The attached URL shows a product that I am sure you didn't have in mind.

I'm sure you're looking for one of those little battery-electronic gadgets with the arrow that goes from dry to moist. This product ain't that.

This is the kind of probe that one should use in the garden. Read the details.

Aside from this, your finger and maybe a small trowel work better than those little electronic gadgets.

Joe

Here is a link that might be useful: Soil Probe

I have a probe similar to the one in the link but I never use it for native plants which do not get summer water ever. Calif ornia natives are used to wet winters and dry summers and summer water will kill some of them. There is no place on my uncultivated property without summer water that I would be able to probe with any moisture meter without drilling a hole first. Al

I found a site that said you can make basically the same thing by using rebar with a handle welded to the top (if you have a welderperson handy, anyway).

Brenda

Thanks for the responses. One irony in my question is that my spouse has spent his career specializing in the modeling & measurement of water flow in unsaturated soils. But though that makes for great discussions on the topic, research methods don't translate into practical home garden use!

I wasn't originally thinking of a soil core sampler, but that is a possibility & the unit suggested looks heavy duty.

Or, as both Brenda's & Al's comment suggest, I can keep using the cheap & inexact soil moisture gizmos, using a sturdier auxilliary rod to punch a new hole each time before inserting the fragile probe.

No water in summer is true for a lot of established California natives in our area -- certainly most of those we've chosen for our suburban garden over the years. But we've also learned that we need to pay attention &, in some cases, do some limited watering at least through the first summer in the yard.

Thanks for the feedback!
Elsa

I recently came across a company called Vegetronix which sells durable soil moisture probes. They are also very inexpensive in the 20-30 dollar range. They also sell direct to gardeners.

Here's a link:

http://www.vegetronix.com/Soil-Moisture-Probe.phtml

Here is a link that might be useful: Soil Moisture probe

I found a soil probe specifically made for container plants at
coastlivetropicals.com

heres a great probe I found and bought one a while back, its an extremely versatile and valuable gardening tool. well worth the $

http://www.amazon.com/Alien-Soil-Probe-Container-Interior/dp/B00MHN14O4/ref=sr_1_1?ie=UTF8&qid=1438842155&sr=8-1&keywords=soil+probe+interior