Category Archives: agriculture

Garden cities and forest gardens

In Ebenezer Howard’s Garden Cities of Tomorrow (1902), we can read his proposal to surround a 1,000-acre town of 30,000 residents with 5,000 acres of farm land. Since in space industry and agriculture will mainly be located outside space settlements, we could look for alternative uses for this land.

Howard pays little attention to recreation in his book. Though his design includes a central park, his garden city plan does not reserve land for sports such as field hockey and ultimate. Because sport does positively affect human wellbeing, we propose to reserve some of the land originally reserved for farms to sport fields.

In chapter 10 of his book The High Frontier (1976) O’Neill suggests that space settlements are ideal locations for gardening. Our suggestion would to combine “O’Neill” and “Howard” by reserving a substantial portion of the “farm” land for allotment gardens. These are gardens assigned for individual, non-commercial gardening.

O’Neill also advocate the concept of polyculture in his book. Polyculture is the practice of growing of multiple types of crop in the same plot of land. It’s the opposite of monoculture, which dominates modern agriculture. Scientific studies have shown that polyculture is preferable to monoculture.

There are several types of polyculture, one particular interesting concept are forest gardens. The practice of forest gardening is an ancient one, but Robert Hart has formalized it in his seven-layer outline. The first layer consists of mature fruit and nut trees, which (of course) will provide fruit and nuts. The second layer consists of smaller trees, while the third layer contains fruit bushes (currants and berries). Then the fourth layer are perennial vegetables and herbs. The fifth layer are root vegetables, the sixth are edible plants which grow horizontally. The final layer consists of vines and climbing plants.

Forest gardens is considered as a low maintenance type of gardening, and hence suitable for allotment gardens. Most people with allotment gardens, work there in their spare time. An additional benefit is that forest gardens contribute to food security by providing a wide variety of food. Potentially forest gardens could be established on rooftops.

Forest gardening is a type of agroforesty, the combination of agriculture and forestry in one system. Agroforestry does not need to limited to non-commercial allotment gardens, the utilization of non-timber forest products in forest farms can make forests management commercially interesting. We propose that forest farms should be leased to private parties, on the condition that these forests will be open to the public (see also our post on Allemansrätten).

Timber and paper in space settlements

The inhabitants of space settlements need to establish their own supply of wood, both as timber as for the production of paper. Importation of wood from Earth will be a costly affair, and unfortunately it takes several decades for trees to grow to commercial height. Alternative sources for tree wood have to be found.

We can use hemp as a resource for production of paper. One advantage of hemp is that it is a fast growing crop. Further hemp has a lower lignin content than wood. Lignin is an unwanted substance in paper, and hence has to be removed from pulp. A serious challenge is that hemp has a low cellulose content (relative to wood), however, through genetic engineering the cellulose content of hemp might be increased.

Another application of hemp is the production of fiber boards. Fiber boards can also be made of bamboo, a fast and high growing grass. Certain types of bamboo, known as timber bamboo, can be used as timber either directly or as resource for engineered wood.

Another alternative for tree wood is rattan, also a fast growing plant. Furniture and baskets made of rattan are well-known, and there is no reason why space settlers will like them less than terrestrials.

Roof gardens and efficient land use

A standard O’Neill cylinder provides about 321.6 square kilometers of usable land. For comparison the surface area of Singapore is 716.1 square kilometers. Since a standard O’Neill cylinder contains only a small amount of land, efficient land use will be essential. (Larger cylinders can be built, but they are unlikely in the early stages of space colonization.) Continue reading Roof gardens and efficient land use

Time zones and separation of functions

One of the major advantages of space colonization by the use of free space habitats instead of planetary “space” colonies, is the separation of functions. Gerard O’Neill already advocated that residence, agriculture and heavy industry should be separated from each other, i.e. that agriculture and heavy industry should not be done in the same structure where most residences are located.

In regard of the separation of agriculture and residency, O’Neill gives two main arguments. First, in a space settlement we have full control over both climate and day length. However, the climate preferred by most citizens is not necessarily the most optimal climate for the cultivation of crops. Second reason is pest control. If in an isolated space farm a pest will occur, it will be easy to deal with it by sterilizing the farm by increasing temperature above the limit life cannot survive. It’s quite obvious that we cannot do this, in a space habitat populated by humans.

