Marigold Cultivation: Varieties, Fertiliser, Care and Pest Control in Bangladesh

Before sunrise, Godkhali in Jhikargachha upazila of Jashore already smells of flowers. The Department of Agricultural Marketing described it in 2020 as the place where the country's biggest flower market comes alive very early in the morning, with traders from Dhaka and elsewhere filling trucks and pickups with flowers for the cities. Among the heaps of roses, tuberoses and gladioli, the bright orange and yellow marigolds are the flowers almost every buyer needs.

Marigold is one of the leading winter flowers of Bangladesh. Weddings, birthdays, anniversaries, home decoration, Victory Day, Independence Day and Martyrs' Day all call for it; BARI notes that marigold is usually used as a loose flower.

This guide explains what marigold is and where it stands in the country's flower trade, which types and varieties are grown, which climate, soil and season suit it, how to raise and plant seedlings, how much manure and fertiliser the Bangladesh Agricultural Research Institute (BARI) recommends, how to pinch and care for the plants, how to deal with the main diseases and pests, and when to harvest. Every rate and dose below is given as the named authority states it.

Marigolds belong to the genus Tagetes in the daisy family, Asteraceae. According to North Carolina State University's Extension Gardener Plant Toolbox, both the African marigold (Tagetes erecta) and the French marigold (Tagetes patula) are native to Mexico and Guatemala, despite their names. Banglapedia, the national encyclopaedia of Bangladesh, lists marigold among the flowers commonly grown in the country, with yellow, red and orange forms of both species.

The African marigold is described by NC State Extension as a tender, flowering annual with fragrant, showy flowers and a long blooming season; its leaves are also fragrant when brushed or crushed. The French marigold is a compact, bushy annual whose flowers come in various combinations of red, orange and yellow, single, semi-double or fully double.

A 2020 article in Krishi Kotha, the monthly of the Agriculture Information Service (AIS), written by officials of the Department of Agricultural Marketing (DAM), noted that flowers had become indispensable at weddings, birthdays and anniversaries, and on occasions such as International Mother Language Day, Valentine's Day, Independence Day and Victory Day.

Commercial flower growing in Bangladesh is young. The DAM officials wrote in Krishi Kotha in February 2020 that it began in 1983 at Panisara village in Jhikargachha upazila of Jashore, when a farmer named Sher Ali started growing flowers on only 0.83 decimal of land. By the time of that article, flowers were grown commercially on about 3,520 hectares in 24 districts. Khulna division had the largest share, 2,600 hectares or 74 percent, followed by Dhaka division with 690 hectares and Chattogram division with 121 hectares.

The same article put the number of flower farmers at about 15,000, with at least 1.5 lakh people directly employed in production and trade and about 7 lakh people earning a living from the sector. In 2014-15, it said, Bangladesh produced 57,000 tonnes of flowers, sold for about 800 crore taka. Marigold accounted for 12,624 tonnes and 8 percent of the market value, behind gladiolus, rose and tuberose.

BARI's Krishi Projukti Hatboi (agricultural technology handbook), ninth edition, published in January 2020, gave a different estimate for the domestic trade, about 500 crore taka a year with demand rising, and put world flower trade at about 60 billion US dollars. The handbook says marigold is popular all over Bangladesh but is grown commercially mainly in Jashore, Kushtia, Jhenaidah, Bogura, Rangpur, Rajshahi and Chattogram.

The DAM article also listed the problems growers face: many farmers lack knowledge of production technology, seed and planting material are scarce in Bangladesh and depend on imports from India, wholesale markets are lacking in big cities, and about 20 percent of flowers are lost between farmer and retailer. It described Godkhali, about 25 kilometres from Jashore town, as the site of the country's biggest flower market.

Growers in Bangladesh know marigolds by several local names, including Chinese, rajgada, African and French types, and by colour: yellow, red, orange, dark brown and mixed red and yellow. The two main botanical types differ clearly in size.

• African marigold (Tagetes erecta): upright and tall. NC State Extension gives a height of 1 to 4 feet, with double flowers 2 to 6 inches across in yellow, orange, mahogany, bronze, creamy white and bicolour. Tall varieties may need staking.
• French marigold (Tagetes patula): short and bushy. NC State Extension gives 6 to 12 inches in height and flower heads 1 to 2 inches wide, borne in large numbers. It suits beds, edges and containers.
• BARI Gada-1: developed in 2009 by the floriculture division of BARI's Horticulture Research Centre, which collected germplasm from nurseries in different regions of the country and selected among it. According to the BARI handbook, it has attractive orange flowers, usually used as loose flowers, plants 60 to 90 cm tall, and a yield of about 7 to 8 tonnes per hectare. BARI says it is suitable for cultivation throughout Bangladesh.

