Soil building for nutrient density

[COMPOSTER]

Dice,

Very interesting aout the ashes and humic acid. Having the ability to experiment can really teach us a lot. I think many gardeners focus too much on fertilizing the plants and not on taking care of the soil so the soil takes care of the plants. This forum is a great place to learn that NPK is not all there is to growing healthy plants.

Any experience with rock dust?

Glenn

[simmran1]

Glenn and all subscribed,

A very senior citizen (and block ½ away neighbor) has always gardened organically, and when asked about what he used his one constant response was granite dust. Cucumber plants, peppers and eggplant always had granite dust in and around each plant. He brought some over in 2007 when I was ready to plant and we treated half my tomato plants. I could not see a difference in growth or yield compared to the others with no granite dust.

I do use rock phosphate for tomatoes, peppers and when planting garlic cloves in the fall. I feel the garlic needs slow release nutrient availability through out the winter. I guess I could do a control group test since I have 2 garlic beds..., but partly any added nutrient translates in part to peace of mind knowing I've done my part toward a successful harvest.

[Master_Gardener]

Originally Posted by simmran1

Glenn and all subscribed,

A very senior citizen (and block ½ away neighbor) has always gardened organically, and when asked about what he used his one constant response was granite dust. Cucumber plants, peppers and eggplant always had granite dust in and around each plant. He brought some over in 2007 when I was ready to plant and we treated half my tomato plants. I could not see a difference in growth or yield compared to the others with no granite dust.

I do use rock phosphate for tomatoes, peppers and when planting garlic cloves in the fall. I feel the garlic needs slow release nutrient availability through out the winter. I guess I could do a control group test since I have 2 garlic beds..., but partly any added nutrient translates in part to peace of mind knowing I've done my part toward a successful harvest.

My understanding is that there must be adequate soil life for the rock dust to have an effect. Plants don't eat rock to the best of my knowledge. Also, I think that rock is a longer term solution. It's not like adding N.

[COMPOSTER]

Originally Posted by Master_Gardener

My understanding is that there must be adequate soil life for the rock dust to have an effect. Plants don't eat rock to the best of my knowledge. Also, I think that rock is a longer term solution. It's not like adding N.

From the articles and books I have read and am reading the most common way to use rock dust is to mix it into compost and then add the compost to the soil. This is what I am currently doing. The compost and any reasonable soil should contain quite a bit of microbial life and the rock dust is reported to cause a population explosion in the microbes. The microbes would then somehow make the trace elements available to the plants in a form they can use. The increased population of microbes would also continue to break down the compost or other material in the soil and make that available to the plants. So it seems that organic material and rock dust work harmoniously together to create a more fertil soil. I'm sure either used by themselves would provide a lot of benefits, but the 2 used together in significant quantities may greatly reduce or perhaps eliminate the need for purchased NPK products.

I know I have said it before but I think it is worth repeating. Rock dust is reported to significantly increase the nutrient density and enhance the flavor of produce.Thus it is more healthy and tasty to eat. Rock dust is a byproduct of the gravel industry and in many cases can be had for little money or for free. Rock dust if applied at the rate of 1/2 to 1lb per sq ft needs to be applied once every decade or so. As a gardener it almost sounds to good to be true. But it also seems logical that because of rain fall and use most of the soils we garden in have got to be somewhat depleted in trace minerals.

Glenn

[dice]

Any experience with rock dust?

I have not used granite or basalt dust (have not had any), but
I spread greensand and rock phosphate around about every
5 years. I would expect similar effects from rock dust, ie a long
term, slow-release source of potassium and whatever other
nutrients are in the rock (iron, calcium, magnesium, manganese,
molybdenum, etc). If your soil was deficient in any of those, you
could see dramatic effects from using it. (Although greensand
is not recommended for correcting the scale of potassium
deficiency that would show up in a soil test, and granite dust
would probably not be either for the same reason: too slow
release. But the point is for the deficiency not to show up
in the soil test in the first place, and any of these rock dusts
could help with that.)

Very little of the nutrients in rock dusts is "immediately available". Big
deal, that does not mean most of it will not be substantially available
over several years.

Some kinds of archaea will break down rock (make insoluble nutrients
soluble and thus available to plant roots), and people in Australia
planting trees have had dramatically better results with tree seedlings
in rock dust amended soils than in the same soils without the amendment.

It is not a "quick fix" fertilizer or soil amendment, just good insurance
that at least some of what all is in it will always be available to your
plants. (And earthworms in compost seem to be especially fond of it.
I do not know if it is the nutrients in it or simply the grit that they
thrive with.)

[mikeybear2010]

Originally Posted by Master_Gardener

Anyone for a soil test? How do you know what to add if you don't know what you have? My soil test indicated that I needed Iron, Zinc, Magnesium and a bit of Boron.

I'm with Master_Gardener!

This thread is supposed to be about soil building, but mostly seems to be about using rock dust. I don't use rock dust. I don't have anything against it, just don't have it available locally. If I did, I probably would use it.

