Following the "Generic apocalypse-causing event" most of Earth's population is wiped out in a matter of days. The several hundred survivors of Metropolis City salvage canned food from abandoned supermarkets, collect rainwater in plastic tubs, and burn furniture for cooking and warmth.

Over the coming months these survivors find each other, and migrate to the edge of the city where they hastily construct a small garrison, to defend themselves and each other against the zombie-terminator droids that still run rampant.

The garrison has access to salvaged tech but has difficulty building anything new. Since there are so few survivors, they can recover as many clothes, preserved food and medical supplies, guns and bullets and so forth, as they need from the abandoned city. But on the other side, the wall of their town is made of stacked up dead cars rather than bricks and mortar.

With this in mind I wonder: What are these guys eating?

They will be fine for a number of months or years eating canned and preserved food. But eventually that will run out, and they must grow their own food. This is easy at first. Just find working farm machinery and plant crops. But the fuel for the vehicles will expire after several years or months. So it's realistic they can plant a first round of crops, but mechanized farming is unsustainable in the long term.

So what is the best case scenario for how the world looks in 10 years after all the petrol and canned food has run out? The worst-case scenario is they revert to sustenance farming by hand, perhaps with access to more efficient crops than in the middle-ages.

However this presents story obstacles since (i) they need to defend a larger area from the remaining zombie terminators. This takes away from the "handful of survivors huddled together against an unbeatable enemy" vibe that is common in this sort of setting and (ii) it is harder to set a story in a world where everyone spends all day in the fields and has less time for plot-related action. It is harder for my rag-tag bunch of heroes to sneak out and defeat the undefeatable enemy when they are expected to spend all day every day growing potatoes to feed their families.

Edit: Since we are looking for a best-case scenario, please assume any helpful conditions you like. For example good farming climate and access to animals that can pull a plough or be ridden.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch
    Mar 27, 2021 at 17:01

5 Answers 5


the best case scenario 50% of your people are farmers, 70% is more likely.

My assumption is that best case scenario means the most food least amount of land and labor. I also assume they are in a suitable kind of climate and terrain. Also that the survivors managed to get a hold of the right equipment since cities are not known for having large supplies of old agricultural equipment lying around. I also assume a population in the thousands.

They will need to do a lot of wall building, collecting, cataloging, and sorting in the first few years. On the up side they will have a lot of fuel available at first, fuel that will not last plus access to heavy machinery and stored food so it should not be too hard.

Fuel is less of a problem than keeping the machines working, they can build coal/wood gas engines from parts, but the parts will wear out, they might last 50 years depending on how many they need to keep running. If they hoard lubricant and have a good mechanic a lot longer. The replacement for tractors is oxen and a wheeled steel plow. The more useful experts they have the better, agriculture, engineering, chemistry, and electrical engineering will be very important skills. A really clever engineer might be able to make/salvage a few steam engines in the beginning when material is abundant.

Modern crops will help, especially some of the genetically engineered ones that are pest or drought resistant. I am assuming the bulk of the crops are cereals since they give the best production for the least effort and land, and store well on top of it. you of course will want a selection of fruits and vegetables as well as fishing or livestock to keep it nutritional, most cities are built in places were fishing at least is possible. How good are your zombies at swimming? goats and pigs make excellent livestock since they are not picky about food, pigs breed faster but goats can give you milk and cheese. they will need to actively breed oxen to keep them around so they will have beef too.

They will need to build waterwheels and/or windmills to pump water and mill grain, but they have a lot of material to build them and the tech involved should last a long time. in the right place they may already have some, there are small dam water generators scattered all over the world. On the upside if they stockpile pipe they can make it last for hundreds of years. they will run out of bullets long before they run out of pipe. If they get lucky and have the right kind of bamboo they can make OK pipe. So they should have irrigation.

they can build greenhouses, since glass will be plentiful, this means they can live above the mosquito line and produce food all year long. This also means they can build solar water purification which will be a big help for saving fuel. You will still need a steady supply of fuel either timber or empty suburbs with wooden homes for cooking and vehicles. A few train cars full of coal will go a long way to keeping vehicles running.

hopefully they will have engineers who can make mechanized animal powered threshing, they will have plenty of scrap and parts to work with. Maybe they can build a simple steam engine as well which could provide electricity which will make it all a lot easier, alternatively they could have a working hydro-generator, as I said there a quite a few small scale ones out there.

