In a water-world where the only "land" are the floating, rotting corpses of titans, how would a medieval civilization develop agriculture?

Since they are of medieval technology level, hydroponics seems like an unlikely solution. This water-world also has a range of seabed depths, meaning there are places with reefs and kelp forests--however, solutions that accommodate agriculture on the titans is preferred. Fungi are also an option, though not preferred as they risk decomposing the titan.

How could sufficiently sustainable and productive agriculture be developed to support this soil-less society?

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    $\begingroup$ Have you considered aquaculture? Fish farming? Mollusc farming? You might also want to describe the "land" a bit. What's it made up of? Apart from the "rotting corpses of titans"? Also, are there even plants on this world? $\endgroup$
    – elemtilas
    Jan 28 at 4:09
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    $\begingroup$ These rotting titans, if they're "rotting" that implies decomposition of the sort we're familiar with, so why haven't they sunk? the corpses we're familiar with only float for any length of time because of gasses from decomposition trapped inside the body but it rarely takes long for the decomposition to advance to the point where the body and it's tissues no longer have sufficient integrity to hold gas inside them and they sink, so why haven't they sunk yet, and how is there anything but bones left in a civilisation spanning time-frame if they are decomposing? $\endgroup$
    – Pelinore
    Jan 28 at 14:04
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    $\begingroup$ Also, why isn't there soil? .. if they're decomposing then sooner or later there's going to be soil (or at least a growing medium of a usable sort) for plants .. and if they're not decomposing and are large enough bird guano, and other material deposited on them will produce a layer of soil on top of them the same as it does on any newly formed barren volcanic island over time, a process that can be easily accelerated by people if they want by dumping seaweed and dead fish on them .. so why do you have a soil problem? $\endgroup$
    – Pelinore
    Jan 28 at 15:18
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    $\begingroup$ Agriculture was not developed in medieval times. In our world, agriculture was developed in the fertile crescent as it dried out and later moved into Europe as the next generation of farmers saw some empty land and left their parents to start their own farms. Agriculture was in Europe thousands of years before the medieval time. $\endgroup$
    – David R
    Jan 28 at 15:45
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    $\begingroup$ Better question what source of terrestrial crops do they have? if plants grow on the corpse use them, if not there is nothing to use in the first place. $\endgroup$
    – John
    Jan 29 at 1:28

6 Answers 6


Recent studies have found that, very likely, water worlds are not so life friendly due to the severe limitation imposed on the phosphorus cycle by the lack of dry land.

Considering that phosphorus is a key element for plants, which are then the foundation of the food chain, it's easy to understand why.

That said, even assuming that life found a way to be without phosphorus, I highly doubt that a civilization would reach medieval level without having developed agriculture way before their time.

Without agriculture there are only hunter gatherers.

  • $\begingroup$ "Without agriculture there are only hunter gatherers." Or fishers. $\endgroup$
    – user108065
    Jan 29 at 11:35
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    $\begingroup$ @Ben what are fishers if not hunters? $\endgroup$
    – L.Dutch
    Jan 29 at 11:35
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    $\begingroup$ Indeed. I just wanted to point this out. Not everyone thinks of fishing when they read "hunt" and "gather". Our mental image of prehistoric tribes is often of people on dry land. Also, there are scholars (e.g. Hans-Peter Müller) who distinguish fishers from hunter-gatherers. After your long explanation why life isn't possible on a water world, I just wanted to make sure people don't read your last sentence as: "Without agriculture, there are only hunter-gatherers, and since there is no land to hunt and gather on, on an ocean world, human subsistence is impossible there, too." $\endgroup$
    – user108065
    Jan 29 at 11:54
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    $\begingroup$ @L.Dutch there is a huge difference because (sea) fishing is closer to agricultural society than to hunting one, in that you do not need to move to follow herds or can meaningfully deplete the livestock you are taking from $\endgroup$
    – Hobbamok
    Jan 29 at 16:50
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    $\begingroup$ @Hobbamok Nomadism is definitely correlated with hunter-gatherer technology, but there exist (or have existed) hunter-gatherer societies which are relatively sedentary. The standard anthro 101 example is the peoples of the American northwest, e.g. those people who were indigenous to coastal Oregon, Washington, and BC. These people are generally considered to have a hunger-gatherer economy, but in an area which is resource rich, and supportive of a sedentary lifestyle. But these classifications are all quite fluid--- $\endgroup$ Jan 29 at 21:11

First, if there never was any dry land and this world was not a freak product of a powerful superintelligence, it won't gonna happen. No plant species suitable to live in dry land would ever evolve, so there would be no way to create them on floating corpses. Further, humanoid species are suitable for living on land, and without it, they wouldn't ever evolve and hence whatever is the definition of medieval for that civilization would then be completelly different than what it is in our world. So I'm considering this scenario as out of the scope.

