seed, seedlings, root stolons. Suggested spacing is 20 to 30cm apart in the row and 50 to 75cm between the rows. Closer spacing will allow plants to cover area sooner and will result in the highest yields with less weed problems. The plants have a life of 10 years but are usually replaced every five years with crop rotation with a legume crop to rejuvenate the soil.

Lemon balm spreads rapidly (Photos:WG Alberts)

Lemon balm plants can be planted in high densities, so it may be possible to establish the crop on a broad scale. Alternatively, the crop can be planted in beds approximately 1.2 m wide to allow for tractor and implements. Width of beds should be designed so that vehicles can straddle the crop without damaging it during mechanized weed control and harvesting.

Plants spread quickly, and a complete ground cover should be achieved at the end of the first season. The plants have a life of 10 years but they should be replaced every five years with crop rotation to rejuvenate the soil.

__________________________________________________________________________ 4. FERTILIZATION Although specific recommendations are not available for fertilization of Lemon balm, yield and oil content may be increased with nitrogen application several times during the growing season. Lemon balm responds well to additional applications of nitrogen during the growing season, usually applied after harvest to boost new shoot growth. Potassium applications at this time may also be

beneficial. A basal fertilizer application containing nitrogen, phosphorus, sulphur and potassium should be applied annually. An analysis of organic compost will assist to provide correct application rates. Organically grown Lemon balm is high in demand. __________________________________________________________________________ 5. IRRIGATION

The crop has a high water demand. A regular water supply should be provided by overhead sprinkler irrigation.

__________________________________________________________________________ 6. WEED CONTROL Currently there are no herbicides cleared for use on Lemon balm as the plant is mostly used for medicinal purposes and toxic elements need to be eliminated as far as possible. Weed control programs must be strictly maintained as weeds compete with the crop for available nutrients and thereby reduce yields. This is especially important in the early stages when plants have not yet covered the soil. Some weeds may contain volatile compounds which are extracted along with the mint oil during the distillation process. It can contribute to off-flavors, resulting in lowered oil or extract quality. Certain weed species are more harmful and can reduce the marketability of the crop. Amaranthus spp.(pigweed) and Datura spp. (thorn apple) can contaminate crop quality severely. Hand removal of weeds need to be done. Always remove these weeds in time before they seed. WEED CONTROL PRINCIPLES:

• Do not allow weeds to seed in the land • No till practices result in less weeds • Shade out weeds by plant canopy, high plant density, closer row width, if

moisture content of soil and crop specification allow for it. • Use manual or machinery control • Organic control measures such as flame weeding and UV radiation can be

used where applicable and if the crop can tolerate the method. • Some seeds germinate when exposed to sunlight. Use night ploughing as

option for fewer weeds. • Use herbicides with low toxicity and rapid breakdown in the soil. • Select target-specific herbicides. • Take care to use herbicides according to manufacturer’s specifications. • Be aware of contamination possibilities. • Make sure of correct handling, safety procedures and first aid measures if

accidental poisoning takes place. • Record keeping of herbicides, control measures and results. • Ask for assistance from Agriculture specialists if in doubt.

Use the publication ‘Guide to the use of herbicides’, A – 2004, Compiled by Hermien Grobler, J B Vermeulen and Kathy van Zyl (**see PUBLICATION FROM DEPARTMENT OF AGRICULTURE)

____________________________________________________________________________ 7. PEST CONTROL

Whitefly, spider mite and thrips are pests that occur on Lemon balm.

• Whitefly has piercing-sucking mouthparts which they use to suck sap from the leaves of plants. They also excrete large mounts of honeydew which sooty-mold grows upon.

• Spider mites feed preferentially on the lower stem, and then move on to feed on the upper section of the plant and on leaves. Leaves may later turn yellow and drop. Silk webbing may be present when infestation is heavy.

• Thrips feed on leaves with their piercing and sucking mouthparts and damage the pants causing browning and drop of leaves. They can also be vectors of other diseases.

