Last updated: 20th September 2002

Family: Compositae

Genus: Calendula (Tribe: Calendulae)

Species: officinalis

Source: CSL Files		Source: CSL Files

Contents

General Background
Details of Quality Characteristics
Current Production and Yields
Constraints upon Production
Markets and Market Potential
Other Information
Research
Useful Websites
BioMat Net
Contacts
References

General Background
Pot marigold (or Calendula) is a perennial or annual herb originating from southern Europe and Eastern Mediterranean area (Flora of the British Isles, 1987, New crops for temperate Regions, 1993). Marigolds are a well known garden plant. There are two varieties easily distinguishable by their fruit sizes, C. vulgare with a fruit diameter of 3.5 mm and C. microcarpum with a fruit diameter of 1.5 – 3.0 mm.

The annual form is more widely grown and grows to a height of 50-75cm and is usually multi-stemmed, with a strong taproot. The vegetative parts of the plant are mid-green in colour and the stems are angular and covered in fine hairs. The lower leaves of the plant are paddle-shaped whilst the upper leaves are smaller and more pointed. The composite flowers are yellow to orange and are born on multi-branched stalks. The flower heads are heterogamous. i.e. the outer flowers are female whilst the inner flowers are disk flowers which are pseudo-hermaphroditic and sterile female. The fruit is an achene made up of winged and unwinged types. The seeds are grey or light brown in colour and vary in shape, decreasing in size towards the center of the head. The thousand grain weight for Calendula is 9.6g.

The plant has many traditional culinary and herbal uses. The dye obtained from the flowers is used to colour and flavour foods like rice, soups, cheeses and butter. An infusion made from the crushed foliage has cleansing and antiseptic properties and is used for soothing and healing skin wounds, also as a remedy for certain digestive disorders.


Details of Quality Characteristics
Recent interest has centred on Calendula as an oilseed crop for industrial use. The seed contains 40-46% oil of which 50-55% is highly conjugated calendic acid and 28-30% is the non-conjugated linoenic acid (both C 18:3). The oil could have applications in the manufacture of paints and coatings, cosmetics and some industrial nylon products. There is a large range of genetic material available (which should be possible to increase oil content by cross-breeding).


Current Production and Yields

Van Soest (1993) has postulated that oil production in Calendula should be able to be increased by 50 - 100%. The average yield for calendula in the UK has been determined as 0.38t/ha. (this figure has been based on several years data - taken from the gross margin information in Nix (28). The CARMINA (Calendula as agronomic raw material for industrial applications) project aims to increase this figure to 0.5-0.6t/ha in the near future.


Constraints upon Production
Although a native of the Mediterranean region the plant appears hardy and well adapted to normal climatic conditions of northern and western Europe. Observations in the UK suggest that the plant would be winter hardy in many parts of southern Britain and therefore could be grown as a biennial.

Harvesting is a major constraint on maximising the production potential of Calendula officinalis due to the vast amount of seed which is shed due to variations in maturity throughout the crop. Some of the crop will be mature and ready for harvest while the remainder will still be too moist. If harvest is delayed until the later areas are dry the early maturing plants will shed their seed and yield will be reduced significantly.


Markets and Market Potential
Considerable scientific activity has taken place in many European countries, funded by National Governments and EU, to support and develop new oil crop species. The species identified offer a considerable diversity and oil characteristics but significant further investigation will be necessary to refine and quantify specific commercial opportunities and develop field productive types. Pilot production studies will be an essential pre-requisite to achieve full commercialisation. Currently only Pot Marigold appears to be moving towards commercialisation.

Calendula is being introduced as a specialist oil crop, the lead being taken by the Netherlands.

The main non food applications for Calendula are:
1. Paints and coatings
2. Cosmetics
3. Some industrial nylon products

Paints and coatings
Calendula accumulates a fatty acid in its seed oil which is known as calendic acid. This fatty acid is the most rapidly oxidised fatty acid known in nature and as such has an extensive number of applications in the plastics, paints and coatings industries.

Cosmetics
Historically, Calendula flowers were considered beneficial for reducing inflammation, wound healing and as an antiseptic. Calendula was used to treat various skin diseases, ranging from skin ulcerations to eczema. Internally, the soothing effects of calendula have been used for stomach ulcers and inflammation. Currently there are a wide range of calendula based cosmetics on the market. Calendula products include:
Toothpaste
Shampoo
Cleansing/baby wipes
Skincare products (moisturisers, creams, cleansers, toners)

Calendula oil as a replacement for Tung oil.
Developments with Calendula oil offer a European replacement for tung oil. Tung oil is most commonly used in paints and inks as it contains high levels of polyunsaturated fatty acids. i.e. tung oil is the reactive component in fast drying paints such as yacht varnishes. Calendula has the potential to replace the 5,000t of tung oil imported annually into the UK from China and South America at prices between $1,200 and $2,300. Results from trials carried out in the UK in 1997 indicated a yield potential of at least 2 t/ha at an average 20% oil content. This straight substitution for the somewhat erratic supply of tung oil would represent about 10,000 ha of production in the UK alone.

Calendula oil based paints
Calendula oil is being targeted at the paints and coatings industry, as a diluent of white spirit, the volatile drying component that may soon be limited by legislation as it releases volatile organic compounds into the atmosphere, contributing to high ground-level ozone levels and smog. In October 1999 it was reported in the ACTIN Newsletter that industrial end-users were reported to be processing calendula oil at pilot scale, and the calendula oil-based paints likely to be test marketed within 18 months of the report (ACTIN, 1999).

