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Charlie Parker


"I can't think of any technology that addresses more urgent issues than Valcent's vertical farming system", says RFK Jr http://bit.ly/cPb00g



It's a great concept. However, I can't find any actual tutorials from Van Cottem for creating a vertical, urban indoor garden.
For apartment renters, we'd need something easy to install in a variety of different wall types, something that would not have floating columns of water (likely to break, ruin the carpet, and take away our entire security deposit), and something easy to install and take down when moving. In first world urban areas, materials and even cost of such a system aren't the problem--it's time, technology, space, and cleanliness.

Kris De Decker


Van Cotthem does not give conveniently arranged step-by-step instructions, that's true, but if you follow the links above and read the stuff I think you know all you need to know to create an indoor garden. (and this link above comes very close to a tutorial, no? http://containergardening.wordpress.com/2007/08/14/gardening-ideas/ )

Not sure if the thing you are looking for will ever be possible, though. I mean, water will always be needed to grow food. And in this respect, his system seems to score better than the window farms.

levi civita


Plastic containers are problematic due to their chemical make up. http://www.energybulletin.net/node/51955

Use earthenware when practical.

Willem Van Cotthem


See (2)- Thanks for the appreciation, Amy. You are completely right: the description of the bottle rack I had in mind is for outdoors use, in particular in the drylands where water saving is a priority in horticulture. Therefore, I suggested to let the water percolating through the upper rows of bottles run into the row underneath. Of course, this can't be done indoors. However, I described another variant which can be used indoors too (inverted bottle in water tank). If the rack would be made of a transparent plastic plate, it could even be installed on a windowsill. With a bit of imagination one can develop variants for particular situations.

Willem Van Cotthem


See (3) - Sincere thanks, Kris. We will try to regroup the postings on my blog to make it less chaotic (in the meanwhile one can use the "categories" in the column at right hand side). At different occasions I described variants of bottle gardening, mostly to produce a maximum of biomass with a minimum of water. My preference still goes to "the inverted bottle in its water tank" (see my 2007/09/18 posting: Plastic bottles and bags: precious jewels for container gardening) on my containergardening blog. Herewith almost no single drop of water is lost and plant care is minimal. Just try it yourself.

Willem Van Cotthem


See (4) - I thank Levi Civita for this remark on the problems of the chemical make up of plastic containers. As a biologist, I agree fully with experts alerting us for the threats of certain components in certain plastics. But I don't agree with the overall doom scenario written by some journalists. Moreover, I don't believe that "dangerous" plastics will disappear within the next decades. They will slowly be replaced by "less dangerous", e.g. biodegradable ones. In the meanwhile, we are recycling some in the developed countries and the bulk of plastics is simply going to waste dumps where we cover it all up with a good top layer of soil.

However, in the developing countries most plastic objects are finally littered. Pots, bags and bottles are literally covering the streets or hanging in the trees as plastic flowers. That dirt causes more diseases than the plastics themselves, e.g. by being the preferred niches for a panoply of germs on the spots where the kids are playing in the dirt. "Recycling" plastic bags, pots and bottles by using them as containers for production of vitamin rich vegetables or seedlings of fruit trees is less dangerous than leaving them flying around in the environment. I agree with Levi that wealthy people, who can afford buying earthenware or glassware for gardening, shouldn't use the plastic trash. But for the poor people and school children in developing countries, gardening in plastic bottles is not only a contribution to food security, but also to public health. And it helps to keep the environment a bit cleaner and greener, particularly in the drylands.

Kris De Decker


Willem, thanks for your replies.

Concerning the chemical make up of plastic containers: sure, nothing new here. But, nearly all our food is packaged in plastic, and many food crops are grown in plastic containers, too (even in high-tech vertical farms http://www.valcent.eu/ ). Fish eat microscopic plastic that we throw in the seas, and we eat fish. And these are just some examples of plastic pollution.

Health risks due to chemicals in plastic don't seem to be a specific problem of the low-tech farm described above.

Secondly, I think it is telling that people make a distinction between technology intended for the rich world, and technology intended for the poor world. No problem if the poor grow their food in plastic trash containers. But when it comes to ourselves, we demand ceramic containers.

I am not sure why we are entitled to use extra resources and energy to produce ceramic containers (producing toxic substances in the process), while they can use the trash that we have produced (it's not African companies manufacturing plastic bags). Why not the other way around?

Also don't forget that a large part of the rich world is depleting its underground fossil water reserves at an alarming pace, the USA being a good example. The poor drylands that Van Cotthem originally designed his method for, might not be that far away:




If you are looking for a source of containers I recommend visiting your local restaurants and ask them for their empty glass jars. Some (such as the ones that hold pickles or sauces) hold more than 3 litres (0.8 Us Gal).

plastic soil?