Extension officers should be contacted for information on the identification of insects and diseases and for recommended controls. PEST CONTROL PRINCIPLES:

• Follow a pest management program. • Regular scouting of the crop is needed. • Early detection and management of pest problems can often prevent

major problems. • Correct identifying of pests and natural beneficial predators. • Natural pest control measures to be used as first choice. • Correct nutrient deficiencies or excesses • Introduce and use biological controls natural predators, parasites,

nematodes, fungi, bacteria, and beneficial viruses. Avoid using chemicals that kill such organisms.

• Other organic methods such as reflective mulches, beneficial insects, insecticidal soaps, plant extracts, traps and handpicking pests

• Use controls that target specific taxonomic groups, eating habits, or life stages: insecticidal soaps, horticultural oils, pheromones, and growth-regulating natural substances such as neem oil.

• Organic insecticides have higher safety standards. • Select target-specific synthetic pesticides, insecticides, these often must

be applied at a specific point in the life cycle of the pest or disease.

• Use only registered pesticides with extreme caution according to manufacturer’s specifications.

• Produce should not be contaminated with pesticides when harvested. • Ensure that live insects and mites do not infest export shipments. • Make sure of correct handling, safety procedures and first aid measures if

accidental poisoning takes place. • Record keeping of pests, control measures and results. • Ask for assistance from Agriculture specialists if in doubt.

Use the publication ‘Guide for the control of plant pests’, A – 2002., Compiled by Annette Nel, Mareli Krause, Neervana Ramautar and Kathy van Zyl (**see PUBLICATION FROM DEPARTMENT OF AGRICULTURE) __________________________________________________________________________ 8. DISEASE CONTROL Lemon balm is susceptible to mildew. DISEASE CONTROL PRINCIPLES:

• Follow a disease management program. • Regular scouting of the crop is needed. • Early detection and management of disease can often prevent major

problems. • Correct identifying of disease is needed. • Natural disease control measures to be used as first choice. • Use clean seed and plant material from a reputable supplier. • Grow the crop in disease-free soil. • Maintain disease free fields. • Rotate diseased crop with non susceptible crops such as oats, rye

buckwheat, and sun hemp or other crops specified. • Remove diseased leaves or plants to reduce field inoculum levels • Control moisture since high humidity on free water plants strongly favours

fungus disease. • Increase spacing between plants to improve air movement and reduce

leaf wetness periods for fungus diseases. • Encourage or introduce natural predators to control vectors that carry

disease. • Increase the organic matter in the soil which will enhance microbial activity

and favour pathogen reduction. • Laboratory analysis is recommended to identify the causal agent when

diseases are first encountered. • Ensure that no diseased material infest export shipments.

• Destroy diseased material properly by burning where serious threat of contamination exists.

• Do not incorporate diseased material into compost. • Use organic disease control as first choice if possible. • Select target-specific synthetic fungicides and bactericides. These often

must be applied at a specific point in the life cycle of the disease. • Use only registered chemicals to combat disease and use with extreme

caution according to manufacturer’s specifications. • Produce should not be contaminated with harmful chemicals when

harvested • Make sure of correct handling, safety procedures and first aid measures if

poisoning takes place. • Record keeping of diseases, control measures and results. • Ask for assistance from Agriculture specialists if in doubt.

Use the publication, ‘Guide for the control of plant diseases’, A– 2003. Compiled by Annette Nel, Mareli Krause, Neervana Ramautar and Kathy van Zyl (**see PUBLICATION FROM DEPARTMENT OF AGRICULTURE)

Powdery mildew appears as a dusty white to gray coating over leaf surfaces or other plant parts. It begins as discrete, usually circular, powdery white spots. As these spots expand they will combine, producing a continuous matt of mildew.

Several practices will reduce or prevent powdery mildews. Do not plant in low, shady locations.

Once the disease becomes a problem:

• Avoid late-summer applications of nitrogen fertilizer to limit the production of succulent tissue, which is more susceptible to infection.

• Avoid overhead watering to help reduce the relative humidity. • Remove and destroy all infected plant parts if area is not to large. Do not

decompose infected plant debris. Temperatures often are not hot enough to kill the fungus.

