Living tunnel greenhouses for food production



Building living tunnel greenhouses for rural people in the drylands

Originally published at:

By Prof. Dr. Willem VAN COTTHEM

University of Ghent, Belgium

One of the biggest problems for sustainably constructing greenhouses in the drylands is that of the strong winds.  Most of the existing greenhouse constructions in developing countries do not resist these winds and the recurrent need to invest in reparations discourages those who see greenhouses as a valuable tool for sustainable economic development of the local people.

It is my sincere conviction that a good solution for this problem can be found in switching from man-made constructions with greenhouse frames (metal or bamboo) to “living greenhouses” with poles (stems) of growing trees.

In every single region on earth one can find (or introduce) easily rooting tree species.  For some of them it suffices to directly planting cuttings in the local soil to get these cuttings rooting and developing after a while.  One of these trees species is the Chinese willow (Salix matsudana) of which a number of varieties are grown all over the world, even in the desert, e.g. the Navajo willow (Salix matsudana var. Navajo), growing in Arizona.

Having in my garden in Belgium a couple of these willows, I developed the idea that with some cuttings I could “construct” a long living, sustainable “teepee”.  Within a very short period such a shady little tent (a greenhouse) was grown:

Some branches of the Navajo willow planted in the form of a teepee (Photo WVC 2011-02 – P1050821)

The 3 meter long branches, used as teepee poles, soon developed numerous lateral branches, some of which were cut off and planted nearby to produce new poles for a second, a third, a fourth, … teepee in the future.

Only 4 months later the teepee became a shady place to hide for the burning sun (Photo WVC 2011-06 – P1060817)

It goes without saying that cuttings of this Chinese willow can also be planted in two lines, e.g. over a distance of 50 meter with a cutting every 50 cm, to form a tunnel greenhouse.  One can easily let these willow cuttings quickly grow into a young tree, pruning them into vertical poles.

Once these poles in the two parallel lines are high enough, one can bend them towards each other and bind their tops to form a “living tunnel”.  Lateral branches, reaching a length of e.g. 30 cm, are pruned, except those in the plane of the tunnel walls.  One can even “weave” these lateral branches into a strong network.

The canopy of the tunnel is filtering the heavy sunlight and air humidity inside the tunnel is higher, due to the transpiration of the leaves. These natural conditions (shade and humidity) are most profitable for growing plants, e.g. vegetables and/or herbs inside the tunnel.

Willow tunnel - Photo Avantgardens - 483952_622321094448322_553292267_n
A young willow tunnel – Photo Avantgardens – 483952_622321094448322_553292267_n.jpg
Willow tunnel - Photo Avantgardens - 575749_621090494571382_833796101_n
Inside a willow tunnel – Photo Avantgardens – 575749_621090494571382_833796101_n.jpg

Living tunnels can be used as a nursery for the production of hundreds (if not thousands) of saplings from cuttings. But they can also be used as a shady kitchen garden in which numerous food crops can be grown in containers, e.g. in bottle towers (see<;) with less water than the volume of irrigation water normally used on open fields, with irrigation in the morning and the evening.  

Once a single living tunnel greenhouse exists in a location the construction of new tunnels is unlimited.  It suffices to make the right choice of a tree species that is adapted to the local environmental conditions, easily rooting and developing relatively quickly.

The Chinese willow (Salix matsudana) is one of those species easily adapting to different types of climate.  I got mine from the drylands in Arizona and it is growing remarkably well in Belgium.  My 2 cuttings (30 cm in 2003) are now in 2016 12-14 meter high !   I would recommend to use the Navajo variety of this Chinese willow (Salix matsudana var. Navajo), a drought-tolerant variety growing in desert-like circumstances, only needing a minimum of water.

Anyway, whatever the tree species chosen (preferably an easily rooting local one), I am quite sure that it must be feasible for all the rural people on earth, to set up their own “living teepee” or their “living tunnel greenhouse”. The choice is theirs.

It would be a fantastic tool to combat malnutrition or hunger.

Please have a look at my video:

“No more plastic greenhouses or tunnels needed : grow your own live greenhouse (a tipi/teepee or a tunnel) with branches of the drought-tolerant Navajo willow, also globe willow, or the Chinese willow (Salix matsudana). One can grow these willows with a minimum of water in the drylands, even in the desert.

