rock piles

I'm wondering if some people would weigh in with there experience or opinions of growing in rock piles or with rock mulch.

I seem to remember Bills herb spiral incorporating height gained by stacking rocks and sticking sandy soil and rosemary on its top.

Would rocks thermal mass make the root zone warmer? Would it take longer to warm up in the summer? Would it make the ground colder in winter? What about in greenhouses?

It seems to me that the relative stability of soil temperature and the large mass of rocks would cause minimal effects during the cold season and would gain you several degrees with lasting overnight effects. Could be all sorts of useful for pushing climate zones. Subsoil irrigation would be idea of course, or spot watering.

You mean like Phoenix? Las Vegas? Places where entire yards are covered with rocks with a tree here and a cactus there?

In those places, it doesn't make the root zone warmer, it keeps soil moisture from evaporating and keeps the root zone cooler. You pick up a good size rock, and the dirt beneath it is damp from the last watering.

Rocks do have a tremendous heat capacity, so down a few inches, the soil temperature is very moderated. (You would know this if you were a desert tortoise or you had one as a pet).

There is also the factor of rock color to keep in mind. A very light, almost white granite boulder is not going to get as hot as a piece of black lava rock. You can soak up a LOT of heat for the greenhouse if the sun is shining through onto some black lava rock.

What specifically do you want to do?

Thanks John. Mostly I'm just trying to strike up interesting conversation and figure it out as I go along.

Taking over the world with sticks and stones and words would be epic fun too.

I've heard that rock piles next to trees help regulate the soil temp and also provide habitat for insect eating lizards.

John Elliott wrote:You mean like Phoenix? Las Vegas? Places where entire yards are covered with rocks with a tree here and a cactus there?

In those places, it doesn't make the root zone warmer, it keeps soil moisture from evaporating and keeps the root zone cooler. You pick up a good size rock, and the dirt beneath it is damp from the last watering.

Rocks do have a tremendous heat capacity, so down a few inches, the soil temperature is very moderated. (You would know this if you were a desert tortoise or you had one as a pet).

There is also the factor of rock color to keep in mind. A very light, almost white granite boulder is not going to get as hot as a piece of black lava rock. You can soak up a LOT of heat for the greenhouse if the sun is shining through onto some black lava rock.

What specifically do you want to do?

What about in temperate climates, like New England? We have rocks, of a quantity and magnitude that is hard to impart via computer. Primarily gray granite. We are interested in developing some Mediterranean-style gardens in a south-facing area above a natural pool and I am planning on incorporating some half-buried boulders into the design to act as passive-solar heaters for the ground around fig, olive, and pomegranate trees. Have never done this, have no idea if it will work, would love to hear of anyone in the 6b/7a region doing anything like this.

I'm on lower Vancouver Island where we tend to get wet winters, slow springs, a cold June (just as your trying to get your seedlings to grow faster than the slugs) and a *very* dry summer. It seems as if rocks should be a good solution, but I have two thornless blackberries and the one planted behind the kiwi trellis gives me berries in July, but the one against a low rock wall forms berries, but they never seem to ripen. I would have thought that both plants would be starting out with the same amount of moisture. The one near the kiwi is protected from the deer, but the other hasn't been badly chewed. Quite frankly, neither are as happy as I'd like, but I just don't do the "water every 2 days" thing that is SOP in this region. Possibly the issue isn't the rocks, but the soil. In front of the "wall blackberry" there's a Honeyberry bush that also hasn't been particularly happy. I read recently that they don't like the heat. I also got a good price on 4 more, and planted them up by the kiwi so now I've got a double study going on there! The "Kiwi Honeyberries" looked really happy until things got a little hot and dry and I thought I'd lost them. Last I checked at least 3 had signs of life, so I will just have to wait until next spring to see what's happening.

The downsides of rocks here is they tend to protect the Himalayan Blackberry roots, and they can take over faster than I can out-compete them.