Maybe I'm missing something here, but it seems to me the easiest and cheapest way to build our soil is good old home made compost. If you use a variety of materials in your compost you'll get the trace elements and micro-nutrients.

I use gosh darnoodley near everything that I can get, that will rot, in my compost heaps. Cow manure, Horse manure, Chicken manure, Elephant manure (when the Circus is in town for a few days), grass clippings, leaves, kitchen scraps (I've even been know to toss in a few meat scraps now and then), sawdust, shredded newspaper, fish heads and scales (buried deep in the center of the heap), shrimp and crab shells (same as fish heads), hair clippings (collected from the Barber Shop) . heck, I've even been known to toss my fingernail and toenail clippings in (I'm dedicated to compost)!

if you can't, or don't want to make your own, check your city landfill. Many places now have compost programs,and you can get it cheap or maybe free for the hauling.

I soil test every year and maybe I'm just lucky, but after the first three or four years, I've had few deficiencies and those were simple to correct.

I started with some pretty sorry sand, deficient in just about everything except sand. I put all the compost and organic matter I could into it, and now that soil looks like it was trucked in from somewhere else!

I'm lucky in that I have access to large amounts of Cow, Horse and Chicken manure. Wish I had access to large amounts Of Elephant manure! That stuff is great! I even approached my wife about buying an Elephant. She said "Sure, as soon as the divorce is final"! Guess she didn't think too much of the idea. Oh well.

If you're really serious about building your soil folks, I say compost, compost, compost!

That just about wraps up my rant. In case you haven't noticed, I'm sold on compost!

[RayR]

Originally Posted by Master_Gardener

My understanding is that there must be adequate soil life for the rock dust to have an effect. Plants don't eat rock to the best of my knowledge. Also, I think that rock is a longer term solution. It's not like adding N.

Without adequate soil life you're on your way to dead soil, and that is the problem with nutrient density in conventional agriculture. Plants do eat rock after the minerals have been made soluble and plant available by chemical and biological action. The minerals we get from our food comes from what the crops take up from the soil.
The problem with cultivated soils is that we harvest the minerals that have been taken up by the plant and if the soil is not replenished, sooner or later the soils will be depleted of many valuable minerals.
You're right that it's a long term solution, but that's the whole point of remineralization with rock dusts, even one application can supply essential minerals for years. Organic matter like composts can help replenish some minerals in the soil, but it's a short term supply and would have to be replenished repeatably.
Organic matter and rock minerals are inseparable components in sustaining healthy soil life. Using rock dusts is just an accelerated way of doing what nature does, the fine particles are more quickly broken down because of the larger surface area exposed to chemical and biological action.

[COMPOSTER]

Originally Posted by mikeybear2010

I'm with Master_Gardener!

This thread is supposed to be about soil building, but mostly seems to be about using rock dust. I don't use rock dust. I don't have anything against it, just don't have it available locally. If I did, I probably would use it.

Maybe I'm missing something here, but it seems to me the easiest and cheapest way to build our soil is good old home made compost. If you use a variety of materials in your compost you'll get the trace elements and micro-nutrients.

I use gosh darnoodley near everything that I can get, that will rot, in my compost heaps. Cow manure, Horse manure, Chicken manure, Elephant manure (when the Circus is in town for a few days), grass clippings, leaves, kitchen scraps (I've even been know to toss in a few meat scraps now and then), sawdust, shredded newspaper, fish heads and scales (buried deep in the center of the heap), shrimp and crab shells (same as fish heads), hair clippings (collected from the Barber Shop) . heck, I've even been known to toss my fingernail and toenail clippings in (I'm dedicated to compost)!

if you can't, or don't want to make your own, check your city landfill. Many places now have compost programs,and you can get it cheap or maybe free for the hauling.

I soil test every year and maybe I'm just lucky, but after the first three or four years, I've had few deficiencies and those were simple to correct.

I started with some pretty sorry sand, deficient in just about everything except sand. I put all the compost and organic matter I could into it, and now that soil looks like it was trucked in from somewhere else!

I'm lucky in that I have access to large amounts of Cow, Horse and Chicken manure. Wish I had access to large amounts Of Elephant manure! That stuff is great! I even approached my wife about buying an Elephant. She said "Sure, as soon as the divorce is final"! Guess she didn't think too much of the idea. Oh well.

If you're really serious about building your soil folks, I say compost, compost, compost!

That just about wraps up my rant. In case you haven't noticed, I'm sold on compost!

The thread was started to attempt to address the theory that soils can be built to increase the nutrient density in crops. The reason it has concentrated on rock dust is because there seems to be a significant body of scientific evidence that supports the depletion of minerals in soils for variuose reasons. As Ray R points out cultivation is a main reason but also just the leaching of minerals over the centuries as well. I am also a dedicated composter, but what if all the things we are using to compost were also grown on depleted soils? Certainly then our compost may not be putting the trace elemants and minerals back in the soil as we think and we need to explore other avenues. Rock dust seems to have a lot of potential to revitalize depleted soils and deserves to be seriously considered for those who want to provide the heathiest crops.