This leaves us with two options: Either the planet was enginnered like this by some superpower or the inhabitants are the survivors of some cataclism that sunk all the dry land. Both ways are achievable if the planet was either conceived or previously inhabited by those powerful almighty titans that went warring against each other to the point that they eventually destroyed all dry land and killed themselves. Or perhaps a natural cataclism like a watery comet impact did that. Anyway, the survivors likely live in small boats or rafts with some few precious seeds to plant somewhere.

Further, there are aquatic plants, algaes and kelps that could be harvested from the oceans. But this is gathering, not agriculture, however they could be used as a starting point. Also, people could grab sand from seabed, mix it with poo and/or with dead sea animals parts and you have some sort of soil. To prevent that, you will need to make it impossible or unpractical to get enough quantity of sand from seabed.

You didn't say what is the composition of rotting dead titan flesh. If it is similar to rotting dead human flesh, this won't gonna happen, their carcasses would decompose in a few months at most liberating whatever gases and fats that make them float and then they will sink. If there are scavenging fishes, crabs, barnacles, fungi and bacteria in the water, this would happen faster. So, their flesh must at minimum contain some sort of chemical that hinders decomposition and repels scavengers.

Anyway, let's suppose that the dead titans are just free-floating boats that you don't want to damage. Also, either there should be thousands of them around or if they are few, they should be really huge, having several kilometers in height. Otherwise, they would be too few to support anything that could be called as a civilization, medieval or anything other.

Now, if they are just very large boats, let's see how you would support soilless agriculture on a small boat and then just make it larger:

  • Option 1, as you suggested, is hydroponics. But aside from a few salt-tolerant species, people would need a complex set of bottles and pipes to vaporize the water and recollect it in order to remove the salt.

  • Option 2 would be planting in vases using cotton or paper as a substitute for soil.

  • Option 3 would be to plant salt and sand tolerant grasses that sometimes grows on beaches.

  • Option 4 would be to use rootless mosses.

  • Option 5 would be to use aquaculture.

Further, poo and/or dead animals remains can be used as a fertilizer.

However, any of those options tends to fail hard for a simple reason: Severe lack of raw building materials. Our medieval civilization was heavily reliant on wood. Metal, ceramics, glass and stone bricks were also important. But in this world, there is no wood to be extracted from forests nor to be burned for heat. Without anything to burn for heat, no ceramics nor metals nor glass could be produced even if you could somehow get the correct type of soils for those from seabed, which, you can't since those were already ruled out. Coal is also ruled out, since it is usable for making fertile soil (and when was the last time you heard about seabed coal mining?). Stone could be gathered from the ocean bottom somehow, but since they are heavy, having a lot of them on floating boats is a bad idea. Further, it don't make much sense that you can collect stones but not sand from the seabed. Using bones, spines, scales, carapaces or flesh from fishes, starfishes, crabs, turtles, jellyfishes, corals or any aquatic animals as building materials is also a no go, since those are very poor materials for building stuff. Without raw building materials, there is no medieval age, and in fact, not even stone age. This leaves only two possible building materials: titans' rotting dead flesh and sea plants.

Using the titans as building materials instead of building platforms require destroying their bodies. But not all the bodies. So people should get some titan body and retrieve materials from it that somehow can produce whatever is needed to viabilize options 1 to 5. Option 5 is the most interesting as some kelp could be used to produce ropes and you could use those ropes to produce a kelp farm tied to a titan body, but this is also doable to Option 1. However, Option 5 is not exactly agriculture on the body, it is instead aquaculture around the body. Option 2 is possible if the titans have clothes and they have cotton-like or paper-like materials. Options 3 and 4 would require only a few raw materials to keep your plants in place as they grow on top of the titans.

  • $\begingroup$ @Pelinore Edited. $\endgroup$ Jan 28 at 23:28
  • $\begingroup$ Floating corpses would be an insanely good bed for funghi and the likes though $\endgroup$
    – Hobbamok
    Jan 29 at 16:51
  • $\begingroup$ @Pelinore There was no need to delete your comments. They were good. $\endgroup$ Jan 29 at 22:02

You can't "jump in" at medieval times, history doesn't work like that.

