2

<this is a "what if" question instead of "fix a problem" one>

Correct me if I'm wrong: the major functions of soil(a bunch of tiny stones with some dirty stuff in between) to plants are:

  • anchoring point
  • a sponge-like substrate for the "dirty stuff" to be stored until the roots take it up
  • said sponge also preserves at least some of the water
  • and despite all those allow the roots to still breathe air.

I recently learned that an estimate on the time charred wood rots fully is 100 000 years. Same(and others) article also insisted the char is actually quite beneficial "for soil texture".

And now for the leap of reasoning. Imagine you take 5kg embers and grind them roughly(so as not to turn to ash). Then mix organic matter and plant something.

Would this "soil" work?

Vorac
  • 1,248
  • 1
  • 9
  • 16
  • 3
    Soil is so much more than the four bullet points listed. For one thing, you're missing the entire microbiome. – Jurp Jan 21 '24 at 14:09
  • 2
    Using 10-20% coarse charcoal is an established addition to soil. – Yosef Baskin Jan 21 '24 at 15:22
  • 1
    @Jurp sterilized soil is still called soil, right? And just left to it's own devices it develops said microbial life. So would a bucket of ground char develop the same given the same amount of nutrients are introduced? – Vorac Jan 21 '24 at 16:48
  • 2
    Sterilized soil, when used for potting up plants, requires fertilizers to feed the plant that is potted in it. There will be no microbiome in a pot, whether the pot contains char or basic soilless mix. If your intent is to plant houseplants in pots, then you'll have to watch your drainage and provide all nutrients via fertilizer. If your intent is to use ground char as a soil replacement outdoots, then your plants will suffer. – Jurp Jan 21 '24 at 17:04
  • 2
    Soil is also chemistry (the nutrients), not just a sponge: microbial life helps to decompose minerals into small particle roots can absorb. (reserve and available nutrients are both important stuff in soil analyses). No microbial life? So you need fertilizers with simple molecules. Coal: there are different types, just check online the components: you need C, P, K, N, but also many minerals. But IIRC also a lot of Ca, which may not be ideal for many plants. Often it is just a question of balancing all stuffs. – Giacomo Catenazzi Jan 22 '24 at 10:20
  • 1
    You have to watch pH too; from what I could find, activated charcoal has a pH of 7, so is neutral, but wood ash is much more alkaline. – Jurp Jan 22 '24 at 21:56
  • 1
    grind them roughly(so as not to turn to ash). That's not how ash works. Ash is (alomst) fully burnt in the presence of oxygen, mostly carbonates, while biochar is pyrolised in the absence of oxygen. Traditional charcoal making starts with a fire in air, then smothers it with insulating soil, so it stays burning hot but soon uses up all its oxygen. Ash provides nutrients but as @Jurp says is alkaline, so is to be used sparingly in most soils. – Chris H Jan 23 '24 at 21:29

0 Answers0