The list of BARI varieties kept by the Department of Horticulture at Bangabandhu Sheikh Mujibur Rahman Agricultural University records it as BARI Marigold-1, released in 2009.

For a grower, the choice is practical. BARI's handbook notes that the French marigold tolerates unfavourable weather better than the African marigold, while the African type gives its best flowers under long days and mild temperatures. Seed of a named variety should be bought from a government Horticulture Centre or a trusted nursery, as the AIS advises for winter flower seed.

Marigold needs a mild climate. BARI's handbook says marigold can be grown all year round in Bangladesh, but yields are lower in the summer and rainy seasons than in winter. The African marigold gives its best flowers under long days and low temperatures of 15 to 21 degrees Celsius; when temperatures rise too high, growth slows, flowers become smaller and production suffers.

Land should be high and well drained, so that water never stands at the base of the plants. Tamil Nadu Agricultural University (TNAU) in India recommends well-drained loamy soil with a pH of 7.0 to 7.5 and says saline and acidic soils are not suitable. NC State Extension adds that marigold does best in full sun, which encourages blooms, and dislikes full shade. The field is ploughed and harrowed four or five times until the soil is loose and friable.

Sources give different calendars, and a grower can choose according to the season they aim for:

• Winter crop: the AIS, in Krishi Kotha of October 2024, wrote that September and October are the right months for winter vegetables and flowers, including marigold, and that seedlings can be raised from seed and planted from the last week of August to December. The original guide's calendar, sowing in a seedbed in November and planting out in December, falls within this window.
• BARI's handbook schedule: sow seed in the seedbed in January and February, and plant 25 to 30 day old seedlings with three or four leaves in the field between February and March.

Marigold is propagated from seed and from stem cuttings. BARI's handbook says plants raised from seed are healthy, tall and more productive, while cuttings are an easy way to multiply a plant and keep the qualities of the variety unchanged.

• Prepare the seedbed or tray. The AIS suggests a potting medium of 50 percent cocopeat mixed with 50 percent other materials such as manure, sand and soil for raising seedlings. Sow thinly and cover lightly.
• Keep the seedbed moist with regular, light watering until the seedlings are established.
• For cuttings, cut healthy branches with one or two nodes and plant them in a moist bed, as the original guide describes.
• Transplant at the right age. BARI recommends seedlings 25 to 30 days old with three or four leaves; TNAU transplants after four weeks.
• Space the plants. TNAU recommends 45 cm by 35 cm, planting on one side of a ridge, with a nursery seed rate of 1.5 kg per hectare.
• Water immediately after planting. TNAU advises irrigating straight after planting and again on the third day.
• Fill gaps: where seedlings die, plant new ones, and thin seedlings where they are too crowded.

For pots, tubs or polybags, a mix of loam or clay loam with well-rotted cow dung is used, and the containers must drain freely. The AIS notes that in rooftop gardens, pots are watered again when the top two inches of soil have dried.

BARI's handbook gives the recommended rates per hectare. When the land is finally prepared, mix 10 tonnes of rotted cow dung, 175 kg of TSP and 150 kg of MOP thoroughly with the soil. Of 200 kg of urea per hectare, apply half as a top dressing 20 to 25 days after planting and the remaining half before flowering begins.

For comparison, TNAU's recommendation for African marigold in Tamil Nadu is 25 tonnes of farmyard manure per hectare, 45:90:75 kg of nitrogen, phosphorus and potash per hectare as a basal dose, and 45 kg of nitrogen per hectare as a top dressing 45 days after planting. Soil differs from place to place, so a grower in Bangladesh should follow BARI's rates or a soil test from the upazila agriculture office.

Water before the soil dries out, and drain any water that collects at the base of the plants. TNAU advises irrigating about once a week or as needed and avoiding stagnant water. In winter, the AIS suggests watering once the fog has cleared and the sun is out, and warns that both too much and too little water harm plants; a wilted plant should be given water a little at a time rather than flooded.

Pinching makes the plant bushy and increases the number of flowers. TNAU advises removing the growing tip about 30 days after planting to encourage branching. The AIS explains pinching as removing the tip of a seedling when it is 6 to 8 inches tall, which brings out two or three side shoots, and notes that cutting flowers before they dry increases flowering.

