Floating gardens
Practical Action
Although floating gardens have been successful for many people there are some who cannot
make use of this farming technique. Some of the landless poor do not have access to areas
where the gardens could be set up. Even when areas of water are available they can be some
distance away from the household. Another difficulty that can arise is that the raw materials
to make the raft may not be available.
Gardens are relatively inexpensive to make requiring a small investment in fertiliser and seeds
as well as the labour needed to construct them. Other materials such as the aquatic weed for
the base of the raft can be obtained locally at no cost.
The base of the raft is often made from water hyacinth, which is a common weed in many
parts of the world where it clogs up water systems and damages the ecosystems and
aquaculture within ponds. It is better to use mature water hyacinth as green water hyacinth
will decompose too quickly and the raft will not survive the growing season. If water hyacinth
is not available other materials can be used such as paddy straw, nalkhagra – a freshwater
wetland tree, and any available organic materials such as azola, coconut straw, bamboo, and
old rope.
There is no fixed size of raft. Commonly, the rafts are around 8m long and 2m wide and are
around 0.6 to 1m deep. The size of the raft can be made to suit the circumstances of the
user. If there is a lack of space or if raw materials are in short supply then the rafts can be
made smaller.
Creating a floating garden
The first step to making a floating raft
is to collect the water hyacinth.
Floating water hyacinth is overlaid with
bamboo poles of appropriate length to
the size of the raft being constructed
and this mass of plant matter is taken
to one bank to be worked on.
Additional water hyacinth is collected
with stick hooks and placed onto the
bamboo layer and the thickness of the
raft is built up. It is then woven into a
buoyant raft.
Once the raft’s basic structure has
been created the bamboo poles can be
pulled out.
Figure 3: The garden begins to take shape. Photo
credit: Practical Action Bangladesh.
After around 7 to 10 days more water
hyacinth is added to top up the
existing structure then a mulch can be
added on to the water hyacinth base.
Soil, compost and cow dung are added
to cover the base of the raft to a depth
of around 25cm. The compost is made
up from azola, a good nitrogen fixing
plant, and other readily available
organic matter.
Seeds can then be sown. The
technique used to improve the seeds’
Figure 4: The floating garden with its earth layer.
Photo credit: Practical Action Bangladesh.
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