For the separation of heavy industry and residency, the arguments are even more straightforward. Heavy industry impose a great danger to health and safety through its pollution and potential of explosion and similar disasters. By banning heavy industries from space habitats, we create a clean and save environment for people to live.

A second argument put forward by O’Neill is related to his proposal to divide space settlements over three time zones, with a 8-hour difference between each successive zone. Because heavy industry is located outside any space habitat, they can be in continuous operation. And if the industry hires shifts from different time zones, night work which is considered as unpleasant by most, will be avoided.

O’Neill imagined that space settlers employed in heavy industry, would commute each day between their home and their workplace. But technology has improved much since the mid 1970s, that nowadays much work can be automated and where people are still needed teleoperation will allow workers to run factories without leaving their space habitats or even their homes.

Besides the desire the avoid night work, there’s another reason for dividing space settlements among different time zones (which surprisingly is not mentioned by O’Neill). The principal power source of space settlements will be solar power. And since there’s no night in space (in space settlements night has to be created by covering the windows), space based solar power plants will run continuously and hence have a continuous output. But the demand for power is not continuous over the day, causing surpluses at some moments and shortages at others.

If we divide the population of three time zones with an 8-hour difference, the power demand curve will be flattened. This because if one settlement is facing a power shortage at some point, it’s likely that another settlement has a surplus since their population is experiencing another phase of the day.

Space colonization and genetic engineering

Although Space colonization and genetic engineering are separate concepts and the creation of space habitats is perfectly possible without the use genetic engineering, we believe that genetic engineering is a key technology for the success of Space colonization. Continue reading Space colonization and genetic engineering

Space colonization and vegetarianism

In a previous post we critically reviewed Elon Musk’s Mars colony plans and we mostly destroyed his idea. However, there is one good aspect to Musk’s plan. According to this article, Musk’s colony would be an all-vegetarian society. The question is, of course, why does Elon Musk want a vegetarians-only? [For the purpose of this post we will consider vegans as a subcategory of vegetarians.] Continue reading Space colonization and vegetarianism

Vertical farming?


World population is expected to grow to nine to ten billion people around 2050. And all this people need to be fed, but arable land scarce. Most land suitable land is already in use, so the challenge is obvious. One of the proposed solutions is urban vertical farming, i.e. growing crops in skyscrapers. In this post I will question whether vertical farming is actually a good idea.


The Wikipedia article on vertical farming mention several advantages of this mode of agriculture. First there is the preparation for the future argument: since there will be more people, we will need more land for agriculture and one way to do this by stacking up several layers of greenhouses. The second argument is about increased production, since indoor conditions are controlled we can produce crops all year round. Which means a multiplication of productivity with several factors. Related to this argument is the fact that indoor farming in a skyscraper will eliminate most weather related problems. Ordinary greenhouses, however do this already.

The subsequent argument mentioned is about conservation of resources, which means that by switching to vertical farming large pieces of land can be “recovered” and brought back to a more “natural” state. Also deforestation and desertification will be halted, and the need for fossil fuel powered plowing, planting and harvesting will be reduced, saving fossil fuels and reducing carbon dioxide emissions.

The next argument goes that by indoor agriculture less pesticides and the like are needed, therefore food will be healthier. The last argument I want to mention is the energy argument. The proponents argue that by employing methane digesters the farm will be able to produce some of its own power needs.


Well, its true that by using  organic waste as an energy source, some reductions in external power supplies can be made. But I do not think that will be quite significant. From the second law of thermal dynamics we know that in a closed system the total energy is constant, it can only change from one form to another. If we subsequently extract energy from such system, the amount of contained energy in the system is lowered. What crops do is, energetically speaking, converting solar energy into chemical energy (stored in sugars and starch). Should we initially consider a vertical farm as a closed system, if we then remove some crops (for sale) and the farm will lose energy, which should be replenished. With only biogas from organic waste from the farm, we will still lose energy. What we need is an external supply of energy.

