Vertical Greenhouse

The Vertical Greenhouse Purpose:

Intensive food production from a small footprint that produces more nutrients, clean energy and pure water that it consumes in operations.

Life Synthesis is applying the concept of the Vertical Greenhouse to create a product called Agri POD, which is intended to strengthen the Family Farm and create opportunity for household and community based social enterprise. The Agri POD will be accessible as a DIY Kit and will provide a commercial focus to the Sola Roof Coop. Additionally a group in Norway, in cooperation with CARE Norway intend to explore the use of Agri POD for sustainable development with an initiative to establish SE Net in Africa (SE Net Africa?).

Below is an illustration of the Agri POD (design with Bruce Edgar, of Phoenix Planning Design AS, Norway) AgriPOD PDF (1.05 Mb) Δ

THE VERTICAL GREENHOUSE The Vertical Greenhouse (the "VG") both amplifies sunlight reaching the leaf canopy and modifies the quality of solar radiation to provide maximum potential for plant and algae photosynthesis. More diffuse light in the PAR spectrum is produced that can penetrate the leaf canopy deeply while removal of substantially all solar IR reduces the overheating of the Controlled Environment while regulating temperature and humidity and heat loss/gain with low-energy Sola Roof technology. There are two distinct strategies for the best practices with VG systems, which are due to two possible locations for VG operations: 1) temperate to high latitude and 2) tropical to sub-tropical latitude - lets consider each of these and then go to some general implications of the VG technique.

BACKGROUND: The VG has emerged as a concept with decades of thought, work and practice in the northern latitude countries, where I developed and put into practice the Sola Roof technology. Sola Roof has a natural utility for improvement of the concept of a greenhouse, however as inventor I was pre-occupied for decades with the goal of the use of Sola Roof by the large scale commercial greenhouse industry who have extensive, horizontal roofs that are typically one or several hectares in area (for example, the Venlo greenhouse in Holland and several nordic countries). But since 2000 I have begun to place a priority on the application of Sola Roof to small scale Tunnel Greenhouse designs that can be used by households, homesteaders and the family farmer who can benefit from a small scale Sola Roof design.

Therefore, as a result of my own backyard projects of the early 1990s and my small scale prototyping starting in the late 1970s, I produced a design for Sola Roof tunnel greenhouse construction, which was put up on the internet at about 2000 - and shortly after I dedicated my Sola Roof patents to Open Source use under a Creative Commons Public License, which provides a framework for collaboration by our global community, including DI Yers.

1) temperate to high latitude

Over many years the Sola Roof greenhouse projects operated in north latitudes have been described through Open Source publication at the Sola Roof Wiki and other websites and knowledge was shared about of the ability of Liquid Bubble Insulation in the north wall of a tunnel greenhouse to act as a "light scoop" on winter days. However this benefit of the Sola Roof greenhouse has never been studied to determine the extent of the light amplification, nor has there been an attempt to study how to maximize this benefit by changing the geometry of a standard greenhouse. I have shared typical designs for Sola Roof DIY, such as the "nordic greenhouse", which is a Tunnel Greenhouse structure with a peaked ridge that is higher than the usual "Hoop Tunnel?" which uses frames of constant arc, usually called a barrel arch shape. The "Nordic Tunnel?" with its peaked shape is adopted for purpose of shedding snow from the structure but also has a recognized benefit for the winter amplification of light.

Now I propose a VG tunnel structure with arches that have a radius of the width of the greenhouse, which creates an equilateral geometry to the frame, where the vertex of the roof peak in relation to the opposite outside edges of the floor, layout an equilateral triangle in cross-sectional view of the VG. This geometry, which is shown in drawings on the Tunnel Greenhouse page, produces an unusually high peaked tunnel compared to the barrel arch of the Hoop Tunnel?? or the Nordic Tunnel??. This is a new, simple geometry for for a VG with walls of a curvature that, during northern winters, will best transmit direct solar through the transparent sun-facing side, and and concentrate diffuse light bouncing off the opposite side, which has a Bubble Cavity that is filled with Liquid Bubbles, thereby flooding the vertical growing area of the VG with maximum diffuse light. The VG is ideal for Family Farm greenhouses, where limited space available and where a large area structure is not the goal.