You need to ask if neolithic humans could emerge, then advance to bronze- and iron-age humans, if something like the ancient world could arise out of that, and so on.

And you see the problem already: Bronze and iron don't grow on trees (neither do copper, tin, etc.) and without those and metal tools, the entire evolution of civilization would stop there.

If your Titans are made of metal, you need to explain why their corpses float.

The second thing you need is competition and trade. A lot of progress happens because of both of these. It is not an accident that civilization appeared in what's today the Middle East and then spread to Europe and to India and China. All of these regions have the right combination of land and sea/rivers to facilitate competition and trade. Expansion is possible but limited, sea travel and exploration is available, the climate rewards technological progress.

If you want to have it even remotely realistic, you need to somehow replicate these factors.


Grow on the titans

While naturally occurring soil is typically a mixture of organic and inorganic compounds, not all plants require any inorganic compounds to grow. Many plants, especially the kinds the people like to eat, can be grown purly in compost made from the decomposed remains of other organisms. Moreover, not all plants like to grow in compost that has reached the same level of decomposition. Squash, Melons, and Potatoes for example all grow well in unfinished compost meaning that the living things are still in the process of actively decomposing. So, growing directly on the partially decomposed flesh of the titans is perfectly plausible.

Furthermore, if your setting involves any plants evolved to grow above the water on this planet at all, it would be almost certain that thier biology would favor the flesh of titans as thier growing medium. So, don't believe that just because it's not the favored medium of life on earth that it would not be the favored medium on another planet where it is the only option.

Not only would the dead bodies provided the needed nutrients, but the root structures of agriculture will help hold the body together as natural decomposition starts to break it down; so, agriculture will actually improve how long these temporary "land masses" will last making it a win win.

As a side note: I've actually grown potatoes in both soil and compost before and the ones grown in pure compost can be planted much closer together without competing for limited micro-neutrants; so, I got about 7 times more yield per square foot. So not only would your titans make agriculture possible, but they would increase what density you could grow your crops; so, instead of needing a 2-5 acre farm per family, you could conceivably support an entire family off of the back of a 0.25-0.75 acre titan.

  • $\begingroup$ Minor correction: soil is a mixture of decomposed organisms and inorganic materials (sand, whatever); with the inorganic proportion accounting for considerably more than the organic. But the answer is correct overall; if the titans are a natural part of the environment then "plants" would have evolved to use them as a substrate with wind-borne spores/seeds carrying them between titans. $\endgroup$ Jan 29 at 17:40
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    $\begingroup$ @JackAidley Good point. I've updated my answer to differicate soil and compost to make my meaning more clear. $\endgroup$
    – Nosajimiki
    Jan 29 at 18:16

From Wiki : Agriculture encompasses crop and livestock production, aquaculture, fisheries, and forestry for food.


1. Easiest

  • fishing
  • fishing farms (may be our water friends love rotten titan meat?)
  • we can use your seabed depths to aquaculture kelp (eradicating natural consumers and arranging seabed to have better crop)

2) Medium :

  • creating farms/befriending bigger fishes upon smaller/not eatable (for us) smaller sea riches

3) Harder (up to you)

  • what is titan made off?
  • how long his "meat" will root?
  • how long it will take to fall of from skeleton?

With knowing above we may consider gathering some sand (perfectly earth) and fertilization it with birds guano - everything on a top of dead titan or some boat/ship (where heavy rains/big waves can put end to our work).

I assume in original question you tough only about agriculture as planting and gathering plants - and in such case we are in hardest scenario and you have to also answer bigger questions

  • how your civilization keeps plants/seeds safe?
  • where we get wood to build our ships? (titan bones?)

Yes, depending on how deep the water is. If it's not too deep in certain areas, they could move stones/sand to form the borders of an enclosed area whose height is above sea level, use some kind of cement/putty/sticky material to block the gaps, then carve the titan's bones into an archimedes screw and pump the water out. Then you'll have land below sea level. This is just like how the Dutch have reclaimed land. You can also look up cofferdams, which is a similar method used to build bridges across water, but uses wooden planks. I'm not sure if there's any wood in your world, but if there is then it's definitely feasible. You could also maybe use their intestines as a siphon pump to remove water from the reclaimed land area. Bones and shells of aquatic creatures contain lime, which can be used to make cement also.


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