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January 02, 2019 Wednesday 02:12:57 PM IST

A friend in weed Floating farms on weed islands

Cover Story

The concept of ‘hydroponics’ or ‘soil-less agriculture’ is a well-documented and widely used technique, in which plants are grown in nutrient solutions in the absence of soil.  But in ‘modified hydroponics or floating agriculture’, the idea is to cultivate plants in a bed of aquatic weeds which are floating in water.  Such ‘floating weed islands’ created using the locally available weeds are used for cultivating a variety of vegetables.  The beds of rotting vegetation act as compost for crop growth and these beds float on the surface of the water, thus creating cultivable areas suitable for agriculture within waterlogged regions.  ‘Floating agriculture’ is a way of utilizing areas which are waterlogged for long periods of time, for the production of food.  This technique is widely used in the waterlogged areas of Bangladesh and Myanmar, but has not been tried in Kerala.

In Bangladesh, more than 20 different crops including turmeric and ginger are raised on floating beds. These are alternate livelihood programmes in Bangladesh since it is a cyclone prone region.  Now this assumes greater significance in Kerala in the post flood scenario and in light of climate change.  There is great scope of adopting this technology in Kerala for multiple reasons.


The author has successfully completed a research project on this aspect at Sanatana Dharma College, Alappuzha, Kerala, funded by the Kerala State Council for Science, Technology and Environment, Government of Kerala, under the Rural Technology Programme.  The pond in the college campus was the site of the study.  Aquatic weeds, mainly water hyacinth (Eichhornia crassipes) was collected from the nearby areas in Kuttanad and allowed to rot in the water.  The weeds were taken in gunny bags and/or baskets made of reed (Panambu) and were kept immersed in water for a week.  Seeds of Ladies Finger Abelmoschus esculentus or Hibiscus esculentus, Chilies (Capsicum annuum) and Cow Pea (Vigna unguiculata) were obtained from the Kerala State Seed Supply Authority, Alappuzha.  The seeds were planted in balls made of decayed hyacinth, mixed with soil and coir pith based soil nutrient obtained from the market.  This was developed by us and gave good results.  The germinated plants were later transplanted into the floating beds.

The Cow Pea (Vigna unguiculata) seeds planted germinated and survived in the water hyacinth beds.  Their growth was normal and without any obvious problems.  There was no need to water the plants as the growth medium was moist enough due to its natural property.  However, the ‘bed’ started becoming more compact during the course of time and fresh plants were added.  Figures represent the various stages of this process.

Major benefits

Adoption of this novel method will result in the economic utilization and control of major aquatic weeds in Kerala.  The disastrous impact of the aquatic weeds on the water bodies will be minimized.  The farming method by using aquatic weeds offers employment opportunities for farmers, agricultural workers and landless people living in the vicinity of water bodies. It helps supplement the income of local communities and contributes to alleviation of poverty, apart from providing greater food security. 

By harvesting the weeds, the area covered by the weeds are cleared, thus providing a means to effectively reduce the breeding ground for mosquitoes.  The wise use of wetlands and available resources will lead to sustainable development of the area. By cultivating crops in water, it is possible to simultaneously expand fishing operations as a variety of fishes thrive under the floating weed-bed. The system will help improve the conditions for open-water fishing.  Vegetables produced on the floating beds can be sold at markets and since the approach is fully organic, the produce receives special attention from local buyers and consumers.

This is the first study on this innovative method and needs to be taken up further.  Preliminary discussion has already been carried out with farmers from Kuttanad and efforts are on to try this at a larger scale in the backwaters and waterlogged farmlands in the area.  Local panchayaths, Residents’ Associations and NGOs have joined hands to try this out in the canals of Alappuzha.  State-level initiatives are also being tried through various means.

The author has developed many innovative methods and products from the aquatic weeds, which have won recognition at various levels. (For more information,  Email

(The writer is Principal Investigator, Centre for Research on Aquatic Resources, S. D. College, Alappuzha)


The writer is Principal Investigator, Centre for Research on Aquatic Resources, S. D. College, Alappuzha

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