Calendula cosmetics
Currently there is a wide range of calendula cosmetics on the market. With the current trend in aromatherapy and natural products, this range is likely to increase and become more diversified. Further research and development work is ongoing in the UK, Netherlands, Germany and Spain in agronomy of the crop and technical handling of the oil. Breeding work is aimed at improving the seed yield and uniformity of maturity.


Other Information
Marigolds thrive best in open, sunny situations on light, easily warmed soils. The crop is spring sown and an optimal plant spacing of 60 plants/m 2 is suggested for oilseed production. The emergence time depends on temperature , but there is an almost fixed number of days from emergence to flower initiation. Weed control is very important for vigorous establishment and to reduce difficulties at harvest. A maximum of 50kg/ha of nitrogen fertiliser is necessary with maintenance dressings of potash and phosphate. The flowering period can be extended and is greatest under moist conditions and can last into the period when the crop must be harvested. After desiccation with Diquat the crop is combined.

Powdery mildew (Sphaerotheca fuliginea) presents a problem to calendula, as does aster yellows, a phytoplasma disease transmitted by leafhoppers. The disease causes stunting and malformation, particularly of the flowers and renders the plant economically worthless (N.Callan. 2001. see http://ag.montana.edu/warc/calendula.htm ).

It has also been reported that Heliothis peltigra can infest calendula and this may affect yields (NF-2000 database).

Field trials carried out in the UK in 1995 by Cromack and Smith suggested that the best of the current cultivars should produce field yields in the range of 2.0 – 2.5 t/ha although this had not been successfully achieved on a field scale until recently. Early maturing genotypes appear to be most suitable for climatic conditions of north-west Europe, allowing a more concentrated flowering period and easier harvesting.

Crossings between ornamental marigolds and the less common varieties are being used in Holland and Germany to develop an oil producing crop.


Research

VOSFA
Results from an EU-funded project report entitled ‘VOSFA – vegetable oils with specific fatty acids’ completed in 1998 showed that in the UK Calendula produced an average yield of 1.4 t/ha and a maximum yield of 2.8t/ha (dependent on genotype see table 2). Seed oil content averaged 16.6% with calendic acid content of 45.4%. There was significant variability between accessions in maturity, yield and seed oil content. A plant density of 40 – 60 plants/m2 was found to be optimum. Desiccating the crop with Diquat at around the 70% brown seed stage and direct combining was an effective harvesting technique, but seed losses could be high. Wind volume and straw bed sieve size were important combine settings to minimise seed losses.

Days to first flower, plant height, seed yield, oil and calendic acid content of nine accessions of Calendula officinalis – mean 1994 and 1995. VOSFA Project report (1998).

Following the success of VOSFA a further bid was submitted to the EC in 1997 which focused on the development of Calendula. The CARMINA project was approved in 1998.

CARMINA
Calendula as agronomic raw material for industrial applications. (see NF-2001online database http://www.nf-2001.org ).
The objectives for CARMINA are as follows:

• Develop new and extended known industrial application possibilities of Calendula oil and its derivatives.
• Optimise and develop oil recovery techniques in order to meet the specific requirements imposed by the different end users.
• Identify uses for the seed by-product in animal feeds.
• Develop Calendula officinalis towards economical feasible crop management systems for the main production areas of Europe and develop cost-effective management systems for these areas.
• Improve genetic stocks for desirable agronomic characteristics.

This study is currently ongoing and no commercial results are available as yet. Some more recent objectives set out by the project are as follows:

• Develop paint formulation having high concentrations of Calendula oil in resins of high solid paints and to replace petrochemical solvent in paint by methylcalendulate.
• Improve modest oil production per hectare from 250kg/ha to 500-600kg/ha.

Useful Websites

http://www.hort.purdue.edu/newcrop/proceedings1993/V2-030.html - New crop developments in Europe

http://sg.montana.edu/warc/calendula.htm - Western Agricultural Research Centre


BioMat Net

Pot marigold (Calendula officinalis)

AIR2-CT93-1817 Vegetable oils with specific fatty acids (VOSFA) Agricultural and Industrial development of novel oilseed crops

AIR3-CT94-2199 The use of enzymes in the processing of new oilseeds (UEPNO) to industrial raw material

FAIR5-CT97-3713 Calendula as agronomic raw material for industrial applications (CARMINA)

FAIR5-CT97-3884I CTVO-NET Chemical-technical utilisation of vegetable oils – 1998 workshops

AGRE-0039 Seed oils for new technical applications – SONCA

AGRE-0046 Vegetable oil for innovation in chemical industries (VOICI)


Contacts


References

• Flora of the British Isles; Clapham, A.R., Tutin, T.G. and Moore, D.M. 1987. 3rd edition. Published for Cambridge University Press

• New Crops For Temperate Regions. Edited by Anthony K.R.M. ; Meadley, J. and Röbbelen, G. 1993. Pub Chapman and Hall.

• Toward a UK Research Strategy for alternative crops. Published by Silsoe Research Institute. July 1994.

• Calendula officinalis – production potential and crop agronomy in southern England; H.T.H. Cromack and J.M. Smith. 1998. Industrial Crops and Products. 7. pp 223-229.

• IENICA Summery Report for the European Union. 2000.