Suppose there exists a magic-based civilization. Their mining techniques are medieval and their understanding of organic chemistry and biology are on the Enlightenment era level. However, they are capable of creating portals, so they can establish stable supply of water and any needed materials.

This civilization has access to large supplies of niter (potassium nitrate), chalk, and peat. Will a combination of those, with minuscule additions of fishbone meal for phosphorus and steppe soil for microbial contamination purposes, be enough to provide an adequate starting base for a soil desert greening project?

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    $\begingroup$ There's more than just fertilizer and water required, it depends a lot on the character of the desert. Something like what you're describing would probably work wonderfully in a desert like the American Southwest. Not so much in the Sahara. Can you provide additional detail? $\endgroup$ Commented Jul 28, 2019 at 23:30
  • $\begingroup$ Seems like in a magic-based civilization, the miner would wave their magic wand and the copper, tin, aluminum, iron, etc. separate themselves, sort into neat piles, process into appropriate ingots or containers, and zoom through the appropriate portal away to the customers. All while the miner stays clean, enjoys a nice tea, and supervises the magic pen writing out the invoices to those customers. $\endgroup$
    – user535733
    Commented Jul 29, 2019 at 0:58
  • $\begingroup$ @user535733 Well, mine world is not that heavy magical. Magic there is mostly pseudo-sci-fi stuff: telekinesis (including stable levitation), teleportation (including stable portals), telepathy, body cultivation and use of some exotic materials. Not "wizard said spell and water turned into wine" kind of magic civilization. $\endgroup$ Commented Jul 29, 2019 at 1:34
  • $\begingroup$ usual deserts have a water problem - either not enough influx (too high to recieve rain or rivers), or too much eflux (evaporation because of dry air or high temp) - for the influx limited ones, a portalled river will do a lot of good. for the evaporation deserts, the water will leach the salts to the surface, creating a inhospitable salt crust. $\endgroup$
    – bukwyrm
    Commented Jul 29, 2019 at 5:25

3 Answers 3


Yes, peat, water and nitrogen fertilizer will go a very long way to making nearly any kind of desert land bloom even without the rest. As a comment noted, it's a lot easier if you start with an arid area having some sort of soil rather than nothing but sand, but its doable in either case.

The first thing to remember is that organic matter is not needed -- hydroponics works perfectly well without soil, so with adequate water and nutrients even sand will support plant life. (And will quickly enough build up soil.)

In most arid regions, the main thing lacking is water, and adding water alone will cause it to bloom. Add trace nutrients as needed.

Two caveats: First, some arid regions are salt flats. They're pretty hopeless unless you bury the salt fairly deeply. Second, while adding water will make many arid areas to bloom, that's not sufficient to grow, say, corn or wheat or rice which have fussier requirements. But even those plants can be induced to grow with the right mixture of peat into the soil along with micro-nutrients and a steady, plentiful supply of water.

  • $\begingroup$ It can also be tricky to KEEP the water where you want it, at least initially. Water doesn't stay put in desert soil, it runs off VERY quickly, so if the objective is to permanently turn the desert into a dry savanna (for example), you'll probably need ways to keep the water from just all rushing off through the sand and rock right away. Making REALLY BIG planters out of impermeable stone or something would help things, I would think. $\endgroup$ Commented Jul 29, 2019 at 0:01

Bring soil.

In the real world, fertilizer / soil amendments are nice because you do not need to transport as much mass from where it starts to wherever your farm is.

If your people have portals, transportation becomes much less problematic. Just bring soil from a place that has nice fertile soil, like a steppe or prairie or river valley. Put that on top of whatever soil your desert has. If your farming practices exhaust your imported soil, bring more from where you got it before and put that on top.

  • $\begingroup$ While bringing fertile soil from somewhere else sounds as very attractive solution, I think it a bit self-defeating scenario: why would nation that has access to large quantities of fertile soil try to use it to green the desert, rather than start agriculture right on a spot? Also I don't want to create green ecosystem in one place, while destroying it in other. $\endgroup$ Commented Jul 29, 2019 at 1:42
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    $\begingroup$ That desert nation does not have fertile soil. Nor does it have deep ocean seawater. It takes both soil and seawater from someplace outside its boundaries. A place like a wet river delta would not be farmable or even inhabitable but it would have lots of great soil. Portal in your soil from someplace with plenty to spare. $\endgroup$
    – Willk
    Commented Jul 29, 2019 at 21:39

Depending on how these portals work, you could make some portals under sea level so water would spew over the desert ground. If the volume of water was great enough to beat the rate of evaporation and soil drainage or if you had built some rocky substrate to prevent some drainage, you'd get a neat saltwater river, lake or, better yet, cannal system. Around these you could grow Salicornia. Some varieties are tasty even raw. In the saltwater itself you could grow edible seaweeds and small animals like crabs. Rather than requiring fertilizer, this could help your people save on it. Much of the phosphorus we are using to fertilize our crops is draining away to the bottom of the sea, so it isn't an easily renewable resource.

You could use freshwater instead but I imagine someone on the other side of that portal would be pretty upset over it.

  • $\begingroup$ I already established the way to provide my desert colony with unlimited amount of freshwater, see here $\endgroup$ Commented Jul 29, 2019 at 23:29

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