The design approach is to build a greenhouse that has an unusual height for its footprint. This vertical height presents a large face, or "solar aperture" to the sun in northern latitudes where it faces solar south to allow a maximum of insolation at the low solar angle of the sun approaching and following the winter solstice and therefore, during this period of reduced sunlight, there is a strong amplification of light intensity providing as much as twice the light as would normal to a conventional greenhouse having the same footprint.

This benefit is also obtained during the morning and evening of any day, during which periods of the day the low sun angle is similar to the mid-day extremes of the winter. Sunlight amplification can even come from the low angle "north sun" or mid-night sun in the northern latitudes. In this case it is the north face of the VG that captures an increased light transmission into the greenhouse during long mornings and evenings before and following the Summer Solstice. The total picture for the mid to high latitude locations is an increase in light that is very substantial and this makes the VG potentially twice as productive as the typical low profile tunnel greenhouse. During cloudy days these strategies are much less effective and the best practice is to keep the glazing Bubble Cavity empty (of Liquid Bubbles) and get maximum light into the greenhouse from the entire sky.

The use of Sola Roof technology to sustain Liquid Bubbles in the face of the greenhouse that is opposite to the sun-facing-side is a technique to maximize the resulting amplification of sunlight within the VG. The Liquid Bubbles filled cavity opposite to the sun-facing side is able to scatter back significantly more light than would be possible with a simple transparent glazing. The use of Liquid Bubble Insulation to both insulate the north side of the VG and concentrate sunlight entering from the south side is a very appropriate adaptation for cold winters days, while it is more rarely important to optimize the use of Sola Roof technology for shading and cooling effect in the nordic regions. However, when cooling is desirable we only need to reverse the winter scheme and use bubbles in the south, sun-facing side. My activity in the tropics and sub-tropics has led me to appreciate that a completely different strategy is needed for optimum VG operation in the low to zero latitudes, which I will present in the next section.

2) tropical to sub-tropical

Life in the Tropical Climates, both the humid tropics and hot, arid sub-tropics have very different challenges than those those answered by the development of Sola Roof technology in the Nordic Climates? of Canada and Norway, where I have worked most actively developing Sola Roof. However, summer experience with the cooling of a Tunnel Greenhouse and the commercial Wide Span structures that have been built, have shown that Liquid Bubble Insulation is also very effective to isolate the growing environment from a hot external climate and Liquid Bubble Shading? will protect the plants from excessive radiant heat of the sun.

I have visited greenhouses in many tropical regions, from the hot, arid lands from Arizona, North Africa, the Middle East, Rajasthan to Almeria in Spain and also humid tropical Mexico to Malaysia where shade mats, curtains, ventilation, evaporative cooling and even air-conditioning have been used to try to prevent overheating of greenhouses. What was evident is that even in shade so deep that I feel certain that virtually no PAR was available to the plants, there was a total inability to prevent excessively high temperatures. This is the situation for all greenhouse types, including glass and plastic and no greenhouse technology is currently available that provides a low-energy solution to this very difficult technical challenge.

Using conventional glazing and shade systems results in an overheating potential is so high that the ventilation required is at a rate of one complete volume change per minute during mid-day hours. Such ventilation prevents the containment of transpired moisture or enriched CO 2 atmosphere within the conventional greenhouse in these regions. The solution to be used in the VG that will maintain a cool, closed environment in these same conditions is the application of the Sola Roof technology where both the Liquid Solar and Liquid Bubble Insulation & Liquid Bubble Shading? work in concert with a Liquid Thermal Mass system and these systems are further optimized in performance by the special geometry and layout of the tropical VG.

The principle difference of the tropical VG in comparison to the nordic design is not the shape or geometry but rather the orientation of the large sun-facing sides of the VG to the east and west (rather then north/south in the mid to high latitudes) so that the Sola Roof technology can most effectively amplify (and control) the morning and evening sunlight, while minimizing the mid-day solar intensity, while at all times providing cool diffuse daylight deep into the multi-level crop leaf canopy.