Glenn

[ScottinAtlanta]

OK, here is a question. Most people use compost piles as I do, but I have been reading about layering compost ingredients about 6 inches thick on top of the garden soil, covering with a tarp, and letting it compost right on top of the ground.

Views on that approach? It obviously would be done in fall as garden areas are cleared of plants.

[Redbaron]

Scott,
I do it, but I don't cover it with a tarp. I have some melons growing in one of them now. I made it in the spring and just waited for it to cool down before planting the melons right in it.

Ingredients are crop residue from over-wintering brassicas after harvest, horse manure, compost, Coffee grounds, top soil, heavy cardboard weed barrier, leaves, hay, sod plugs, wet fresh grass clippings, final layer of dried grass clippings as mulch after planting. All the ingredients up to leaves I used to heat my low tunnel to grow seedlings. I posted that in detail on another thread earlier this spring. Once the low tunnel was taken down I added the top layers about 3 - 4 feet thick. That heated up a few weeks dropping considerably. Then I planted directly into it. I did that by digging a 3 X 6 inch diameter holes (2 for melons, 1 for dill) into the compost pile and filling them with potting soil. I planted the seeds in the potting soil and mulched after they sprouted. The melons planted directly into the compost pile are many times larger than the ones planted with just a weed barrier and mulch just feet away. Huge difference. I also planted dill, turned out to be too rich for dill, it died back. However once it adjusted, it did sprout back up again from the same plant that died back. The dill is still small compared to the other dill planted in soil though.

I have been adjusting the method for several years now. This is the first year I went so extreme, and the first year I got such extreme results too. I may try it with tomatoes next year. But at least for melons it works great. Since the companion plant dill died back first then came back, I know for certain things it may be too rich. I'll continue my yearly experiment with new veggies every year. So far I have found out it has mixed results for brassicas, great results for melons, terrible results for potatoes (100% died), and still tentative on the dill but for sure a slow start.

PS. If you do it in the fall and plant in the spring it will probably work better for crops that don't like it quite so rich.

[dice]

Sheet composting with a layer 6 inches thick, that is what, an inch
of finished compost? Half an inch?

Probably works better on a loose, mostly organic or sandy loam
soil that already has a lot of nutrition in it than on heavy clay.
As "topping up", it may be fine. As "major soil renovation", that
could take many years to show results. That half an inch to an
inch of finished compost is going to be silt by the end of summer
in a warm climate (large pore air space challenged).

[COMPOSTER]

Originally Posted by ScottinAtlanta

OK, here is a question. Most people use compost piles as I do, but I have been reading about layering compost ingredients about 6 inches thick on top of the garden soil, covering with a tarp, and letting it compost right on top of the ground.

Views on that approach? It obviously would be done in fall as garden areas are cleared of plants.

Scott,

It sounds like an excellent approach and I plan to try this strategy in the Fall on a couple beds. I'm looking for an alternative to planting a cover crop and also to reducing the time spent on making and turning compost in piles. What better way than to compost right in the garden? I have only done a little reading on the subject but think you may want to think about using more materials than 6 inches thick. The one clear drawback I see is there will probably be limited heating of the materials which will allow all the weed seeds to survive.

Glenn

[Redbaron]

Originally Posted by dice

Sheet composting with a layer 6 inches thick, that is what, an inch
of finished compost? Half an inch?

Probably works better on a loose, mostly organic or sandy loam
soil that already has a lot of nutrition in it than on heavy clay.
As "topping up", it may be fine. As "major soil renovation", that
could take many years to show results. That half an inch to an
inch of finished compost is going to be silt by the end of summer
in a warm climate (large pore air space challenged).

It depends a lot on the materials. Things like grass clippings will decompose down to nearly nothing. My 3-4 foot mound this year is down to a couple inches already. And there is a layer of soil in them! Wood chips or bark fines hold up far better, but still reduce quite a lot.

Over all on average I do gain about 1/2 inch up and 1/2 inch down a year from all the compost and mulches I use. But I keep adding grass clippings through the year too, to replace the decomposed ones. I have clay. Heavy clay. It is sandy though. At least in the clay I have, it works beautifully to compost right in the garden. It took about 2 to 3 years to build up a large enough worm population to do it though. The first year I literally had no visible worm population. The soil was so hard I gave up digging and simply started sheet mulching on top of everything. Been doing that every year since.

[nnjjohn]

anybody know what might be a good crop to start from seed or buy to plant this late in the season for some spare room to plant in a few of my beds? Thinking of trying swisschard but never grew them before..they okay next to cucumbers or tomatoes or both? tia, john

[Redbaron]

Originally Posted by nnjjohn

anybody know what might be a good crop to start from seed or buy to plant this late in the season for some spare room to plant in a few of my beds? Thinking of trying swisschard but never grew them before..they okay next to cucumbers or tomatoes or both? tia, john

I am still planting green beans. In a month or so I'll start planting fall crops like various cool weather brassicas. After that is garlic and walking onions which will overwinter. Once the heat breaks there are snap peas, spinach, radish etc... Even sweet corn can be planted this late if you choose an early type. There are lots of things. My climate is a bit different than yours though.