Keep in mind that some soil naturally looks lighter, despite the amount of moisture in it. Familiarize yourself with how your specific type of soil typically looks before you assume that it’s dry.
You can expect to pay $10-20 USD for a moisture probe that has a traditional scale indicator and few other capabilities. If you want a traditional probe or meter that has multiple capabilities, it’ll likely cost you closer to $50 USD. Digital probes and meters with few capabilities can cost as little as $30-40 USD, while more advanced ones that can determine other measurements can cost $50-200 USD or more. Some other capabilities that soil moisture probes and meters often have include measuring the pH value of the soil and determining soil temperature.
If you’re hoping to get an accurate idea of how much moisture there is in the soil that makes up a large area, take a few more readings in different spots that are spread out within the area. In the very least, test your soil any time it looks and feels very dry or very wet. This way, you can find out the exact moisture level and water or irrigate your soil accordingly.
A smaller weight difference indicates dry soil while a larger weight difference indicates moist soil. Different types of soil can survive on different amounts of water. However, the ideal balance for most soil types is 50% solids, 25% water, and 25% air. [10] X Research source To calculate the exact amount of water that makes up the soil sample, subtract the dry weight of the soil from the wet weight of the soil (in grams). Then, divide this total by the dry weight of the soil and multiply this total by 100. For example, if the sample weighs 6 oz (170g) when wet and 5 oz (140g) when dry, then your sample is made up of 21. 4% water.
The price range for tensiometers is typically between about $70 USD and $200 USD. If your tensiometer determines that the water tension in the soil is 10 centibars or lower, there is an excessive amount of moisture in the soil and you may need to irrigate. If your tensiometer determines that the water tension in the soil is between 60 and 80 centibars, your soil is likely too dry and needs to be watered. [12] X Research source