Chemical

If cultivation controls fail to prevent disease buildup or if the disease pressure is too great, an application of a fungicide may be necessary. These include:

• sulfur, • neem oil • potassium bicarbonate

Apply fungicides at 7 to 14 day intervals to provide continuous protection throughout the growing season. Follow the instructions on the fungicide label for

use on specific plant species, varieties, rates to be used, timing of applications, and waiting periods before harvest.

__________________________________________________________________________ 9. OTHER CULTIVATION PRACTICES

• MULCHING

Use of plastic or organic mulches are recommended to prevent weed growth.

__________________________________________________________________________ 10. HARVESTING

• MATURITY TIME AND METHODS

The aerial parts are harvested from early summer onward, but are best just before the flowers open when the concentration of volatile oil is at its highest.

Harvesting is done by hands on a clear warm day, as quality will be reduced if the leaves turn brown.

Foliage can also be cut with a mechanical cutter.

__________________________________________________________________________ PART III: POST-HARVEST HANDLING

• SORTING AND DISTILLATION Lemon balm is cut and then dried in the shade to preserve the chemical composition of the plant. Too much direct sunlight will cause volatile oils to disappear. The volatile oil is obtained by steam distillation of the dried herb. The chemical properties of the dried plant material are also extracted by different methods. The crop can be steam distilled immediately after harvest.

• GRADING Colour, moisture content and absence of mould are properties that will ensure a god price for the dried herb.

• PACKAGING The dried herb can be put into bags that allow air flow. Plastic bags can result in

fungus growth if too much moisture is present. Essential oils can be packaged in bulk or smaller quantities. Smaller quantities usually have higher prices due to extra handling and packaging materials needed. Ceramic, dark coloured glass, fluorinated plastic and epoxy coated aluminum containers are used. Essential oils are volatile and as such need to be handled with care. STORAGE The oil is subject to oxidation; as a result it should be stored in filled sealed containers, out of light and kept cool. Keep it air tight and do not expose it to heat or heavy metals.

Dried Lemon Balm ready for the herbal tea market (Photo:WG Alberts)

• MARKETING Lemon balm is mostly marketed for medicinal purposes as a dried product. The end producer will market it as medicinal extracts or as health herbal tea bags. Fresh Lemon balm is marketed as culinary herbs on the fresh produce markets or supermarkets. Essential oils are sold in bulk to wholesalers where it is packaged in smaller quantities. Smaller quantities is marketed to the aroma therapy industry. ESSENTIAL OIL MARKET

The market of essential oils in SA is divided into local buyers and international buyers. The local buyers include marketing agents and companies from chemical and pharmaceutical as well as food and flavouring industries. The international buyers are divided into Flavour and Fragrance Houses, Cosmetics and Personal Health Care, Aromatherapy and Food Manufacturers who buy in large quantities. The major market in the world for essential oils is the United States followed by Japan and Europe. Production continues to be concentrated in Europe, with seven of the world's largest essential oil processing firms. In the United States the major users of essential oils are the soft drink companies. Japan accounts for 10% of the world demand. The Canadian market is dominated by the United States perfume and flavouring industry. France dominate the world perfumery market and Switzerland is one of the leaders in the pharmaceutical field. Britain and India are known to feature strongly in the flavoring sector. The essential oil industry is characterized by a number of difficulties including lack of stable quality, inconsistent supplies, and variability of active ingredients due to environmental effects. This has encouraged many of the end users to depend on synthetic oils in an effort to eliminate the above problems. The result is a weaker market for naturally produced essential oils. With the increased interest in "natural" products and new health consciousness of the public, plus the fact that a natural product is perceived to have a superior quality, there is an opportunity, to effectively market natural grown essential oils should the above problems be addressed. Most countries import all its dried thyme mainly from Spain and Morocco, the major world producers. Most bulk dried herbs are produced in countries with low labour costs, so the challenge to producers in South Africa is to produce crops of superior quality at a competitive price. __________________________________________________________________________

PART IV: PRODUCTION SCHEDULES

Production scheduling is part of the overall farm management plan

As farming enterprises are so diverse, a very basic schedule is proposed. Producers need to adapt the schedule to their own needs.