Such a live greenhouse offers remarkable advantages : natural shade and higher air humidity inside because of the transpiration by the leaves.

In drylands or deserts people can easily grow plants, e.g. young fruit trees and vegetables, inside the greenhouse, which can also offer shelter against the sun heat.

Outgrowing branches of the willow can be pruned to construct progressively new greenhouses.”

Solar greenhouses to save energy

Photo credit: WVC 1995-1999 – Picture5-Gao-Jia-Van-02b.jpg

Belgian TC-Dialogue Foundation’s Greenhouse project in the Lanzhou region (Gansu Province, P.R. China 1995-1999)

Reinventing the Greenhouse

The modern glass greenhouse requires massive inputs of energy to grow crops out of season. That’s because each square metre of glass, even if it’s triple glazed, loses ten times as much heat as a wall.

However, growing fruits and vegetables out of season can also happen in a sustainable way, using the energy from the sun. Contrary to its fully glazed counterpart, a passive solar greenhouse is designed to retain as much warmth as possible.

Research shows that it’s possible to grow warmth-loving crops all year round with solar energy alone, even if it’s freezing outside. The solar greenhouse is especially successful in China, where many thousands of these structures have been built during the last decades.

Read the full article: Low-Tech Magazine

You can do it with fruit walls

Photo credit: Low-Tech Magazine


Fruit Walls: Urban Farming in the 1600s

We are being told to eat local and seasonal food, either because other crops have been tranported over long distances, or because they are grown in energy-intensive greenhouses. But it wasn’t always like that. From the sixteenth to the twentieth century, urban farmers grew Mediterranean fruits and vegetables as far north as England and the Netherlands, using only renewable energy.

Montreuil peachesThese crops were grown surrounded by massive “fruit walls”, which stored the heat from the sun and released it at night, creating a microclimate that could increase the temperature by more than 10°C (18°F).

Later, greenhouses built against the fruit walls further improved yields from solar energy alone. It was only at the very end of the nineteenth century that the greenhouse turned into a fully glazed and artificially heated building where heat is lost almost instantaneously — the complete opposite of the technology it evolved from.

Continue reading “Fruit Walls: Urban Farming in the 1600s” »

‘Bubble-Greenhouses’ turn salt water into fresh water

Photo credit: SciDevNet

Copyright: Carolyn Drake/Panos

Bubble desalination latest effort to boost crop growth


“We believe that the concept is applicable to arid regions worldwide.” Mario Schmack, Murdoch University

by Ian Randall

Speed read

  • Low-tech ‘Bubble-Greenhouses’ turn salt water into fresh water
  • They also create cool, humid conditions for better growth
  • Researchers are seeking partners to make prototype

Researchers in Australia are seeking to build a prototype ‘Bubble-Greenhouse’ that could provide remote, arid places with a low-tech, low-maintenance way to turn salt water into fresh water to grow food.

The engineers from Murdoch University, who published their study last month in the journal Desalination, estimate that a 150 square metre Bubble-Greenhouse could produce around eight cubic metres of fresh water and up to 30 kilograms of crops each day. The sealed structure would protect crops from insects and disease, while the technology should be relatively simple to implement and use in isolated areas, they say.
The Bubble-Greenhouse idea develops an existing seawater greenhouse concept, which uses the evaporation and condensation of salt water to produce fresh water for irrigation and to create a cool, humid environment inside a greenhouse, meaning crops need less water to grow.

The new approach moves the evaporation and condensation processes outside the greenhouse. Inside two water-filled ‘bubble columns’, streams of thousands of tiny bubbles create a large surface for water to evaporate or condense. A unique property of seawater prevents the small bubbles joining to form big bubbles, thus maintaining a large surface area.

