Rocks in the garden

I have literally tons of rocks in my garden.  I'm digging them out to replace with hugelkultur beds.  I'm piling the excavated rocks on the downhill side of the garden.  What are some ideas of how I can use these rocks in the most beneficial way for my garden in a usually dry, sometimes flooding, hot in the summer, usually mild winter, climate?  Can rocks mitigate temperature extremes - that is, can they keep it from getting as hot as well as cold?

Interested in your ideas for using many many rocks in and around the garden! 

I've heard rocks are used as mulch in arid climates where lots of organic matter is hard to come by. The heat retention of a large rock also allows you to grow things 1 or 2 zones higher than yours.

Thank you.  I guess what I'm wondering is, do the rocks help moderate the temperatures in the other direction as well, that is, if it doesn't get as cold, will it also not get as hot?  Because I generally have more than enough heat here! 

i use all the rocks i dig up for terraces, raised beds and borders.

Thanks.  Seems like they would store cold too, like marble. 

they do and depending on the rock they can store some moisture too. our forest gardens terraces are rock and designed to hold heat in the winter and cool in the summer.

Thank you.  That makes more sense to me than them only holding heat.  Not that I understand physics at all! 

in arid places, folks sometimes plant trees in pits with rocks in the bottom.  the rocks stay cool in the shade of the pit and water condenses on the cool surface and drips down to the tree roots.  if you're not in such an extreme place, the shady side of any pile of rocks ought to do the same thing.

Thermal masses, like rocks, simply slow down any temperature change: they generally heat up slower and cool down slower than the surrounding area. Your garden will heat up as the sun hits it, reaching its hottest temperature some time in the late afternoon and then cool down at night hitting a low around sunrise. The rocks would make their area heat up slower over the day and cool down slower at night, bringing the maximum and minimum temperatures closer together.

Note that this is further complicated by wind, vegetation and the rate of heating/cooling of the surrounding soil.

The other advantage of a rock pile is its use as beneficial wildlife habitat for lizards, toads, snakes, predatory insects, etc. If you have access to Edible Forest Gardens volume 2, the appendix lists over 100 beneficial species with their habitat requirements.

joshthewhistler wrote:
Thermal masses, like rocks, simply slow down any temperature change ...

Note that this is further complicated by wind, vegetation and the rate of heating/cooling of the surrounding soil.

Also more complicated due to shadows, and interacts with slope and aspect of the site. But can be used to create areas that are protected from the heat of the mid-day sun.  Cacti on the exposed side, tender plants on the protected side.

joshthewhistler wrote:
The rocks would make their area heat up slower over the day and cool down slower at night, bringing the maximum and minimum temperatures closer together.

That's exactly what I would like to achieve! 

Ladies and gentlemen ...

The mighty ... the glorious .... the amazing .... Sepp Holzer of Austria.

Thank you!  Sepp is my new hero, even though our climates could hardly be more different. 

I think this is the video about rocks:  http://www.youtube.com/watch?v=F4LPTcP_EHU&feature=related

I think Josh is right on with his explanation.

I am exploring the use of large rocks strategically spread throughout the garden to aide in the thawing process in spring. What Josh was explaining is very much the characteristic of rocks/concrete in the warm parts of the year.

Something that I find interesting and that I have been looking at in rock outcroppings and also cemeteries is how the vertical face of a rock, if facing south (northern hemisphere), induces melt faster by providing a dark energy absorbent mass. Once the white of the snow is gone the ground warms much more rapidly than it would have in a flat garden space.

One thing I haven't quite figured out but thought about plenty (and Holzer videos may hint at) is that if it is a large rock and much of it is buried (picture an iceberg, with the majority of the mass underwater) will it act as a geothermal syphon and buffer the temperatures of the earth below and the weather above. So essentially, not only would we be getting energy from the sun and storage from the rock, but we would also be pulling energy up in the cold and pushing it down in the warm parts of the year with the rock acting as a conduit.

Additionally, rocks and gravel are the primary source of minerals in the soil and break down as your plants need them.

I am sure this is more than Ludi wanted, but I am curious to hear other people's thoughts about what I have been wondering about for a while now.

-Troy
http://pittsburghpermaculture.org

I have used large flat stone in my garden beds, they work like mulch, channel rain water and act as a thermal mass.  I plant seedlings in the interstices and don't have to worry about weeds taking over as much.  Also, after a year or so in the same place, you can pull them up and put them someplace else, what you have left is a beautiful bare spot ready for planting, fertilized because worms have been pushing up casings (they seem to like rocks too).

Troy wrote:Additionally, rocks and gravel are the primary source of minerals in the soil and break down as your plants need them.

I am sure this is more than Ludi wanted, but I am curious to hear other people's thoughts about what I have been wondering about for a while now.

-Troy
http://pittsburghpermaculture.org

Troy, I was going to mention this as well. I've noticed when digging up plants and watching trees roots as I'm digging that they actually *like* to wrap their roots around rocks and crack them. Now that I understand the role of soil microbes and mycorrhizae, I think there's a very good reason for this. We have nothing to fear from rocks. They become soil.

Ludi Ludi wrote:
I have literally tons of rocks in my garden.  I'm digging them out to replace with hugelkultur beds.  I'm piling the excavated rocks on the downhill side of the garden.  What are some ideas of how I can use these rocks in the most beneficial way for my garden in a usually dry, sometimes flooding, hot in the summer, usually mild winter, climate?  Can rocks mitigate temperature extremes - that is, can they keep it from getting as hot as well as cold?

Interested in your ideas for using many many rocks in and around the garden!   

Use them to stabilize slopes, grow certain herbs like lavender, rosemary, and thyme which seem to thrive in rocky ground, modulate temperatures, etc. Sepp Holzer is a genius with this.

We used the rocks on site to build our house and now we're terracing and making little warm areas either to sit in or for tender plants. It's amazing how comfortable they are to sit next to in the evenings.