PRODUCTION SCHEDULING BASICS

• Soil preparation (Soil sampling, analysis, rip, plough, disc, harrow, contour, etc.)

• Propagation (Seed, cuttings, other propagation material ) • Planting date. • Growing the crop. • Irrigation. • Fertilizing (each type separate) • Weed control (each separate) • Pest control (each method / pesticide separate) • Disease control (each method / chemical separate) • Harvest. • Post harvest (Distillation, extracts, drying, fresh)

When scheduling production, the important factor to bear in mind is to have sufficient knowledge of the crop that you are farming with.

__________________________________________________________________________ PART V: UTILISATION

The main components of Melissa essential oil are citral, b-caryophyllene; germacrene D, citronellal, eugenol acetate and geraniol.

Lemon Balm, is one of the most expensive of the essential oils but the hydrosol is affordable. The hydrosol has powerful and positive uses for any skin care product. It is antifungal, relieves skin infection and can cure herpes. The hydrosol is considered useful in tonic drinks for 'attention deficit disorder' and dietary uses.

The Essential Oil properties are hypotensive, calming, sedative and anti-inflammatory. Melissa oil is used for insomnia, hysteria and irritability. Will relieve a cold sore if applied externally.

Cosmetic The herb has potent uses in skin and body care. Lemon balm hydrosol is added to clay masks for skin healing. Pharmaceutical and Therapeutically Indicated for headaches, indigestion, nausea, antidepressant, sedative, eczema allergy and insect bites, Infusions of fresh leaves of lemon balm are used medicinally to calm heart spasms, headache, soothe a nervous stomach ,.for depression, nervous exhaustion, indigestion, nausea, eczema and the early stages of colds or flu. Lemon balm has mild sedative properties and has been used to relieve gas, reduce fever, and increase perspiration. Both essential oil and hot water extracts of the leaves have been shown to possess strong antibacterial and antiviral qualities. One of the main uses at present is the ability to prevent the production of a thyroid-stimulating hormone which makes it useful in treating certain hyperthyroid disorders. Culinary Fresh leaves add a delicate flavor to many dishes, oils, vinegars, and liqueurs. Fresh or dried leaves make a refreshing tea, either iced or hot. The fresh leaves and flowers of lemon balm complement all vegetable and fruit salads, stuffings, bean dishes, and marinades for meat and fish. Industrial Used in health tea and other tea blends. Dried leaves are used as an ingredient in pot-pourris. The oil is used in perfume. The leaves and flowers are also used in wine-making and liqueurs. Lemon balm is a traditional ingredient in Chartreause and Benedictine. Other Lemon balm attracts bees, and if it is rubbed on inside of empty beehives it will attract new bee swarms.

It also attracts beneficial insects such as parasitic wasps and tachinid flies that preys on many common garden insect pests.

SAFETY DATA Non toxic. Sensitization and dermal irritation can occur if essential oil is not diluted well. Use in very low dilutions or in hydrolat form.

____________________________________________________________________________ Compiled for the National Dept of Agriculture by members of SAEOPA and KARWIL Consultancy. Contact with growers in South Africa can be obtained from the Southern African Essential Oil Producers Association (SAEOPA). Karen M Swanepoel, by e-mail : kswane@pan.uzulu.ac.zaAdvice and consultation can be organized by: Willie Alberts e-mail: alberts.willem@gmail.com Contact at Department of Agriculture Directorate: Plant Production Systems Private Bag X250, Room 359, Harvest House Building Pretoria, 0001 Tel: +27 12 319 6206 Fax: +27 12 319 6353 To assist the Producer in the use of Agricultural chemicals, the different Guidebooks indicated by ** can be obtained from the National Department of Agriculture, details below.

**Compiled, printed and published by Directorate Agricultural Information Services

Department of Agriculture Obtainable from Resource Centre

Private Bag X144, Pretoria, 0001 South Africa

** For publication information contact: Resource Centre at the Department of Agriculture

Tel (012) 319 7141 or 319 7085 Fax (012) 319 7260