In the tropics the sun transits the sky high overhead with a super abundance of light in the mid day and less availability of light during morning and evening. Therefore the geometry and orientation of the VG in combination with the flexible and dynamic capabilities of deploying the bubbles in the east or west facing sides of the VG gives a new capability to boost the early and late day light and level (reduce) the mid-day peak of excessive light. The shape of the east (for morning) and west (for evening) faces of the VG will maximize transmittance of PAR from 0 to 60 degrees of sun angle, while from 60 through 90 degrees (east and west) the portion of reflectance from the transparent cover will maximize, thus reducing transmittance at the peak sunlight hours.

At the very lowest sun angle the sun scoop technique can be used with bubbles in the west top bubble cavity in the early morning and bubbles in the east top cavity in late evening. At higher sun angles of morning and evening the Liquid Bubbles are best deployed in the sun-facing face of the VG, while no bubbles are used in the opposite face. Therefore, bubbles are filling the east glazing during the morning so as to diffuse light and remove the IR spectrum, thus controlling the quality and intensity of the sunlight to prevent overheating and maintain maximum photosynthesis and crop growth. In a similar way sunlight control and cooling is provided through the late afternoon by bubbles in the west face of the VG. And during the mid-day hours both east and west face are filled with the dynamic Liquid Bubble Insulation, to protect from solar heat gain and to refract diffuse PAR deep into the lower levels of the VG.

The Liquid Solar process for Closed Atmosphere cooling and transfer of thermal gain to the Liquid Thermal Mass is also utilized to remove transpired moisture from the VG environment and provide a regulated relative humidity, which is optimum in relation to the controlled temperature within the growing environment. Ambient heat sinks, radiant cooling and evaporative cooling systems can be used over night if required for the reduction of the temperature of the Liquid Thermal Mass system. We seek a diurnal thermal balance that will result in a sustainable equilibrium of day-to-night temperature with low-energy inputs.

While the VG is therefore a recent strategy for adaptation of Sola Roof technology to these zero to low latitude regions, and has not been field tested in the hot/humid tropics or hot/arid lands of the sub-tropics, I recommend that trials be implemented to verify and improve upon the solution that I described herein.

DISCUSSION: The increased sunlight deep within the leaf canopy of the VG is the principle advantage, however another benefit is the vertical volume of space in which to grow the maximum plants and algae on a small footprint. The small footprint compared to the large volume and vertical height that is provided creates the opportunity for an increased plant production with additional crops grown in multi-level growing systems. The VG assures that all levels of crop production from the highest to the lowest level at the base of the VG will be receiving the maximum possible PAR for rapid development and best yield. The multiple crops increase the profitability of the capital investment and the land area that is utilized. Land and capital must be minimized and the return on these finite resources must be maximized and the VG will out preform the conventional greenhouse and far out distance the most intensive of gardening practices.

The purpose of the VG is to assure that the Family Farm, including peasant farmers of the world, will have the opportunity to use a small plot of land to produce a sustainable prosperity and lasting food/water/energy security. What previously would have been a difficult subsistence life will, with the VG, become a certain capacity for prosperous and sustainable livelihood, provided that there is a Fair Trade? for the food/feed/fiber/fuel, clean energy, pure water that is sustainably produced and credit for the additional CCR (Carbon Capture Reuse?) and social benefits that the VG will provide to the wider community and for contributing to the reduction of GHG emission and achieving global societal goals. The quality of life possible to the VG farmer is very high since the VG will integrate Sola Roof technology and Life Synthesis solutions for sustainable, low or no-cost inputs using regenerative ecological systems to power and feed the production of valuable outputs. Feed crops, including algae that are continuously harvested can support the production of high value food crops, while producing a surplus of clean energy and pure water. High value vegetable, fruit, fungus, livestock and aquaculture food crops will be produced. And the continuous re-cycling of the biomass by means of integrated Bio Digester generates Bio Gas that can be used for generating clean electrical energy power and fuels far in excess of the operational needs.

There is therefore no resource limits to constrain the adoption of the VG and in respect to water, the VG operations will conserve, clean, purify and create surpluses of water that can be contributed to local needs for people, livestock, aquaculture and alternately for ecological, soils and forest restoration programs. The high productivity is highly automated and not substantially affected by severe weather brought on by Climate Change. The global adoption of the VG with its CCR capacity will have the largest impact of any food/energy strategy for the reversal of GHG in the atmosphere and provide a serious and substantial mechanism to reverse Global Warming by rapidly reducing ppm CO 2 to below 350 as is thought to be an urgent requirement for stabilizing planetary climate and restoring the conditions for the earth to recover ecological health.

