Improve Your Garden Soil With Rock Dust and Chickens.

rock dust mineral analysis

If you have read any article on this site, you would know that we are based in far north Queensland, Australia.

It rains a lot in the wet season; some years, we can get 3.5-4 mtrs of rain over a 3-4 month period. That’s a lot of rain.

The rain is very welcome as it helps cool things down a little, but the humidity still hangs thick in the air.

Sometimes the rain is not so welcome because it will leach minerals out of the soil, making growing vegetables pretty tough. If you garden in the tropics, you need to do something about the leaching.

That is what this post is all about. This post is also a follow-on post from another titled “making organic soil for raised garden beds,” It also involves chickens.

To begin with, we were made aware of the leaching when we undertook a PDC with Geoff Lawton, who himself studied under Bill Mollison.

We like the idea of being third-generation permies, and we wear it like a badge of honor. In that course, the tropical soils were explained in great detail, and the leaching processes at play in the tropics were described thoroughly.

We decided that if we were ever to be successful at becoming self-sufficient, then amending the soil was at the top of the list of skills we needed to learn. It was paramount. There are other skills that are beneficial to a resilient lifestyle when you think about it, and “23 skills for self-sufficient living” is a good start. But I digress.

We chose not to take on this task alone and figured out that we could employ the chickens to help with some pretty technical aspects of the re-mineralization process.

They never complained about the monumental task they had been given and took to the challenge with great enthusiasm. Many years later, they still happily work at that challenge every…single…day. We love chickens.

What is this task, you may be asking? How can a simple chook fix a problem as significant as the one they have been lumped with? Well…let’s start with a biology refresher.

Minerals and bacteria.

Every living organism requires nutrients to grow, even bacteria.

If the bacteria is parasitic, it will harvest the required nutrients and minerals from the infected host.

Beneficial bacteria build their cellular structures from minerals and nutrients that pass through a life form, be it a human, a fish, or a chicken.

The typical life span of a bacteria is said to average 12 hours, but within a given lifeform, there is a relatively stable population of bacteria. Said another way, for every bacteria that lives, one must die.

The human body holds up to 380 trillion bacteria in our bodies…. significant number, right? It is called the microbiome, and that should ring a bell if you are into eating healthy. When these bacteria die, they have to go somewhere.

It is why we all poop. A large percentage of poo is dead bacteria. It is through this mechanism that farm animal manures are used so much as garden fertilizer.

But what if you could custom design the poo to suit your needs in the garden? This process is something we do, as you will discover below. However, this method is also used in “how to maintain organic soil for raised garden beds.” We swear by this method.

Chickens don’t eat off plates.

The subheading above tells it how it is in the real world.

Chickens will walk through their food, scratch it, and flick it all over the place. They don’t seem to care that the food is covered and mixed with dirt, and it is almost as if this is by design.

Eating the dirty food helps a few processes that the chickens use to access seeds and harder foods because chickens have a crop where they grind the hard foods and break them down to make digestion easier.

They need to replace the grit regularly, so they happily swallow more grit to serve this purpose, so the food in the dirt helps to replace the grit in the crop that makes its way through the bird.

It is a simple process that is fascinating in itself. Observing the chickens and a few hints dropped during a part of the PDC gave us the inspiration to investigate further.

Cows and biodigesters.

Ok…. sounds off-topic but stay with me here.

Let’s look at why cow manure is used so much in the garden as fertilizer. Grass is made of components like minerals and nutrients, just as we are.

It also hosts many bacteria on the leaf/blade surface, and these bacteria have a life cycle like any other bacteria.

These minute lifeforms hold nutrients and minerals that make up their bodies. Along comes a cow and eats them.

They take a wild ride through the cow’s stomachs, and that’s four by my book.

The cow takes any nutrients it needs and poops out the rest, along with the dead bacteria from the cows’ bodily functions.

Those dead bacteria, i.e., the minerals and trace elements that made up the bodies of these microbes, are now plant available. Do you see the pathway from dirt into plant-available minerals?

It is the same with the chicken.

It is this process of minerals passing through the gut of an animal that converts the minerals and trace elements into plant-available forms, and that is why we all use animal manure in our gardens.

Custom-designed poo.

Some plants require certain minerals and trace elements more than others. We humans have become accustomed to heading off to the local hardware or garden center and buying purpose-specific fertilizers.

You can get rose fertilizer, citrus fertilizer, lawn fertilizer etc.

The chemists who manufacture these fertilizers are aware of the individual plant requirements, so they custom brew their product and proceed to sell it to the gardener.

It can become expensive to stock your shed with every fertilizer that you could need, so it makes sense, both financially and logically, to make your own.

The thing to recognize here is that the plants and vegetables all grew pretty well before the advent of manufactured fertilizers. It is only through clever marketing and straight-up convenience that the fertilizer industry has become so large.

Suppose there was a way to make a fertilizer that filled the needs of all garden plants. Would you be interested in how that could be done?

To get to that part, we have to set off on a quick trip about 4 hrs drive south of where we live.

The curious cow farmer.

I came across some information about a farmer who noticed a patch of ground where the cattle were regularly hanging, and he saw the feed that the cattle were feeding on was far more vibrant than most of the rest of the property.

Being a typical observant cattleman and curious to boot, he had the soil from that area analyzed. The results showed that the ground in that patch was very heavily mineralized.

He explored further and ended up becoming a crusher of rocks as well as a cattleman. A new business was born, and the product to sell was minplus.

I have lost the link to the analysis data sheet, but I remember that the rock dust was made up of 72ish minerals, trace elements, and minor trace elements.

