Soil Moisture System Purpose

[last updated: 2016-08-31]

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Introduction/background/purpose:

I planted some trees. Where I live, here in The Dalles, OR, it gets hot. Reminds me a lot of Phoenix, AZ, where I lived for awhile.

I planted the trees in the fall, the first year I was here (2015). The next spring they leafed out well and looked great. But then in early June we had a week of very hot weather, like peak about 105, the rest of the week high 90's. It appears I under-estimated their water needs, when their root ball hadn't spread out and grown in yet.

I have since increased water regimen, doing twice a day when it's in the 90's, but there was some heat damage.

I was especially concerned about damage to the white dogwood. It's planted in the shade of two large junipers, but suffered significant upper-branch leaf loss, and lots of leaf tips burned.
As of now, after about a month since upping the watering, she seems to be recovering. There are a few tiny leaf starts. They aren't growing very fast at all (maybe 1/64" /wk) but they are hanging in there.

Goal:
I want to be able to optimize her watering to get moisture down as deep as possible, out to the extents of the leaf drip-line, to encourage/facilitate deep root growth. This requires some way to monitor the soil moisture content 24 " deep.
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