What to keep in mind when growing flowers: planting, care and harvest

On 30 May 2021 Jagonews24 published a practical guide for people in Bangladesh who wanted to grow flowers, on a farm plot or in pots on a roof or veranda. It said flowers were no longer grown only for beauty: they had real commercial value, and many people were becoming self-reliant by growing them scientifically in line with demand. The guide went through planting time, choosing and fencing land, preparing soil, fertiliser, care, harvest and pots. This report keeps those steps and checks them against work by the Bangladesh Agricultural Research Institute (BARI), university studies and reports available at that time. Where the guide's pesticide advice was unsafe, it is corrected.

Banglapedia traces the country's cut-flower trade to the selling of flowers at holy shrines and other places visited by devotees. Cut flowers became popular with the general public after independence, first through locally collected and imported flowers, and farmers later began growing them to supply the capital and other towns. Commercial cultivation at Godkhali in Jhikargachha upazila of Jashore began in the 1980s, and Godkhali became the country's largest wholesale flower market. The guide said roses, tuberose, marigold, rangan and gladiolus were grown commercially in several regions including Khulna and Jashore, making an economic contribution and giving many people work.

How much land is under flowers depends on who is counting. The Bangladesh Bureau of Statistics figure quoted by BARI economists was 520.64 hectares and 4,308 tonnes in 2008-09. The Business Standard reported in November 2020 that flowers were grown on about 6,000 hectares in roughly 23 districts, and that the Bangladesh Flower Society put the market at about Tk1,500 crore. A 2019 paper from Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), citing a 2018 study, gave about 10,000 hectares. For Jashore alone, the Dhaka Tribune reported about 6,500 hectares across Jhikargachha and Sharsha upazilas in June 2020, while a local agriculture officer told The Daily Star that December that about 600 hectares in six unions were under commercial cultivation. These are best read as estimates made in different ways.

The society's president told The Daily Star in December 2020 that flowers supported about 3 million people, roughly 20,000 of them directly in farming. Traders counted more than 20,000 flower shops nationwide, 800 of them in the capital. Roses made up about 35 percent of sales, followed by gladiolus, tuberose and gerbera, according to The Business Standard.

The guide appeared a year after the trade's worst months. The Godkhali wholesale market had closed on 24 March 2020 under the coronavirus shutdown, which lasted 66 days and ended on 31 May, and Cyclone Amphan struck in the third week of that May. The Jhikargachha upazila agriculture officer estimated losses there at Tk 30 crore from the virus and Tk 20 crore from the cyclone, and florists claimed a net loss of Tk400 crore nationally. Demand follows the calendar: buying starts with Victory Day in December, January to April is the peak trading season, and the big days include the first day of spring, Valentine's Day, International Mother Language Day, Independence Day and the Bangla New Year.

The guide listed rose, marigold, chameli, beli, jui, shefali, tuberose (rajanigandha), gandharaj, gladiolus, dopatti, hasna-hena, chrysanthemum, dahlia, rangan, dolonchapa, kanakchapa, aparajita, jaba, malati and kamini. Some are perennial and some seasonal; some grow on their own while others have to be cultivated.

The guide added that all of them had about equal commercial value. The market did not bear that out. Banglapedia lists rose, gladiolus, marigold, chrysanthemum and single and double tuberose as the commonly traded local flowers, with lotus a recent addition, while karobi, jasmine, kamini, water lily, dolonchapa, golden champa, dahlia and zinnia reached the market only occasionally. The Godkhali market sold marigold, rose, gladiolus, tuberose, gerbera, cosmos, gypsy, dahlia and chrysanthemum, so a new grower does well to find out first what the nearest market buys.

Variety matters as well. All 100 rose farmers surveyed by BARI in Jhikargachha in December 2010 grew Lincoln, and Banglapedia names Papa Meilland, Double Delight, Dutch Gold, Queen Elizabeth and Montezuma among the well-known roses grown in the country, usually raised by budding. In the marigold survey of Jashore and Jhenaidah in February 2011, 95 percent of farmers grew T-004, a promising BARI line. Among tuberose farmers in Jashore and Chuadanga, 88 percent grew the double type. BARI's Floriculture Division had released six gladiolus varieties by 2019, and BSMRAU tested 19 gladiolus lines collected from farmers and nurseries at Godkhali, Benapole, Jashore, Bogura and Savar; BARI Gladiolus-3 produced its flower stalk in 58.7 days.

