small stones in the garden

I turn my garden soil by hand with a shovel. I have been hand working the same soil for 7 years now and I notice that there are now much less rocks and stones in soil then there were when I began by virtue of being able to spot them and chuck them to the stone fence row as I work. If I was using a tractor or rototiller I'd never notice the small stuff.

You definitely dont want big stones in the garden.  Anything baseball size and bigger should get evicted but I am wondering what is the harm in leaving the small stuff?  Golf ball size and smaller.  Are nt they a long term source of phosphate and potassium and other trace minerals? Or is the rate they provide micro-nutrients too negligible to worry about?  I add lots of composted barnyard manure every year so the soil is healthy and getting healthier. Every year I see more and more and bigger worms in the soil happily eating last year's residues so I likely have no worries about micro-nutrients either.  Its just every year around this time I wonder the same question. I'll probably keep coming down on the side of tossing the stones and pebbles so root crops can grow without impediment.  

What are your thoughts/practices?

I think stones help to stabilise the soil temperature and create tiny cool reservoirs of damper soil underneath to benefit soil life.

I don't have larger stones, most the size of a quarter or smaller.  I leave them.  I can't see how they hurt anything.  I think the time for them to break down into useful minerals may be measured in eons, but it's less work to leave them and unless you need them for some other purpose, I wouldn't do the extra work of removing them.

We have one bed that has been double dug and the "rocks" were removed as we found them, stones (1" diameter and smaller) remain in this bed.
This is the one bed we use for root vegetables such as carrots and beets, which needed the extra work done so they would grow.
Our other beds (so far total is 7 garden beds) have never been dug, we simply plant, water and mulch. If we find a rock when planting, it is removed but otherwise nothing is done to remove anything but the harvest.

Rocks are only going to give up minerals if bacteria and fungi are present since these are the organisms that can "mine" the minerals from rocks.
If you dig your beds every year, you are disrupting on a yearly basis, disruption tends to kill off bacteria and fungi. Tillage is the surest method to create dirt out of soil.
If you want your plants to be able to access those minerals that are held in the rocks, you need to encourage bacterial growth and fungal growth.

Stones are part of soil structure, they keep soil from compacting, provide air passages to roots, they also provide homes to bacteria and serve as anchor points for fungi and plant roots.
water infiltrates better in soils that contain some stones, those air passages also function as water infiltration highways.
The only time you don't want them is when you are growing delicate root vegetables but even then, small stones are not going to do any harm and will instead do far more good in the presence of a healthy microbiome.

One of the things we do is start a garden bed space as a straw bale garden, the bales are set in place, surrounded with 2x6 or 2x10 to keep the bales tight together and then those bales are inoculated with spent coffee grounds and watered for three weeks.
After that break in period they are planted with started plants.
We can get two years from a set of bales, at which point we can add a second layer of new bales and go through the process again.
At that point, the bed has become a proper raised bed with no stones in the medium since it is all composted straw and soil.
From that point it is just a matter of adding finished compost and compost teas, the soil beneath the bed has loosened and is very rich in microbes and worms.

Redhawk

Anything smaller than a hen's egg I leave in the soil. The reason I opt for that size is that larger rocks get caught in the cultivator blades. I till in compost & soil amendments, as needed, between annual crops. I suspect that the rocks play an important role in my soil type. I live in the tropics, so that may be part of it.

Now, my pastures are heavily rocked and are of course no-till. But it took almost 10 years to bring them up to moderate productivity via top dressed amendments, mulching, and rotational grazing. They still have a long way to go before I'd say they were robust pastures. But one thing I've noticed in my pastures, where there are abundant good sized rocks, there is good drainage. Where the previous owner had removed most of the rocks (to build a stone wall), the area is mucky and boggy after heavy rains, and dry & hard between rain. The grass doesn't grow well in the derocked area.

Speaking as a geologist.

Natural stone - not brick, concrete, cinder blocks, slags - are generally not a problem for plants. Some definitely require them.

I go out to the Ardennes and the Boullonais area on walks and bring back rocks for different purposes.