I may be off one or two in number, but it will make no difference.

This dust was the missing ingredient we needed to re-mineralize our soil here at home. The discovery of this product was a massive win for us.

How do we get this dust into a plant available form so we can fast-track everything?

min plus rock dust used as a soil amendment
No connection to this company at all. Just happy to plug a good product.

Chickens eat dirt.

Remember back up this article where we discussed how chickens eat off the ground?

We’re ready to bet that some of that dirt is converted inside the chook, and the minerals are converted to plant available components.

I reckon that’s a pretty safe bet. It seems logical that this process has been going on since the dinosaurs ate everything and starved.

That may not have been the actual reason they all died, but that’s my theory, and I’m sticking to it.

palagonite used as soil conditioner
A similar product we use here as well.

Let’s play chef.

Every morning we feed the chickens at about 6.30. They meet us at the gate without fail and are only interested in one thing. Breakfast.

They crowd us while we put their feed in the bowl and the hanging bird feeder, and we sit back and watch them voraciously attack their meal without a word or action of acknowledgment.

Over time we have come to understand that we are not likely to receive any recognition, so we just put up with their behavior.

Maybe the next lot of chooks will be different, we tell ourselves.

We don’t mind. We have an understanding…the chooks and us. If we give them what they want for breakfast, they will continue converting that rock dust into plant-available elements.

Yes, we feed the chickens rock dust.

And if you have read this far you will understand exactly why.

We have developed a few enhancements to this process that fit our climate and site situation, but that is for another post because it goes into the different types of soil that tend to be bacterial or fungal.

This can make the difference between having a good harvest or the opposite. For now, let’s continue with the chicken’s breakfast and how we get protein into their diets.

Plants and protein.

We are fortunate to have the ability to grow profuse amounts of a plant called Katuk, or sweetleaf, as it is known in some places.

It is very high in plant-based protein and minerals. Every time we feed the chickens, we give them a generous handful of these leaves that we stir through the chicken feed.

This stirring coats the leaves with a fine layer of rock dust, and the birds love it.

If you think about the science behind the process, we are giving them almost a complete diet just with the leaves and rock dust.

We don’t just give them that, though. We bulk out the meal with a small scoop of fermented mixed grain and a few spoonfuls of cooked rice.

This is the deal with the chooks; they demand this for each meal, morning and evening, and in return, they will create the best designer poo ever known.

sweetleaf plant grown for fish food.
Katuk in our garden. One of a few thousand plants. Self replicating chicken feed.

Closing the circle.

We do our best to live within our means, and if the income meets the outgoing, it is balanced.

We save a little for a rainy day, but it is balanced or moving forward. We treat the yard in the same way, with the moving forward part being improving soil fertility.

At the start of this post, we mentioned the problem of leaching that tropical soils suffer from.

We are now reversing this process with the willing help from the chickens. Every winter is our vegetable growing season. The sun is to our north, and the temperature is relatively mild by our standards.

We have the opportunity to grow tomatoes, kale, cabbage, celery, radish, and many other varieties that people who live further from the equator take for granted.

It is through the joint effort of the chickens and us that we can heavily plant raised garden beds with multiple varieties and not apply any external store-bought fertilizers at all.

Depending on how mild the winter weather is, we will have either a short or extended growing time.

We don’t get to choose, but we need to be prepared for it, and having the soil from the chicken pen available all the time allows us to be ready for the coming season. Thanks to science and the chickens.

This process is the primary foundation we depend on to allow us to be self-sufficient in garden greens, seasonal vegetables, most root crops, and most fruit.

We can also say that we are self-sufficient in ginger and turmeric by using this poo in the garden where we plant them. We have a post titled “can ginger and turmeric be grown together?” that details how we go about it.

We plan to grow more than we need each season, so we have enough to preserve and store for extended shelf life. This is working well so far, and we are confident about the future because of what this article describes.

Soil fertility is money in the bank.

Seasonal impacts.

As we mentioned at the start we have a defined wet season.

This leaches the minerals from the top levels of the soil where annuals and small perennial roots are located, which is a constant.

The leaching is not just in the soils of the garden, though.

Remember that the chicken’s pen floor is dirt (although it is often covered with straw or sawdust/wood shavings to help bring insect life to the surface), and it is this that zone is also subject to the leaching, albeit very much slower than the rest of the yard.

To bypass this leaching, we collect the chicken droppings from the roosting hut, which is bagged during the wet season and spread over the raised garden beds at the beginning of the winter growing season.

This bypasses any leaching issues because the bagged poo has never met with the torrential tropical rains, and so it still holds all of its plant available components in readiness to be fed to the plants.

The circle is completed at the season’s end when the caterpillars and other insects move in at the change of the temperatures, and it gets too hot for the softer plants. The chickens then dine on pulled-out kale, cabbage, bok choy, radish leaves, and many other types of veg.

The process starts all over again with the chickens eating in the dirt.

We love the scientific simplicity of it all. We hope you do too. It is valuable knowledge that can set a solid foundation to expand your growth potential.

To help with some perspective on how this information can help with certain plants, “how to care for turmeric plants“, and “growing common ginger root” are posts we recommend reading.


There is an important distinction that needs referencing. This article discusses how we obtain plant-available fertilizer from the chicken roost.

The fertilizer is spread to raised garden beds that have been topped up with soil taken from inside the chicken pen. The article title is “making organic soil for raised garden beds.” The garden beds are then covered with organic sugarcane mulch that we buy.

Article by Tim Blanch for He is a qualified Permaculture designer.