The guide gave Ashwin to Agrahayan, roughly mid-September to mid-December, as the right time to plant the seeds, seedlings, cuttings or bulbs of most flowers. Research fits this for the winter flowers. Marigold farmers in Jashore and Jhenaidah planted from mid-October to mid-November and picked from January to May. BARI set out 30-day-old marigold seedlings at Gazipur between 7 November and 17 December in its three trial years, and gladiolus was planted on 12 November 2017 at BSMRAU and on 25 November 2006 at BARI.

Two of the main commercial flowers follow a different calendar in the field. Tuberose farmers in Jashore and Chuadanga planted in March and April and plucked from September to May, with commercial harvesting starting only in the second year. Rose growers in Jhikargachha planted seedlings or cuttings from mid-February to mid-March, and first-year gardens gave flowers from April until the next January. Temperature explains part of the winter window for marigold: the BARI paper notes that a mild climate of 14.5 to 28.6 degrees Celsius greatly improved flowering, while 26.2 to 34.4 degrees hurt production.

The guide called the choice of land very important. The plot should get plenty of light and air, high loam soil suits flowers, and a garden of suitable size and shape looks better. Cattle and other intruders are kept out with a strong fence of bamboo, barbed wire or iron, and the grower has to make sure cows and goats cannot break it.

Research on marigold describes the ideal more closely: a deep, fertile, friable sandy loam that holds water, drains well and is close to neutral, at pH 7.0 to 7.5. Soils in Bangladesh differ widely from that. Banglapedia describes the High Ganges River Floodplain in the west as mostly highland and medium highland, with calcareous, slightly alkaline soils of low general fertility, and the Madhupur Tract as strongly acidic, with low organic matter and low moisture-holding capacity. BARI's own field at Joydebpur tested at pH 6.2 with 0.95 percent organic matter and was low in most nutrients, which is why a soil test comes before any fertiliser plan.

On a large plot the guide advised dividing the land into separate areas for different flowers and planting to a plan. The land is dug well and fertiliser is applied 20 to 25 days before bulbs, seedlings or cuttings go in. It named rotted cow dung, TSP, bone meal, MoP, urea, oil cake, used tea leaves and ash, mixed in until the soil is loose and friable, and said organic fertiliser should come first. It gave no amounts.

BARI's farm surveys support the preference for manure and the caution about chemical fertiliser. Tuberose farmers used 6.53 tonnes of manure per hectare with 274 kg of urea, 268 kg of TSP and 216 kg of MoP, and the study found production fell with lower use of manure and with urea, TSP and MoP above the recommended doses. Rose growers in Jhikargachha used only 1,546 kg of manure per hectare, but 1,710 kg of urea, 1,194 kg of TSP and 592 kg of MoP, all above the recommended 1,302 kg, 1,000 kg and 400 kg quoted in the study. Marigold farmers used less urea than recommended (363 kg against 420 kg) and more TSP (342 kg against 200 kg) and MoP (231 kg against 150 kg).

Trials show what balanced feeding can do. These results were obtained on research plots, and the first two are amounts of plant nutrient per hectare, not weights of fertiliser from the bag:

• Marigold at BARI, Joydebpur, 2012-13 to 2014-15: the best yields of 22.25, 27.38 and 25.15 tonnes per hectare came from 90 kg nitrogen, 40 kg phosphorus and 90 kg potassium, with 2 kg boron and 4 kg zinc. All the phosphorus, potassium, boron and zinc and a third of the nitrogen went in at final land preparation, and the rest of the nitrogen in two equal parts 30 and 45 days after transplanting.
• Chrysanthemum in the same years: the best yields of 12.45, 11.47 and 11.96 tonnes per hectare came from 150 kg nitrogen, 75 kg phosphorus and 135 kg potassium, with the same boron and zinc.
• Gladiolus at BSMRAU, 2017-18: the plots received cow dung at 10 tonnes per hectare, urea 300 kg, TSP 375 kg, MoP 300 kg, boric acid 12 kg and zinc sulphate 8 kg. All but the urea went in at final land preparation; half the urea followed 25 days after planting and the rest as the spike formed.

The BARI authors recommended their marigold and chrysanthemum doses only for the Grey Terrace soil of Joydebpur, and the marigold paper cites work showing that high nitrogen can reduce the yield of flower heads. A BARI gladiolus paper noted that growers had no recommended dose for producing corms, and that some multiplied their corms with no chemical fertiliser at all. A grower elsewhere should take these figures as a guide to balance and ask the upazila agriculture officer for the dose that suits the soil and the flower.