Since vertical farms will put layers of crops atop of each other, they have to replace sunlight with artificial light. Some research shows that with proper lighting will increase production in comparison with sunlight (this is due to the fact that plants will only absorb light of certain frequencies, and all other frequencies [notably green] will be reflected). And this lights have to be powered. A lot of energy is required, for heating the building, air circulation, pumping water and lights. Actually there is only one energy source suitable for powering vertical farms, and it is not solar, bio or wind power. The answer is probably not the one which is favoured by vertical farm proponents. Only nuclear power plants are able to provide a stable and reliable power supply for vertical argrarians.

Since the members of the Vertical Farm movement are eager to point out how environment friendly their ideas are, it is quite remarkable to see that they do not tell how they want to power their plans. They only mention energy recovery through bio methane gas and saving energy by reducing transportation. But this is not enough, we need a good plan about how to power such structures and how to finance it. History provides ample examples of nice plans, but which failed because the were not properly explained (the notorious Freedom ship is a classic).


The need for feeding nine billions people is out of the question, everyone acknowledges this. The actual question is how to do this. Vertical farms are one solution, but what are the alternatives? My favorite is the saltwater greenhouse. This concepts relies on the Sun to evaporate seawater, which is thereafter liquefied and used for the crops, but for more details you should check this link.

The most suitable places for saltwater greenhouses are large pieces of desert. The Sahara is on the first place of candidate locations. The world’s largest desert is sparsely populated and receives more solar energy than any other place on this planet. Further its location is strategic. Only a modestly small proportion of the Sahara is needed to generate enough energy for the entire world. What I mean to say is that unlike the vertical farm concept this plan is much more realistic, it is clear how it is powered. And unlike vertical farms, it can be done at small-scale, after which it can be scaled up. Therefore it is possible to test in practice before investing large sums of money into the project.

What about the energy cost of transporting food from the Sahara the rest of the world? Well, energy enough in Northern Africa, I would say. Just converting solar energy into some fuel. There are a number of methods to produce so-called synthetic fuels. Actually there are plans to build large solar farms in North Africa which should be linked to the European Superlink.

But there are other solutions for solving the global food shortage. First we should note that a lot of the world agricultural production are crops for feeding livestock, by consuming less or no meat we need less land to feed the world population. Secondly we have to understand that the food problem is actually more about distribution rather than production, in fact the total world food production is enough to feed everyone. But since there is unequal distribution of wealth in the world, some people do not get what they need. Perhaps we should solve this problem politically rather than technologically.

Vertical Farming in space

This post, however, is about vertical farming on Earth. But this concept might have more potential for space colonization, I will work this out in an upcoming post on this blog.


Space colonization and invitro meat

This post was originally posted on on January 19, 2012

Even since the time of Gerard K. O’Neill space colonist advocates are concerned on the issue of producing of meat in future space colonies. One of the main concerns is the conversion rate of meat. This means the amount of food which is needed to feed livestock to produce an amount of meat, e.g. the conversion rate for cattle is 10:1, which means 10 kg of food is needed to produce 1 kg of beef.

Anyone would know that agricultural space is a precious commodity in space settlements, especially in the early years. So it’s unlikely that in the first years of space colonization there will be a native meat industry. But the cost of importation of meat, even without any kind of tariffs, will be prohibitive high. And due to our preferred location in the Sun-Earth’s L4/L5 points, it will take months before a cargo meat will arrive from Earth to our colonies.

A possible solution for this problem are the use of plant protein based meat analogues. In recent years meat analogues are rather good in mimicking real meat products, so good that is sometimes hard to distinguish from real meat. Another solution is in vitro meat, in this process animal tissue is cultured in the lab. The main advantage of this is that it is a lot easier to transported (deep frozen) samples of tissue of several kinds of animals to distant space colonies than entire herds of animals.

Another advantage of in vitro meat is that it offers the possibility of a broad range of kinds of meat to choose from. Furthermore the technology used can also be applied for medical purposes. Therefore we can conclude that in vitro meat is a valuable technology to be developed by Space colonists.

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