Tall African marigolds can bend or break. NC State Extension says tall varieties may need staking or a site protected from strong wind and heavy rain, and that spent flowers should be removed promptly because the heavy flower heads can snap stems. Removing crowded buds so that only one or two remain at the top of a branch, as the original guide advises, helps the remaining flowers grow larger.

Weeds should be pulled or hoed out as soon as they appear. The AIS also recommends mulching with organic material such as bark, leaves or wood chips, 1 to 1.5 inches thick, leaving an inch of space around the stem; it keeps moisture in the soil, suppresses weeds and improves the soil as it breaks down.

Marigold is a hardy crop, but BARI's handbook names several problems and gives control measures. The products and doses below are BARI's; before spraying, check with the upazila agriculture officer which products are currently registered, and follow the label and safety instructions.

• Leaf spot: brownish-grey spots appear on the leaves; in severe attacks the leaves dry up and the plant weakens. BARI suggests spraying Trichoderma at 4 grams per litre of water every 10 days, or Autostin or Benlate (0.1%) three times at 15-day intervals as soon as the disease appears.
• Flower rot: grey spots appear on the petals, countless fungal spores form in the folds and the whole flower turns black and rots. Spraying the fungicide Rovral (0.2%) every 10 days controls it.
• Grey mould: brown water-soaked spots on petals, leaves and even stems, followed by a grey to brown powdery layer. Follow proper spacing so the plants get enough light and air, and spray Captan (0.1%) or Thiram 75 (0.3%).
• Red mite: most serious in the dry season from November to April, falling once the rains begin. Leaves lose their colour and the plant can be covered with webbing and die. Spray water on the undersides of the leaves every 3 to 4 days in dry weather; in heavy attacks spray Vertimec 1.8 EC (1 ml per litre of water) or Magister 10 EC (2 ml per litre) every 7 to 15 days.
• Leaf-eating caterpillar: the larvae eat stems and leaves, more so when temperatures are low. Kill the caterpillars by hand and set up perches for birds; in heavy attacks spray Spinosad 45 SC (Tracer) at 1 ml per litre of water.
• Mealybug: sucks sap and weakens the plant, and also harbours fungi. Spray Admire 20 SL (1.2 ml per litre), Rogor 40 EC (1.2 ml per litre), Malataf 57 EC (2 ml per litre) or Fifanon 57 EC (2 ml per litre) every 7 to 15 days.

NC State Extension adds powdery mildew, phytophthora and thrips to the list of possible marigold problems.

BARI advises cutting the flowers with scissors, leaving a short stalk, once they have reached full size; cut this way, they stay fresh longer. The original guide advises picking very early in the morning. BARI's hydroponic trials found that marigold plants generally start flowering 50 to 60 days after planting and each plant gives 15 to 20 flowers. TNAU reports that in Tamil Nadu flowers are picked once every three days from 60 days after planting, that the crop lasts about 130 to 150 days, and that average yield is about 18 tonnes per hectare.

BARI has also tested marigold in hydroponics, growing plants in a nutrient solution instead of soil. Its handbook says seedlings are ready for planting at four to five weeks; the solution's pH should be kept between 5.5 and 6.2 and its EC between 1.0 and 1.5, raised to 1.5 to 2.0 once flowering starts. Older lower leaves are removed from time to time, plants need enough light, and pinching the tips increases branches and flowers.

Handle the plants with some care. NC State Extension lists low-severity poisonous characteristics for both African and French marigold: skin redness, burning pain and blisters can occur when broken skin comes into contact with the sap in sunlight, and the aroma of the flowers can irritate the nose and eyes. Anyone with a skin reaction should see a doctor.

For seed, training and advice, growers can contact the upazila agriculture officer of the Department of Agricultural Extension (DAE), the nearest government Horticulture Centre, or the floriculture division of BARI's Horticulture Research Centre in Joydebpur, Gazipur, which works on flower varieties, propagation by seed and cuttings, keeping flowers fresh and better production methods.

Photo: Muhammad Amdad Hossain / Wikimedia Commons (CC BY-SA 4.0)

Sources: The Agro News (Staff Correspondent), Bangladesh Agricultural Research Institute (Krishi Projukti Hatboi, 9th edition, January 2020; BARI technology database), Agriculture Information Service (Krishi Kotha, February 2020 and October 2024), Department of Horticulture, BSMRAU, Tamil Nadu Agricultural University, NC State Extension, Banglapedia