As a distributed solution to the supply of food, water and energy, the VG will empower each household to be self reliant and will substantially reduce the transport of these consumables over long distance. Localization of production and regeneration locally of consumables will greatly reduce energy expenditure and CO 2, with not only the elimination of energy consumption for transportation of fuel and foods but also connected with food refrigeration and processing, since more food will be consumed fresh. The bulk of the food supply can become local and fresh which will greatly aid nutrition and health. The pace of urbanization could slow or even reverse, while the quality of life in "the country" can become very attractive. Due to automation the VG farmer will have the majority of his/her time free for investment in other purposes and communities will therefore have a rich human resource available from members who can gift, barter or exchange their time for local goods, services and recreation/art/entertainment in a local cultural forum/exchange. These are a great ways to live a good life that will not cost the planet or the next generation. The economic system will need to evolve to create Fair Trade? and exchange among people who live with abundance of all necessities and where commodities are not priced by scarcity. The VG for self-reliant living cannot by itself transform the systems of finance, but it will have an impact and lead to paradigm shift across many sectors. This is a deeper transformation that will emerge out of such a powerful demonstration that working with nature and deploying Biomimicry Technology and Ecomimicry Architecture will have the effect of removing most fears people have about forecasted rapid population and prosperity growth. This is an indication that Eco Habitat/Green Growth is possible and the VG is a mechanism for sustainable growth and prosperity that results in no threat to the environment.

The ideal financial model for a vast deployment of the VG is micro-finance, where the capital cost of a VG is supported by a social/ethical investor (as contrasted to lenders who fund through debt creation) and global to local communities of VG farmers will cooperate (see: Sola Roof Coop) in support of their individual and collective well being and financial success.


In relation to the Vertical Greenhouse, I would like to make a connection with Dr. Dickson Despommier and his book "The Vertical Farm" (Oct 2010), which I have recently completed reading. On my first look at this book I had some difficulty with it's optimistic view, which seemed to gloss over existing constraints faced by "flat land farming" including the best greenhouse growers - who's industry is failing to cope with these realities. Also, going vertical will not increase the availability/utilization of sunlight above what is now accomplished by high-tech, flat-land farming with the best of Controlled Environment growing. The reality not discussed is that this controlled environment growing is highly dependent on intensive energy consumption and is also making an extremely high contribution to water depletion and to GHG emission and therefore to Global Warming. A recent study published in Norwegian shows that local growing in greenhouse Vs the trucking in of the same produce from distant field growers, the unexpected result that the food miles alternative has far less CO 2 footprint than the best and most efficient of greenhouse production.

Vertical growing will result in shading of crops by leaf canopies above and by the structure itself - and the problem with this is that food crops need maximum light to grow to harvest weight, which is why multi-level crops are not the rule in the greenhouse industry. Thousands of advanced growers would love to multiply their output if this would work, so we should accept the inconvenient truth that Despommier and others are establishing an unrealistic hope, based on a perfectly understandable wish to find a way to feed "the one billion people...hungry...and the three billion more...who will most likely join them...if nothing changes", as he states in the dedication of the book.

To a limited extent multi-level growing is practiced and supplemental lighting has also proven to increase yield and profit, but commercially successful growing under artificial lighting has proven to be a non-starter. Despommier refers to NASA and makes allusions to high-tech factory farming, but fails to mention of the multi-millions invested in such research by General Electric in their Genoponics venture, or the experience by Kraft Foods and others who, in the 70s made the most determined effort to establish vertical factory farms in hydroponic warehouses, with total environmental control, enriched atmosphere CO 2 and lamps and who failed completely with these efforts. The idea that there are now lamps that produce more specifically the PAR (Photosynthetic Active Radiation?) spectrum is presented as a possible breakthrough but without acknowledging that plants respond and require sunlight outside of the PAR spectrum for flowering and pollination and other factors that are complex to the extent that it is known that growth chambers are limited in their capacity as a research tool since they do not replicate the natural environment or natural sunlight, from which plants take important queues for their morphological development.