The containers in Professor Van Cotthem's may not be low-tech at all but they merit something for the reuse of otherwise harmful trash. That's the least problem. What's the story with this trademark TerraCottem soil supplement??? The professor invented it, so his promotion of his proprietary product is understandable, but there's nothing low-tech about it. This product is described on www.terracottem.com as "consisting of a proprietary mixture each [sic.] of more than twenty components from different groups..." and the product's "crosslinked hydroabsorbent polymers of acrylamide and acrylic acid..." that's before saying anything about this medium's "carrier materials."

I don't understand half of this description. I only understand enough to say this is a high-tech product that one can only buy, not make at home.

Additionally, what with the polymer talk it sounds like plastic soil. Surely that's far worse and dangerous than the mere containers.

Does this plastic soil degrade? How long does that take? What are the fertilizers in it? More petrochemicals?

kris de decker


"What's the story with this trademark TerraCottem soil supplement???"

I don't get that either. That's why I left it out.

Mark Ridsdill Smith


Really interested to read about this. Is there anyone out there who has built one of these and is using it to grow food? Or plans to build one? If so, I'd love to hear about your experiences.

These bottle containers are clearly designed for food growing in countries with little water and I'd have thought the bottles are rather small (and fiddly) for productive food growing elsewhere? Other ideas like like this look more fit for for purpose: http://www.urbanorganicgardener.com/self-watering-containers/how-to-make-a-self-watering-container/

Mark (www.verticalveg.org.uk)

Kris De Decker


Interesting blog you have, Mark


Willem Van Cotthem


I appreciate the suggestion of "Observer 23" (#9) to use glass jars as containers for growing plants. However, be aware of the difficulty to drain the potting soil, when standing water in the jar can provoke acidity and development of fungi. Therefore, I prefer plastic containers (bottles, pots, bags). I perforate them twice at 2-3 cm above the bottom in order to keep a bit of irrigation water in the container, whilst evacuating the surplus through these little holes in the container wall.

Willem Van Cotthem


# 10 (Plastic soil) - High-tech, low-tech, no-tech? Are we heading for a discussion on semantics? What's in a word? The main objective of my search for simple ways of saving water when producing food crops in the drylands is to use cheap and simple materials, affordable for the poor local people. If these "low-tech" solutions are also applicable in the developed world, it's a "win" situation. Reusing otherwise harmful trash to help these hungry people to fresh food is partly solving a couple of the major world problems: hunger and child malnutrition.

The story of the TerraCottem soil conditioner is a completely different one. Yes, I am the inventor of this "high-tech" product but, for deontological and legal reasons, I am not involved in its marketing. Even if the scientific description of its content may seem very complicated to non-scientists, its general description makes the things very clear: it is a soil amendment to enhance the soil's water holding capacity and its nutrient content. It improves root growth and aeration of the substrate. The overall result of its application is: more plant production with less water. It's that simple, like the many other simple products we are only buying, not being able to make them ourselves at home or even to understand their composition.

It is not because the word "polymers" SOUNDS LIKE PLASTIC SOIL, that they ARE plastics! This sounds like "jumping to conclusions".

Finally, I don't think this Low-tech Magazine is the right forum to discuss the composition of a "high-tech" soil amendment, which has been developed to offer poor people in the drylands a chance to grow some food in their harsh environment (with external support, of course).

Willem Van Cotthem


See (11) - Dear Kris, I just read the article above again : "How to make your own low-tech vertical farm". Did I miss the word TerraCottem somewhere in the text ? Did you (the author of that text) made any allusion on my former scientific work on soil conditioners ?

Let us not mix apples and lemons. This idea of growing plants in plastic bottles on a vertical rack is only one of the results of my continuous efforts to help hungry people in the drylands to fresh food with a minimum of water.

I remain open to any discussion on TerraCottem, but not in your excellent Low-Tech Magazine, because that soil conditioner is most certainly NOT LOW-TECH.

G L Bansal


The idea is great and makes sense for growing freshies and vegies at home scale in little containers. It is more of hype than reality in use of plastics as pointed out. Sometimes ago, there was controversy over use of plastics in microwave ovens and there were divergent views. I think people may be affected more for the want of freshies and nutritional deficiencies than plastics. The produce is well balanced and without pesticides.



A small fish tank air pump could be used to slowly lift the water to the top. Here is an example.




Actually this year starting with window farming, I didn’t get into vertical farming yet, but having some success in sprouting and growing different kinds of peppers (bell, Chinese, lombok). The problem with vertical farming is the noisy aquarium pump and the fact that it wouldn’t do without electricity. The VanCottem setup inspired me to think of a passive pump system, bio clock like. Plants don’t only grow, but do become heavier while growing, and do need more nutrients. Actually the pump should work slow in the beginning and work harder (and make more noise) when it gets more leaf. A classic clockwork has a counter weight that actually makes the clockwork work (timed). A plant with a certain start-up weight could do as a counter weight, driving a clockwork like mechanical pump while growing upwards, becoming heavier and leafier. It would mean having only one plant vertically, and several horizontal. The pump would be a silent one, without the use of electricity.



Actually, the roots are very sensitive to light. So the plastic bootles should be painted black.

Moshfequel Alam


Thanks for lovely initiative

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