Read the full article: SciDevNet

The living greenhouse farming technology

Photo credit : Inspiration Green – Sanfte Strukturen.jpg

A willow “palace”

Poor farmers can’t afford a plastic greenhouse

by Willem Van Cotthem (University of Ghent, Belgium)

I have read with great attention the article on “Greenhouse farming takes root in Kisumu” (
The greenhouse project in Kisumu (Kenya) –

It goes without saying that greenhouse farming technology is so dramatically expensive that individual poor farmers, who should be the first beneficiaries, can never afford it, unless they find some wealthy donors.  About this Kenyan project one reads:

Ngar is a member of a 19-member group which owns two greenhouses, water harvesting facility and afforestation project. He says the group started farming in 2014 and invested Sh1 million for the greenhouses measuring 18 by 30 metres with seven lines of tomatoes. The money was given to them by the Lake Victoria Environmental Project. They are also expecting further funding for the construction of water pans in readiness of farming diversification. The group bought two greenhouses at Sh155,000 each and another Sh100,000 was used for setting up an irrigation system. “We spent Sh50,000 on seeds and Sh150,000 on fertiliser and other farm inputs alongside land preparation,” Ngar said “.

A teepee made with will;ow cuttings - * Willow - Photo Nicola Stocken - wpid2482-Living-Willow-Structures-GWLL002-nicola-stocken-300x400.jpg
A teepee from willow cuttings – Photo Nicola Stocken – wpid2482-Living-Willow-Structures-GWLL002-nicola-stocken-300×400.jpg

According to the article, the greenhouse farming technology “has changed the lives of more than 100 farmers in the sub-county since inception of the project.  Residents and students have been trained on greenhouse technology, growing tree seedlings, dairy farming, biogas production, poultry farming, beekeeping and fish farming. The aim is to equip the community with skills that will help them create wealth and make them food secure”.

A willow dome - * Willow - Photo Les Urbainculteurs - 1546431_638625656194311_767877958_n.jpg
A willow dome – Photo Les Urbainculteurs – 1546431_638625656194311_767877958_n.jpg

I must confess that it is not very clear to me how the plastic greenhouse farming technology is related to the training of residents and students in “dairy farming, biogas production, poultry farming, beekeeping and fish farming.”.

A willow tunnel - * Willow - tunnel - Photo Avantgarden - 29629_830307400316356_4093777_n.jpg
A willow tunnel, the start of a shady space –  Photo Avantgarden – 29629_830307400316356_4093777_n.jpg

On the contrary, I agree fully with Kisumu’s governor when he said “Our farmers should not only farm hard but farm smart; some farmers lose their land after taking loans due to poor farming methods.  They should adopt the latest farming techniques”.

A willow hut - Photo Avantgardens - 1011887_657028324310932_418781999_n.jpg
A willow hut – Photo Avantgardens – 1011887_657028324310932_418781999_n.jpg

Well, if it seems extremely difficult, if not impossible, to find sufficient financing to offer all the poor farmers the described greenhouse farming technology (with plastic greenhouses and irrigation systems), there is maybe a remarkably low-cost solution: I call it the “LIVING GREENHOUSE FARMING TECHNOLOGY”.

casetas de sauce vivo arquitectura de sauce salix.jpg
casetas de sauce vivo arquitectura de sauce salix.jpg

This technology consists of growing “living tunnels” with quickly growing tree or bamboo species.

It is quite well known that living structures (teepees, domes, tunnels, …) can be grown from cuttings of certain tree and bamboo species (see photos).  Generally, these are only ornamental structures or “playgrounds” for children.  But this is only one step away of concluding that similar structures can easily be adapted to an almost permanent use as greenhouses.

All kinds of willow structures are feasible - Photo Avantgardens - 6943_657037390976692_1869369885_n.jpg
All kinds of willow structures are feasible – Photo Avantgardens – 6943_657037390976692_1869369885_n.jpg

Planting two rows of rooted cuttings at a distance of e.g. 3-5 meter over a length of e.g. 25 meter, letting these cuttings grow to a height of e.g. 5-7 meter, then bending the young trees (or bamboos) over and binding them into the “roof”, would create an almost indestructible “living tunnel”.

Inside such a tunnel there will be shadow from the tree leaves and air humidity because of tree transpiration.  It will be a fantastic space to work in.

Farming in a living greenhouse can be made affordable for every individual poor farmer.  It suffices to provide the necessary rooted cuttings for a first “living tunnel”, after which the farmer himself can grow his own second series of rooted cuttings by pruning now and then the trees of his first greenhouse.  Etc.

It isn’t just a nice idea: let’s go for it!

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