The guide's rule was to plant only healthy, disease-free seedlings or bulbs. After planting, press the soil firmly at the sides rather than on top, water as needed and, depending on the plant, drive in a stake and tie the seedling to it. BSMRAU's work shows why staking matters: tall gladiolus tends to lodge and needs support, and BARI Gladiolus-5 reached 92.3 cm.

Every farmer in the BARI surveys of tuberose, rose and marigold planted in lines. Rose growers used 7,304 seedlings or cuttings per hectare. Trial spacing was 50 cm by 40 cm for marigold, while BSMRAU planted medium gladiolus corms of 3.5 to 4.5 cm about 6 to 9 cm deep at 30 cm by 15 cm. These were research layouts rather than official recommendations.

The guide said good nurseries in towns and villages sold improved seeds, cuttings and seedlings, and that seedlings could also be had through the agricultural extension office. That advice speaks to the problems farmers themselves reported: in all three BARI surveys, lack of technical knowledge and of high-yielding seedlings ranked among the main constraints. BARI scientists also named a lack of quality planting material as one reason gladiolus yield and quality fell short. Banglapedia notes that micropropagation of roses was not yet commercially viable in the country.

Care, the guide said, means pulling weeds, loosening the soil around the base from time to time and irrigating when needed. Balanced fertiliser and water are given in several rounds as the plant requires, and special care starts well before flowering, with an eye on both the number and the quality of blooms. Old and diseased branches are pruned according to the plant.

The surveys show how much work that is. Tuberose farmers averaged 10 weedings and 11 irrigations, marigold farmers 5 weedings and 7.5 irrigations, and rose farmers 18 weedings and 19 irrigations. Labour came to 571 person-days per hectare for tuberose, 416 for marigold and 726 for rose. In its marigold trials BARI weeded three times and watered every 7 days until harvest.

Pruning also sets the harvest calendar for roses. In Jhikargachha, 70 percent of farmers pruned from mid-October to mid-November and picked from January to September, while the other 30 percent pruned from mid-February to mid-March and picked from April to the following January. BARI's authors put the difference in harvest time down to this difference in pruning.

The 2021 guide suggested Heptachlor-40 against ants and spiders, and malathion or Dimecron for common insects. Two of those names should not be followed. Heptachlor is one of the 12 original persistent organic pollutants, listed for elimination in Annex A of the Stockholm Convention, which Bangladesh signed on 23 May 2001. WHO lists it as obsolete, and the Environment and Social Development Organization (ESDO), a Bangladeshi group, reports that it was banned in the country in 1996. Dimecron is a trade name of phosphamidon, which WHO's 2019 classification places in Class Ia, extremely hazardous, and which ESDO lists among the pesticides the government has banned. Malathion is in WHO's Class III, slightly hazardous.

Under the Pesticides Act 2018, every pesticide brand has to be registered before it is imported, made or formulated. A grower should use only a currently registered product for the flower and pest in question, as the label directs. This report gives no pesticide doses; the upazila agriculture officer can advise on them.

Spiders are not a pest of flowers. University of California integrated pest management guidance describes them as predators that are mostly beneficial because they feed on pest insects. The small creatures that do harm leaves are often spider mites, which are not spiders. They suck the leaf cells, leaving pale stippling and fine webbing, and do worst on water-stressed plants. Keeping plants watered, spraying the undersides of leaves with a strong jet of water and avoiding broad-spectrum insecticides, which kill the mites' predators, all help.

Ants matter mainly because they protect aphids from natural enemies and feed on their honeydew. The same guidance advises checking plants often, pruning infested shoots, knocking aphids off with water, avoiding excess nitrogen and sparing the lady beetles and lacewing larvae that eat them. For roses in humid conditions it lists black spot, downy mildew and botrytis among the diseases, and advises spacing plants, pruning for air movement, watering so that leaves dry before evening and clearing fallen leaves. At BSMRAU, leaf blight and cutworm appeared on some gladiolus lines. The guide's own line was to treat each disease according to what it is.