Slatelike rock is used as a stone mulch and weathers easily into clay.
Limestone and dolomite arer used as a slow weathering source of calcium, iron, magnesium and sometimes manganese.
Glauconitebearing sandstone is used as a """"""""""""""""""""""""" of calcium, sulfate, magnesium, iron, phosfate, .....

All rocks and pebbles are usefull as stone mulch, decorative elements, drainage enhancers, water reserve, shelter for tiny wildlife, etc... Mediteranean herbs benefit from a rock diet and not to rich soil.

Stone mulches slow evaporation, stop competing plants from germinating, dampen the impact of heavy downpoors and hence erosion, etc.....


I also use (bought) pebbles to build up an underground water bearing layer that drains water into a deeper layer.

Of course i intend to go almost completely no till once the manmade 'rocks' in my soil are mostly gone. I have a strong bias against manmade stuf in my soil. Old brick tends to contain old paint (containing lead, copper, and other such niceties).

Thanks everyone for your comments. I will leave the small stuff where it lies.

I generally don't remove any stones smaller than a chicken egg. I pretty much stop whatever I am going to remove stones larger than a softball. I really like my fields that have very few rocks!!!

My herb garden has a ton of small rocks mixed with clay. This can turn very hard when it dries out so I have been adding a bunch of wood chips to the top of this clay rock mix. Later as more of my plants grow I will be chopping and dropping what I can right on the wood chips and probably adding more wood chips and other organic material over time. But I don't plan on removing the rocks - one it would be a big pain but I also figured in the long run the rocks would be beneficial for the reasons others have already mentioned. Most of my property actually as very few to no rocks in it so I have been actively trying to find rocks to build habitat for various critters such as snakes and amphibians!

Suffering goodness, I do what is called minimum tilled farming here since no-till is not possible with our soil type. Even then, minimum till is considered removing rocks over BASKET BALL sized. That is a pretty big rock, but they are so beneficial. Have you ever seen a rock on a hot day, pick it up and the underside is moist. This is what battles drought, something I did not see mentioned her. Now imagine if all the rocks were withdrawn and the soil was sandy, yep prone to drought.

Our planters, disc harrows and the like are designed to bang off rocks this big, and while I understand in a home garden it is not possible to farm in such a way, I hope people look at rocks as I always have, vital to the soil and to preventing drought (or watering requirements).

I am glad to see this post thread about rocky soil.

My husband and I just purchased a 5 acre property in France with very rocky soil. The whole region is rocky, but the land is obviously fertile as lots of crops ( sunflowers, corn, wheat etc) being grown.

We are not going to be moving on the the farm for a few years but want to at least improve/prepare the soil when we spend a few months here now and then. I have planted a grape vine and a few other perennials, shrubs etc, mostly to get a feel for the soil, see how things grow. I am happy to say plant are doing well at this point, so there is something good i the soil . Thatsaid I think I have seen two worms in all my digging!. Just that bit of planting was a lot of work: for every plant we put in the ground we removed an incredible amount of rock--I am surprised to find any soil in between sometimes! I used some of these as mulch but mostly we just removed them to make a pile for possible future use.

I have an area of about 900 m2 for a kitchen garden. It is currently covered in grass and weeds a few trees. Initially I thought of doing a compost/cardboard/mulch treatment, but after reading and listening to all sorts of opinions, and realizing I am not ever likely to be able to get a broad fork or shovel into the soil because of the rocks, that perhaps digging through it once to remove the bigger rocks ONCE and them building up the soil would be a better option.

My husband are also thinking of getting a complete profile of the soil. However this is expensive--the testers come to the property to dig a pit etc etc. Since we are not  that young, we want to get things started up right--we do not want to experiment and tweak too much, but start things up as best we can right from the start. Has anyone ever done this kind of analysis? Did you find it useful?

I would a appreciate more ideas and thoughts. Thanks in advance.

Rebecca Lavallee wrote:My husband and I just purchased a 5 acre property in France with very rocky soil.

Sounds to me like great ground for orchard, vineyard,  or pasture: That way, you can leave the rocks alone, and grow crops where the rocks don''t need to be disturbed after the initial planting.