More Good News About Dirt
So the next section in the Arizona Master Gardner manual is all about caliche, the local name for the limestone that’s so common here, just below the surface. Caliche is probably the reason that the southern two-thirds of my house is 10″ higher than the northern third. The little steps in two doorways makes it seem like I have a sunken living room, and that’s an interesting minor architectural feature of the house. But I’m pretty sure that the drop-off there is a result of the fact that the builder didn’t want to have to blast out a bunch of rock on the south end (or truck in enough concrete to support the north end).
But the fact that the drainage test went so well indicates that, while there may be caliche nearby (under the house), it isn’t a problem around the garden site.
Next, there’s a section about soil depth and surface features. I already know I’ve got at least a foot and maybe two (that’s what I’m expecting to have to dig up) in depth before I hit rock. It also seems fairly clear (and typical for the Sonoran Desert) that there’s not much organic material in this dirt and it’s fairly difficult to dig around in.
Now there’s a section on soil components and the 18 elements plants need to live. Finally, there’s a section about pH. Here’s an interesting illustration of nutrient uptake relative to soil pH:
The manual (and the illustration) says that nutrient uptake is good at around 6.5 to 7 pH, and then it says that soil in Arizona is usually around 7 to 8.5 pH, or a little more alkaline than we’d like. Then they recommend having the soil professionally assayed for actual nutrient content.
OK, maybe later.
And why oh why haven’t I started a compost bin yet? Darn, I could have been doing that all this time. I think I haven’t because I hadn’t chosen a good spot yet. Now I have, so there’s something to get started on this week.
While I’m doing that, here’s a blooming barrel for you to look at.