Even with the best of lamps we do not do better than with natural sunlight, which is free. So, in reality flat land farmers will always have a great advantage of maximum free sunlight. To use electricity, which is our most expensive and CO 2 costly energy, to replace the ideal and free sunlight in a world struggling for new energy paradigms is an unlikely direction. Rather than a future senerio where food becomes dependent on our ever more expensive high-grade energy production, it is much more likely that the wise application of photosynthesis will be a source of clean energy that we can apply to other societal needs - plants can produce the food we need and in the process form biomass that we can use for producing clean electrical power. The billion people who are hungry also need lighting and other essentials provided by electrification that people of the west take for granted; electrical lighting for plants (other than supplemental lighting) has a huge carbon footprint; it is based on a false and unsupported assumptions.

So, we need to set aside the mis-information that Controlled Environment growing, as it is practiced today is low-energy or low-carbon as compared to outdoor flat land growers. And abandon the sci-fi images of crops growing under lamps (no matter how efficient) and then think in a practical manner about the solutions that would still enable the benefits of nature within our cities or "built environment". Getting close to nature and learning to use the regenerative energy, nutrient and water capacity of an ecological system is very much the right direction for solution of the biggest challenges facing humanity. I do agree with Despommier, that such systems integration will create a new paradigm, Ecomimicry Architecture - which is an idea that is bubbling up between myself, Ken Yeang and John Todd - Yeang says , "Our built environment must imitate ecosystems in all respects. and Todd"s work shows human empathy and understanding of the complexity and diversity of these organic systems to a degree that enables the engineering of ecological processes into our habitat, creating an ecomismesis.

Since modern architecture and engineering can offer us the option of making the neglected roofscape of our cities into a new home for the Vertical Farming, what reason is there not to welcome the Farmer into the City where we can benefit from this integration and close proximity to food production. Here is where I then add a dose of pragmatism. I do not anticipate any magical result that will multiply this roof level plant (and probably algae) production into a multi-floor operation. The highest crop growth will be possible only in the top level of the buildings and sunlight that is not thus utilized fully for photosynthesis will be needed in the cityscape below for daylight, with buildings designed to diffuse light deep into the lower floor levels, where greenery is for beauty and esthetics.

Having made this point, I would anticipate that the great creativity of the citizens who will participate in the creation of Ecomimicry Architecture will result in a significant further percentage of food production with multi-floor level plant production, using lamps for supplemental light. Shade plants and vegetative (leafy) plants can be grown away from the maximum light at the roof level.

It is important to note that living plants do much more than produce fruit that we can harvest. They produce oxygen and fixate CO 2 in their biomass, which means that they are constantly concentrating CO 2 from the atmosphere. And once captured and concentrated as carbohydrates we can then avoid the release of this carbon back into the earth's atmosphere. When we transform the waste biomass with Anaerobic Bacteria using Bio Digester technology, which transforms the captured carbon (in carbohydrates) into CH 4? (methane) and CO 2 (Carbon Dioxide) in the gaseous product, which we call Bio Gas. The Bio Gas is combusted for clean electrical energy and the CO 2 produced is not released to the atmosphere but is contained within the Closed Atmosphere plant and algae production areas. Elevated CO 2 and maximum light produce maximum photosynthesis and plant growth. The time to harvest is reduced and the crop yield increases in weight and quality.

Light and CO 2 balance should be optimized and spread out into multi-levels to result in best production of food, feed, fiber and fuel products for local consumption. Additionally, the Vertical Farm? take advantage of opportunities to produce aquaculture crops and livestock at lower levels, being aware that all creatures require some degree of natural light for health and wellbeing. The question that needs to be answered is - to what extent is it possible to use vertical height of a building to increase the biological output if it is designed to be an optimum ecomismesis.

The first thing to acknowledge is that the vertical building will have more light incident on its building envelope that is possible for a building of the same footprint that is relatively flat in comparison.

Why will the vertical building have a light advantage? The answer is that the vertical building benefits from "seeing more" of the solar angle of sunlight as the sun arcs through the sky each day. The flat building will gain light through the roof but the vertical building will additionally gain light through the wall area, which will typically be large comparative to the roof area - that is a benefit of "going vertical". The off-setting issue is that this building casts a solar shadow; so, the vertical building gains light at the expense of the neighbor, who's interests must be considered (called solar rights).