Your biggest problem is lack of industrial scale chemistry, no artificial fertilizers or pesticides. No matter what you do most of the people will be farmers, becasue losses will be high. You just can't get huge food surpluses without mechanization, fertilizers, and pesticides. there are simpler pesticides they can make but they will require mining and will kill a lot of farmers. Maybe they can breed pest predators to help. Without fertilizers they are back to crop rotation which drastically increases the amount of land they need to defend.

Scale will effect this, larger populations can potentially produce some industrial chemicals but it will be harder to keep enough machines running.

Combine all of this and you are looking at 1800's technology at best, during the 1800's between 70-50% of the the population of the US were farmers. you will have some better tech in some places worse in others, lower population impedes technology so don't expect trains and factories, but some existing practices will still work offsetting this, pasteurization and canning for instance will greatly increase food preservation.

You may want to look at British war time farming, for which fuel rationing forced less mechanization while maximizing food production, and prevented a lot of manufactured goods from being used. I would still expect half your people to be farmers in 10 years, with this increasing as alternative fuels and equipment run out. But note farmer does not mean they can't do anything else farmers can still defend their walls, help build things, hunt, and fish. For ten years they can easily keep mechanized farming running off modified vehicles and electric pumps and hydro-electricity. 50 years out they will need to more animal power and hydro-mechanical pumps. If the population is small they should still have a few coal/wood gas running vehicles.

  • $\begingroup$ Most places, you don't need irrigation at all. In the US, certainly anywhere east of the Mississippi, or the Pacific Northwest. Even where you need irrigation, you don't need pipes. Flood irrigation works just fine - various Southwest Indian tribes used it hundreds of years before Europeans showed up. $\endgroup$
    – jamesqf
    Mar 25, 2021 at 17:37
  • $\begingroup$ @jamesqf to get the same yield irrigation is important, flood irrigation has many problems not the least of which is rapid erosion, requiring large amounts of water, and requiring extensive leveling of land. More importantly only works well for certain crops. $\endgroup$
    – John
    Mar 25, 2021 at 21:26
  • $\begingroup$ "50% of your people are farmers, 70% is more likely" what's the % for the Amish? they'd probably make a good baseline rule of thumb for this. $\endgroup$
    – Pelinore
    Mar 26, 2021 at 1:17
  • $\begingroup$ @Pelinore you do realize the Amish use modern technology right? There culture precludes frivolous use of technology. Many use tractors, front end loaders, ect. Others work in factories. $\endgroup$
    – John
    Mar 26, 2021 at 15:08
  • $\begingroup$ @John: But you don't need irrigation (again, in most places) to grow a reasonable food supply for a small population, you only need it if you're trying to maximize production in industrial agriculture. WRT flood irrigation & land leveling, you seem to be thinking about industrial scale, as in e.g. California's Central Valley. I'm talking about small-scale things, as practiced by those southwest peoples, or FTM my neighbors today, who irrigate their pastures with a ditch from the local creek. $\endgroup$
    – jamesqf
    Mar 26, 2021 at 16:13


Using PVC tubes

That gives a greater yield per area than traditional farming. The killer is grabbing enough technical-oriented people to set up the supply chain.

  • 3
    $\begingroup$ only works with modern technology. you need mechanization, chemistry for nutrient control, its not really feasible for low tech. $\endgroup$
    – John
    Mar 25, 2021 at 16:51
  • 2
    $\begingroup$ "That gives a greater yield per area than traditional farming" also more labour intensive once you factor in all the production & maintenance for the systems & additional equipment needed // but smaller areas are easier to defend so depending on the scenario you might get a net reduction in man hours anyway. $\endgroup$
    – Pelinore
    Mar 26, 2021 at 1:27
  • $\begingroup$ @Pelinore you hit the nail on the head. Yield per Area is a security concern in that scenario because you can not eat what was stolen nor work on it if you die. $\endgroup$
    – Gustavo
    Mar 28, 2021 at 23:27

Abandon Farming

Note: This only works with slow, shambling zombies that don't infect animals. If your zombies are runner zombies, or they infect dogs, then I'm sorry EVERYONE is a farmer, and action hero antics happen on what would be considered 'off time' for other societies.

Farming societies have, on average, less free time than hunter-gatherer societies. Societies that perform primarily farming work around 30 hours a week, while hunter-gatherers work closer to 20 hours a week.

You may ask why society might have shifted to agriculture at all, and the reasons are extremely complicated and likely have to do with a combination of risk-aversion and population densities.

In a post-apocalypse, however, population density is not a problem. The Chumash are able to support their hunter-gatherer culture on a population density approaching 21 persons per square mile.

You can fit 10 times as many people in a small space with agriculture, but you need to have positive control over the entire region in order to farm, as opposed to hunter-gatherers who can cover an enormous radius by just avoiding the more dangerous parts.

