It is important when you live in an arid or semi arid climate to make sure that your soil is getting enough moisture. Soil in more arid climates tends to dry out more quickly and has less average rain fall per year than other climates. Arid climates receive less than 10 inches of rainfall per year, and semi arid climates get between 10 to 20 inches per year. With such small amounts of precipitation, it is a necessity to make sure your plants are getting what they need to survive and stay healthy.
One way to do this is with a soil probe. You could buy one, but it would likely not be long enough for your needs. You could also make one yourself very easily, and by making your own, you have more control over the length of the probe.
Step 1 - Find a Length of Rebar
You will need to find a piece of rebar, at least 6 feet in length. Usually, you can pick up a piece simply by contacting a construction company that works with concrete or a paving company. They always have plenty of rebar on hand. Another possibility is to scrounge for rebar left behind from completed construction projects. The piece you use will need to be pointed at one end to allow it to pierce the ground.
Step 2 - Put a Handle on the Probe
You will need to have a handle on your probe to make it easier to work with. The best way to do this is to take the rebar to a welder or a machine shop. Have them weld the handle on to the flat end of the rebar. Ideally, the handle should sit at the end of the rebar to form a T shape. The handle should be made of heavy duty metal that will not bend under normal pressure, and it should be 1 1/2 to 2 feet in length.
Step 3 - Water Your Plants
Water your plants as you normally would. In arid to semi arid climates, it is best to dig a basin around the bottom of your plants. The basin keeps the water from running off and away from the tree or shrub, giving the plant more time to absorb the moisture. Wait a few hours to make sure the moisture has a chance to sink into the ground.
Step 4 - Use Your Probe
Place the probe over the area you watered. Slowly press the probe's pointed end into the soil. Make sure the probe is straight up and down, and not at an angle. Push the probe into the ground as far as you can. When the probe stops is where the moisture stops. Mark the spot on your probe where it meets the ground. Carefully remove the probe and measure to see how far into the soil it went. For shrubs and bushes, the probe should have reached 3 feet. For trees, the moisture level should reach 6 feet down. Adjust your watering