Spraying is already a large cost. Rose farmers in Jhikargachha sprayed insecticide 16 times on average, at Tk 55,200 per hectare or 14 percent of their cost, and still named insects and diseases as a major problem. Bangladesh has worked with integrated pest management since joining the FAO's inter-country programme in 1981; between 1988 and 1995 it trained 2,257 extension workers, 407 NGO officers and 4,550 farmers, and trained rice farmers used pesticide less than their neighbours, as a last resort.

The guide said flowers can be cut with their stalks before they fully open, and that standing the lower part of the stalk in water keeps them fresh. To hold their quality, the stalked flowers are tied in neat bundles, wrapped in black polythene and sent to market.

Gladiolus shows how exact the timing can be. BSMRAU cut spikes when the lowest one or two florets showed colour but were still in tight bud, and these lasted about 8 to 9 days in a vase for BARI Gladiolus-3 and up to 9 to 11 days in the best line. Corms were lifted once the leaves turned brown. At Khulna University, a 2003 study on tuberose and gladiolus found that stems pretreated for 24 hours in 2 g of citric acid and 40 g of sugar per litre performed best, and that the source of the water made no significant difference.

Getting flowers to town is often the weakest link. In the BARI marigold survey, 65 percent of farmers raised transport as a problem, and tuberose farmers ranked it third among their constraints. The study's authors called for quicker transport and proper storage to reduce spoilage.

The BARI surveys give a picture of the returns about a decade before the guide, and they cover only the farmers interviewed:

• Tuberose, January 2010: 454,425 sticks per hectare, a full cost of Tk 200,761 and a net return of Tk 480,876, which the authors found 65 percent above banana and 71 percent above papaya. The benefit-cost ratio on full cost was 3.39.
• Rose, December 2010: 540,107 flowers per hectare at a full cost of Tk 387,569, with a benefit-cost ratio of 1.63 on full cost.
• Marigold, February 2011: 2,650,447 flowers per hectare at a full cost of Tk 147,234, a net return of Tk 117,812 and a ratio of 1.80.

In December 2020 The Business Standard reported production costs per acre in Jashore of about Tk36 lakh for gerbera, Tk4.5 lakh for roses, Tk4 lakh for gladiolus, Tk2.5 lakh for tuberose and Tk2.30 lakh for marigold. That month a hundred tuberoses fetched Tk 200 to 250 at Godkhali, and one grower sold winter roses at Tk4 each for a marginal profit.

Where land is short, the guide said, flowers can be grown in pots on rooftops and verandas, as a hobby or for sale. It named roses and marigolds of many varieties and colours, dahlia, rangan, chrysanthemum, tuberose, orchids, attractive cacti and bonsai, and said all had good demand. To save time, it suggested annual or permanent plants such as rose, jaba, cherry, dolonchapa, malati, kamini, rangan, patabahar (croton), orchids and cacti. Cactus-type plants need very little fertiliser, so they cost little to keep.

Rooftop growing already had a following in Dhaka. A Stamford University survey of 2,700 buildings in Dhanmondi, Lalmatia, Mohakhali DOHS and Uttara found 36.4 percent of rooftops used for gardening, The Daily Star reported in April 2019, and the non-profit Green Savers had set up 3,600 rooftop gardens across the city. The two Dhaka city corporations gave a 10 percent holding tax rebate for rooftop gardening in the first quarter of fiscal years 2016-17 and 2017-18.

Orchids deserve care in buying. Banglapedia counts roughly 200 native species, flowering mainly from January to July with a peak in March and April, and says local nurseries sell native orchids alongside exotic ones. It also warns that some epiphytic species are at risk from habitat destruction and excessive collection, so buying plants raised in nurseries avoids adding to that pressure.

Photo: SharierKabir / Wikimedia Commons (CC BY-SA 4.0). The top picture shows gerbera beds at Godkhali, Jashore, in February 2021, as background.

Sources: Jagonews24 (30 May 2021), Bangladesh Journal of Agricultural Research (BARI studies of tuberose, marigold, gladiolus and rose, 2012-2013), The Agriculturists (BARI marigold and chrysanthemum trials, 2017), Annals of Bangladesh Agriculture (BSMRAU gladiolus study, 2019), Khulna University Studies (2003), The Business Standard (17 November and 16 December 2020), The Daily Star (18 April 2019, 13 April and 7 December 2020), Dhaka Tribune (17 June 2020), WHO Recommended Classification of Pesticides by Hazard (2019), Stockholm Convention, IPCS INCHEM, ESDO, Pesticides Act 2018, University of California Statewide IPM Program, Banglapedia