From a survival perspective, this makes a lot of sense near the start of the apocalypse. Skills useful for hunter-gathering are also useful for finding equipment from the bygone era to scavenge. They also double as useful skills for hunting/avoiding zombies.

From a story perspective, this is also far more cinematic. There's nothing to stop farmers (who only need to work around 30 hours a week, mind you) from also fighting back against the zombies from behind their nice, safe walls. There is, however, something altogether more exciting about having bands of hunters leave the safety of the outpost, armed to the teeth in whatever makeshift weapons and armor they can manage, in order to hunt prey, set/inspect traps, gather relics from the technological age, and put down whatever infected they can find.

  • 2
    $\begingroup$ what are they going to hunt or gather, in any (previously) civilized region? $\endgroup$
    – ths
    Mar 26, 2021 at 0:24
  • $\begingroup$ "Farming societies have, on average, less free time than hunter-gatherer societies" you're mistake is uncritically accepting the articles attention getting title at face value & extrapolating their observed results for all other climates, different climates make a serious difference, somewhere tropical where wild crops & wildlife is ultra abundant & flourishes year round adopting agriculture may be counterproductive, but that's unlikely to hold true in other regions. $\endgroup$
    – Pelinore
    Mar 26, 2021 at 1:13
  • $\begingroup$ "In a post-apocalypse, however, population density is not a problem" it is for hunter gatherers if the low population density extends to potential prey animals, the lower the density of prey the more time you have to spend looking for the damn things b4 you can have lunch // if it's low enough it becomes completely unviable compared to farming from a man hours perspective .. sorry, just had to point that out :)) $\endgroup$
    – Pelinore
    Mar 26, 2021 at 1:39
  • $\begingroup$ @ths Well... people? At least in the first years. You get their belongings and have them for supper as a plus. Provided this doesn't risk turning you into a 'zombie' too. Meanwhile hopefully wildlife will manage to increase in numbers and expand on territories previously managed by humans. $\endgroup$ Mar 26, 2021 at 11:58
  • $\begingroup$ By the time they've gotten through that first year (planted and harvested with leftover, still-working machinery) there'll be plenty of dogs and cats, escaped chickens, etc. The chickens are obvious (and yard chickens are much smarter and more capable than cage laying hens), dogs and cats convert critters and stuff humans can't catch or won't eat into edible meat (same way chickens do, but different stuff). $\endgroup$
    – Zeiss Ikon
    Mar 26, 2021 at 18:38

I dont think youll go back.to.50-70% farming, at all

There was a city. Cities have satellite towns and infrastructures. There are now a few hundred people. Conclusion, there's a hell of a lot of gear, storage, and prebuilt materials, laying around. Much or most of it will be protected from the elements.

The survivors will try at first to stay with what's easy and familiar. They wont choose mass farming or hunter-gatherer unless they feel obligated to, in the face of necessity/inevitability. They'll try other things too.

A group of a few hundred will have a wide range of skills.

My guess is, you'll see a society based on scavenging, and on safeguarding/stockpiling assets that can't easily be replaced like spare parts, generators and fuel. Some petroleum based fuels will degrade; others wont if stored carefully. Water can be separated even from the more volatile fuels (neat trick I once heard, Stephen Kings "The Stand" maybe?? unsure how accurate - add sugar: dissolves in water not fuel, water becomes denser and sinks, take the top 80% and it'll be usable).

I expect in the first few years, as they take stock and realise resources must be used sparingly, they will for example use horses to scavenge further out, or battery radios to communicate with outposts, but save fuel for key generators and key tools, not for heat and light. Medicines and cold dry storage will be important, food preservation will become common. Books with important knowledge will be crucial. That sort of thing. Teams will be established to find the key raw materials and safe places for them, and once basic survival is secured, teams led by those with past knowhow will set up rudimentary manufacturing and production systems to service cars and other machinery.

Why will they do that, and is it practical long term? Look at places like rural India and Africa, where there is a huge reliance on fixing up old machinery and cars, often decades old, and making them work by patching them. So I'd say, yes. They can and it'll work. They will discover that, when a useful item breaks and some mechanic says "I can probably jury rig a repair". They'll get very good at those.

