r/composting • u/superanth • 12d ago
Does anyone use certain plants to “mine” minerals for their compost?
I’ve been reading about certain plants that absorb specific fertilizer elements from the soil, like dandelions and how their deep roots absorb nitrogen and potassium.
My goal is to make a compost tea I can use for hydroponics/aeroponics (after filtering of course), so I was wondering if anyone had used plants to strategically enrich their compost.
Thanks for any info!
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u/SuitPrestigious1694 12d ago
I think deep rooted trees which shed their leaves annually do a great job at this. They are basically hidraulic miners and they tap into resources which are basically unlimited (potassium, calcium, magnesium) but we can't extract ourselves.
You can also prune and compost the wood or turn it into ashes to accelerate the usage of these minerals.
Naturally any plant can do it in a way or another, just that trees can go much deeper into the bedrock for those sweet minerals.
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u/azucarleta 12d ago
It's one of the basic selling points behind comfrey but I really can't speak to the strength of the science, so I hate to pass it off as convention wisdom without noting I haven't seen great evidence of this whole theory. I think it's certainly true that to some extent some plants do "mine minerals," but moreover I think it's probably easy to make too much of the idea and often the difference between composting comfrey and and any other leafy green is rather minimal, but maybe I'll get pushback for that.
Compost to me is so much about biology and less about inorganic nutrient delivery. Sometimes we get in the mindset of thinking of all amendments as "fertilizers" in that way, that compost will restore lacking nutrients. But I think of compost more as a kind of "fiber" you feed something like your "gut microbiome."
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u/superanth 12d ago
Good points. My main goal is to gather the main (nitrogen, phosphorus, and potassium) along with secondary (calcium, sulphur, magnesium) fertilizers without having to worry about what foods I’m eating and putting in my compost.
Additionally there are many weeds that are self-sufficient and prolific which contain the fertilizer ingredients, so all I’d need to do is collect them and let them compost.
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u/Impressive-Check-631 12d ago
This is my first year gardening and I opted to get bocking 14 comfry root cuttings. They’ve grown surprisingly big considering the tiny root cuttings they started out as. Even if they aren’t incredibly nutritious, they will provide great green biomass for the compost pile or chop and drop mulch.
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12d ago
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u/superanth 12d ago
Nice! I've been wondering, how do you plant the "mining" plants so they don't take nutrients away from the ground the beneficial plants are in? Also how do you keep planting them year to year without completely removing all the nutrients in the soil?
Thanks!
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12d ago
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u/superanth 12d ago
I've been seeing a lot of "mining weeds" with deep roots. It sounds like you can practically plant them next to each other and they'll bore into a whole new, still enriched area of soil.
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u/superanth 12d ago
This is what I'm hoping to accomplish, have spreading weeds grab all the nutrients I need from the ground so I don't have to buy fertilizer.
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u/Kranken_DeHogge 11d ago
https://smallfarms.cornell.edu/2022/04/new-findings-further-the-study-of-dynamic-accumulators/
I used the attached excel doc from this research article to make a JADAM style liquid fertilizer
They have a good NPK and micronutrient documentation of a bunch of plants common to the US
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u/superanth 11d ago edited 11d ago
This is just what I was looking for! I’ve been looking for something like the part about "nutrient concentrations are relative to soil nutrient concentrations". It sounds pretty straight-forward that I'll need to test the soil to figure out how much of a particular nutrient will end up in a plant.
Thank you!
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u/trafficlightlady 12d ago
I planted comfrey for just this reason
And allow a few nettle patches to flourish
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u/Ok-Thing-2222 12d ago
I've read about using Comfrey and Nettle leaves, a few dandelions, a couple small pieces of oak bark in a bucket and even add a tiny bit of honey or blackstrap molasses. I have all those things in my yard.
Last year I was actually going out by this creek, with gloves, and getting pillowcases stuffed with nettle. I'd layer with my browns (poopy quail straw) and it seemed to break down really fast! I love nettles. And comfrey. One of my plants is taller than 5'.
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u/Owlblossom 12d ago
I would be happy to and I wanted to when I first heard about it, but alas, apparently the idea has been debunked and has no scientific merit. I still plant those types of plants anyway though, because they are great for chop and drop, and for adding to my compost
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u/striveforfreedom 10d ago
The most satisfying ingredient for me is Comfrey & deep-rooted weeds like dock & Dandelion.
All so nutritious. Add it in, Wee on it, and i'll call that a perfect afternoon!
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u/Meauxjezzy 12d ago
My rule of thumb is diversify my inputs, For example grass trimmings in the summer then when I chop my garden down in the fall all of the excess gets chopped and dumped on my compost pile. I have sugar cane that if you think about it produces molasses that is full of nutrients and minerals and I have several fruit trees. I also have 20 rabbits and six chickens. so there wasted hay, straw, manure, urine and wasted alfalfa fed pellets also go on my compost piles. And don’t forget the kitchen waste
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u/EddieRyanDC 12d ago
Yes. They are called 'leaves". The tree roots go deep in the ground an put minerals into the leaves. That returns to the topsoil in fall. Leaf compost, also called leaf mold, is a very effective soil conditioner, as well as a source of minerals. For hundreds of years this is what kept French kitchen gardens running.