5 ms·

In case this didn't make a lot of intuitive sense to you engineering/physics/landscaping/agriculture types: Mexico City's "Floating Gardens", chinampas, do not

by mapt 2y ago

In case this didn't make a lot of intuitive sense to you engineering/physics/landscaping/agriculture types: Mexico City's "Floating Gardens", chinampas, do not actually float, and never have. They're reclaimed land, or artificial islands, masses of compost & soil initially retained mostly by stockades of wooden stakes stuck into a shallow lakebed, then gradually filled.

chabons 2y ago
Here I was scanning the article for what they floated on. I had assumed it was a peat-bog type situation. I guess the key benefit of this strategy is that the water level is high and the water is nutrient rich? Otherwise it's pretty similar to a standard canal irrigation setup.
- throwup238 2y ago
  They replenished the dirt on the islands with night soil dredged up from the bottom of the lake every year so it was basically a mound of fertilizer that’s always soaked through with water. It’s as close to an ideal growing condition as pre-industrial societies had.
throwup238 2y ago
I have no idea where this idea of chinampas as floating gardens came from but it’s an enduring myth. Floating gardens using soil are practically impossible - the displacement required to keep enough earth floating for a root system is massive. The chinampas worked very well because the Aztecs had a large labor force cleaning their latrines into the lake where it would decompose into night soil and later be dredged up to refill the chinampas between growing seasons. Once they were built up within the underwater stakes, they planted Ahuejote and Ācātzin trees along the edges and corners whose root systems kept the islands from eroding away.
- bliteben 2y ago
  > Floating gardens using soil are practically impossible but very cool when they do exist https://en.wikipedia.org/wiki/Floating_island https://en.wikipedia.org/wiki/Floating_island
- g8oz 2y ago
  In Lake Titicaca, (Peru/Bolivia) floating islands are made using beds of reeds https://www.bbc.com/travel/article/20220814-the-floating-homes-of-lake-titicaca https://www.bbc.com/travel/article/20220814-the-floating-hom...
  - aetherson 2y ago
    But note the difference: they aren't floating gardens, they don't carry enough soil for the root systems of plants. They're large rafts that have houses/people on them.
    - hrisng 2y ago
      Chinampas is not truly floating. But you can absolutely have a true floating garden, as long as the water is fertile and has enough oxygen in it. Plant roots can survive in water or in water-logged conditions, dissolved oxygen is often the limiting factor. You can have a layer of soil in your floating garden too. You can mix in amendments that will make your soil very light and fluffy. A bunch of empty bottles/jars make a pretty good floating raft that can handle some weight. May not be the best if you have concerns about microplastics in your food, but that is what they've been using here in the Mekong Delta.
      - hrisng 2y ago
        This article has some photos of the mentioned setup in it: https://tienphong.vn/doc-dao-trang-trai-rau-sach-tren-be-lam-tu-rac-thai-nhua-post1552286.tpo https://tienphong.vn/doc-dao-trang-trai-rau-sach-tren-be-lam...

by mapt 2y ago

chabons 2y ago

Here I was scanning the article for what they floated on. I had assumed it was a peat-bog type situation. I guess the key benefit of this strategy is that the water level is high and the water is nutrient rich? Otherwise it's pretty similar to a standard canal irrigation setup.

throwup238 2y ago
They replenished the dirt on the islands with night soil dredged up from the bottom of the lake every year so it was basically a mound of fertilizer that’s always soaked through with water. It’s as close to an ideal growing condition as pre-industrial societies had.

throwup238 2y ago

I have no idea where this idea of chinampas as floating gardens came from but it’s an enduring myth. Floating gardens using soil are practically impossible - the displacement required to keep enough earth floating for a root system is massive. The chinampas worked very well because the Aztecs had a large labor force cleaning their latrines into the lake where it would decompose into night soil and later be dredged up to refill the chinampas between growing seasons. Once they were built up within the underwater stakes, they planted Ahuejote and Ācātzin trees along the edges and corners whose root systems kept the islands from eroding away.

bliteben 2y ago
> Floating gardens using soil are practically impossible but very cool when they do exist https://en.wikipedia.org/wiki/Floating_island https://en.wikipedia.org/wiki/Floating_island
g8oz 2y ago
In Lake Titicaca, (Peru/Bolivia) floating islands are made using beds of reeds https://www.bbc.com/travel/article/20220814-the-floating-homes-of-lake-titicaca https://www.bbc.com/travel/article/20220814-the-floating-hom...
- aetherson 2y ago
  But note the difference: they aren't floating gardens, they don't carry enough soil for the root systems of plants. They're large rafts that have houses/people on them.
  - hrisng 2y ago
    Chinampas is not truly floating. But you can absolutely have a true floating garden, as long as the water is fertile and has enough oxygen in it. Plant roots can survive in water or in water-logged conditions, dissolved oxygen is often the limiting factor. You can have a layer of soil in your floating garden too. You can mix in amendments that will make your soil very light and fluffy. A bunch of empty bottles/jars make a pretty good floating raft that can handle some weight. May not be the best if you have concerns about microplastics in your food, but that is what they've been using here in the Mekong Delta.
    - hrisng 2y ago
      This article has some photos of the mentioned setup in it: https://tienphong.vn/doc-dao-trang-trai-rau-sach-tren-be-lam-tu-rac-thai-nhua-post1552286.tpo https://tienphong.vn/doc-dao-trang-trai-rau-sach-tren-be-lam...