Greenhouses with a southern exposure have been built with a view to gaining greater winter light by means of a vertical construction but results have shown that substantial shading for periods of the day or whole seasons (due to sun-angle) is often quite detrimental to good yield of food crops. Therefore, a west, south or east wall at times of the day or during seasons will receive little natural sunlight and sky radiation and/or supplemental artificial light may not result in a good harvest comparative to the crop under a horizontal glazing. Without experimentation there will not be answers to the question of the possible benefit of crops grown at the walls. The potential of growing to the interior space near the glazing curtain-walls of tall structures is certainly limited and I re-state the not so obvious issue that lamp light will result in food with the highest carbon footprint, which brings a conclusion that roof level areas with good sunlight are best for plant and algae photosynthesis.

However, plants at walls or within the lower floor area of a vertical Ecomimicry Architecture can have many benefits other than for food harvest. Living plants process water and humidify their environment. They remove CO 2 and clean other VO Cs? from the air, while emitting other VO Cs? which may be found to be beneficial. Plants also sustain ecological systems, within the leaf and root environment. The root environment provides symbiotic biota a "home" and the ecology of this root zone (in aquatic media or soil) is a living system with organisms that can have tremendous value when we appreciate their function and natural capacity to metabolize pollutants in the air or water. The Living Machine?, by John Todd is an example of such cultivation of specialized ecological systems that are maintained in the root zone of aquatic plants - the goal is not to harvest these plants, but to let them host the complex matrix of bacteria (that do not need sunlight) and since there is not a rapid plant biomass growth, there is not a need for bright daylight. These ecological systems can be located at the lower levels of Vertical Farming. So can the Bio Digester systems, aquaculture and mushroom production. And under the surface of aquatic systems and within the soils there can be produced (at the lowest levels of Vertical Farming) worms, algae blooms, fermentation tanks and space for the creation of organic soils and soil conditioning products. These are the products of fully treated organic solids that will be continuously produced in excess to the needs of the continuing operations of Vertical Farming.

The Big Problem!

Now to face the principle challenge remaining unasked in Despommier's Vertical Faming? idea, all current greenhouse technology is horrendously costly financially and environmentally. That Vertical Farming can be proposed as a the solution for the hungry (and the rest of us also) to live a good life without coming to terms with the technology issues that are confounding the development of controlled environment greenhouse is to make Vertical Farming into a pipe dream. Modern plastics industry have given us options for very cheap covers for greenhouse structures, but Vertical Farming brings the greenhouse into an urban built environment, which must meet safety codes. But the biggest problem is not the capital investment needed for building a greenhouse but rather it is the operating cost (and to run the greenhouse that is the problem.

When energy used to be cheap and there was no concern about carbon footprint there was opportunity in "out of season" crops that are picked vine ripe - and distributed locally for the high-end of the fresh food market. But since we entered the era of OPEC and now have the certain prospect of Peak Oil as a backdrop to the serious concern of Global Warming - we can expect to see high energy costs continue to trend upwards to a point that greenhouse producers will not survive.

In these difficult times we need to be clear about the constraints and not chase dreams that have no foundation. In my discussion above I have tried to make it clear that when it comes to feeding the world, we must look to the roof level of Vertical Farming for the sunlight to produce the food, which resource has definite limits that cannot be overcome by use of artificial light or some similar technology "quick fix" because electricity has the highest carbon cost of all energy, while plants are designed by nature as carbon negative when running on sunlight.

I would also like to see some clear thinking about the idea that a greenhouse on the roof of our homes and buildings is the same as "free energy" since we do not then heat and cool our homes and buildings. If this idea was adopted to provide habitat + food to the world's population then buildings would go from their current 50% contribution to Global Warming to become the leading cause of what Despommier has called Rapid Climate Change? (RCC).

The hard reality is that to make Vertical Farming a positive contributor to the avoidance of RCC and to operate sustainably and produce affordable food in Controlled Environment systems as energy cost escalates due to Peak Oil we need a breakthrough in greenhouse technology that reduces the heating and cooling cost associated with a transparent building by a factor of 10 times or more.

The Sola Roof technology BREAKTHROUGH!

An unexpected answer is now on the horizon that will enable the vision of Vertical Farming to be realized very soon and this technical solution to the heating/cooling problems of transparent building envelopes is Sola Roof technology. I can understand that something so simple and freely accessible as Liquid Bubble Insulation could remain invisible to the building sector and the scientists and technologists who search for answers to the present energy inefficient glazing systems.