They won't need to lose mechanisation because being several hundred people in a city they have enough resources and skills to.survive the immediate aftermath and live on local resources while they transition to.a scavenger society, which will keep the going long enough to transition to simple manufacturing and collectively organised small scale industry. There will be dozens to hundreds of places with diesel/kerosene/petroleum fuel storage, hundreds of workshops and engineeringechanics places..... I don't see them having any issues making that work, and that'll be the first thing they try. For example, you might not have microchips for modern cars, but you'll be able to find ways to make enough vehicles go (modding if needed), that it'll work for their needs. A city will have plenty of pre-microchip era vintage cars, or cheap trucks, or fork lifts, or other items, and their spare parts, in good condition. Ditto generators.

Your challenges are not difficult ones.

I think social issues (how they organise) falls under "best case", we assume they can organise in a way most are OK with. Or those who aren't, leave or die, or accept its their best chance anyway, or live in fear but obey. The city is more than big enough if they split into 2 or 3, and trade will be possible unless they are in a TV drama where everyone is irrational.

Food will in the first instance be scavenged and stockpiled, and later will be collectively scavenged and centrally rationed. Longer term they will need to produce food or hunt, but they'll have mechanised tools, and we can assume nature will reclaim so they can corall off an overgrown area and meat production is easy - salt/smoke and dry and you have winter food. Why meat emphasis? Its denser nutritionally, and far less work (keep them in a limited area and let nature take care of plant growth to feed them, and reproduction, 1 or 2 people per herd and lots of temp help at slaughter time), and they have the resources to support it.

Obligatory zombies - well, think how widely available munitions and fire, and defences, will be in a city. Scavenge at gun shops (US only), police stations, army buildings, or make your own crudely - bear traps, flamethrowers and soap based napalm equivalents... You just won't run out of supplies for those for a few years, and by then you'll find other solutions that won't run out. No problem.

Eventually stuff will wear out that can't be replaced, but the number of things that are essential to their present living will be small, and they will see it coming years away. Yeah, those lithium ion battery tools won't last as we can't fix batteries. We can stockpile a few thousand from houses and shops and industrial buildings, and charge them monthly, off generators and kerosene, and enough will last long enough to use their power tools for maybe 15-20 years. (I just bought a power tool with a 2014 battery, works fine). They'll run low eventually but with enough warning (years) to figure what they'll do instead. So time won't be as big a problem as it may seem.

Likewise living spaces. Yes houses and buildings degrade over years and decades, and eventually collapse, but not for a looong time. The masonry/concrete structures often last well, and you don't need to do much to prevent it or jury rig workarounds for the roof or timber windows that fail. So warm and dry spaces and storage are easy too.

Overall if they can work together, they should be okay.

  • $\begingroup$ meant will be hard to come by unless they have livestock or resort to eating rats. there is not a lot of food in cities without humans importing it. $\endgroup$
    – John
    Mar 27, 2021 at 16:08
  • $\begingroup$ @John The question says the survivors migrate to the edge of the city. Typically there are farms at the edge of cities. $\endgroup$
    – Daron
    Mar 27, 2021 at 16:20
  • $\begingroup$ the edge of most modern cities are suburbs, which do not have much wilderness. it is hard to feed a population of any size off hunting alone, nor is it healthy. Also fuel stores will not last long becasue the fuel itself will go bad. the shelf life of gasoline and diesel is less than a year. $\endgroup$
    – John
    Mar 27, 2021 at 16:23
  • $\begingroup$ the edge of most modern cities are suburbs, which do not have much wilderness. it is hard to feed a population of any size off hunting alone, nor is it healthy. humans will quickly depopulate all the huntable animals if that is all they are eating. Also fuel stores will not last long becasue the fuel itself will go bad. the shelf life of gasoline and diesel is less than a year. $\endgroup$
    – John
    Mar 27, 2021 at 16:29
  • $\begingroup$ The question says to assume best case. But we don't need unusual luck. Cities are remarkably green - even in the centre or suburbs. House gardens, sports arenas, street verges, parks.... Look carefully at a city like London or NYC on Google satellite, for realism. Cities are plenty able to support animal herding on a small scale, if you want to and theres only a few hundred of you, and travel for 5 or 10 miles to move place to place nearby, isn't hard in this scenario. $\endgroup$
    – Stilez
    Mar 27, 2021 at 18:01

Consider nomadic harvesting.

You will have a population of a few hundred, on a planet that had farms capable of supporting several billions.

The specified apocalypse (zombie terminators) would not do anything to destroy existing farms, orchards, etc.

So you have huge tracts of land planted with foodcrops, totally untended. They will be harvestable! Obviously not nearly to the level of quality or yield that a healthy, tended farm will give, but still a lot better than a true wilderness would. (and wildernesses are vastly undervalued as food-sources!)

Just have your people migrate around, set up camp and strip-mine the region for valuables, both scavenged material and food, then move on once a local region is depleted.


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