The difficulty is that additional layers of glazing, which increase the thermal resistance, will also decrease the light transmission and increase the cost - so, we have been effectively at a standstill with any improvements in efficiency coming at a very high cost. Food produced under glazing must be affordable, which for practical purpose means that the glazing system must be cheap to build and cheap to operate. For higher northern latitudes, where reduction winter heating costs are key to "out of season" growing the only notable advancement over the last 50 years is the American "pillow roof" innovation using a double film cover with stabilizing air-pressure system.

In the low latitudes where summer cooling is the key to out-of-season growing, the inadequate technology offered to the industry are shade curtains that are used together with natural or mechanical ventilation. Temperature and Humidity in the most high-tech commercial greenhouses remain "out of control" and are managed by energy intensive mechanical systems in those projects that claim in some degree to provide Controlled Environment growing. A handful of exotic and super costly projects have explored the potential of Closed Atmosphere growing at full sunlight, including NASA's CELSS Program, Biosphere II in Arizona, Innogrow in Holland (using ground water heat pumps) and in a few Biotech research labs/growth chambers using air-conditioning equipment.

The NASA program managers included key personal with experience from the GE Genoponics developments. CELSS (Closed Ecological Life Support Systems) is not only about Closed Atmosphere, which therefore contains and regenerates CO 2 and humidity (transpiration of plants) back to hydrocarbon and water, but which also regenerates the nitrogen and minerals using integrated Bio Digester systems to power Combined Heat Power? (CHP) technology. All of these closed systems are provided by our current Life Synthesis project which is enabled by the energy efficiency of the Sola Roof technology.

Comparative to the NASA research and development, the Sola Roof technology is decidedly low-tech and low-cost and our Open Source method for Controlled Environment is actually Closed Atmosphere and therefore provides considerable advantage over the current state of art greenhouses, which are all ventilated. Sola Roof uses the Liquid Solar technology for temperature and humidity control and Liquid Bubble Insulation for cold winter nights and Liquid Bubble Shading? for hot summer days and for energy efficient cooling in hot climates.

The expectation that Sola Roof technology presents a breakthrough for the Vertical Farming proposal is very high and as a step forward with a proof of concept project I have proposed the Vertical Greenhouse as a test of the possible benefits of going vertical by offering proof that an unusually vertical greenhouse will show significant benefits in comparison with a normal low profile greenhouse. The Vertical Greenhouse will pioneer solutions for Vertical Farming by working out problems and exploring the creative advantages of a smaller footprint and more intensive production for the Family Farm, including low-cost solutions for raising the subsistence farmers of the world to a new level of comfort and prosperity.

In this new paradigm of living closely with nature - in fact, inviting nature into our homes, communities and work spaces - there is certainly a value to thinking in 3 dimensions - to acknowledge the importance of a vertical component in our built environment - and it this respect Vertical Farming integrated with cities can establish a fundamental advantage over a Flat Land Farming approach in which farming is zoned outside the city. That said my objection to the general portrayal of Vertical Farming is more concerned with addressing the constraints of a viable Vertical Farming and is perhaps less optimistic about Vertical Farming producing a "super abundance" through some technological brilliance. I am convinced that "Flat Land Farming" using the modern Controlled Environment greenhouse is already touching on the maximum possible yield that our human interventions can produce.

Secondly, I caution that all the book, The Vertical Farm wrongly presents current Controlled Environment greenhouse technology as low-carbon but in truth it has the highest of carbon footprints, water consumption and energy consumption - to the degree that the future of the industry is threatened. Yet, in Vertical Farming, Despommier presents the greenhouse sector to the reader with an aura of being, with the technologies of hydroponics and controlled environment growing, the perfect solution to the global crisis of food, water and energy scarcity. This it certainly is not!

Vertical Farming seems to recommend creation of a vast area of transparent building envelope - and with current poor energy performance of glazing systems this will neither help to produce affordable food for billions, nor would this reduce humanity's carbon footprint. However, since Sola Roof provides a solution for the limitations of glazing systems, as further explained at this Wiki, I can go along with Vertical Farming and take a practical look at the advantages that could benefit people and planet.