Adequate moisture is critical for growing plants successfully. For most plants, too much water is more dangerous than not enough. The key is to learn how to gauge soil moisture effectively and to water plants only when they need it, not on a set schedule.
Checking Plant Moisture
When it comes to testing moisture in plants, the feel of the soil is the best guide. As a general rule, a potted plant in a container measuring 6 inches (15 cm.) in diameter needs water when the top 2 inches (5 cm.) of soil feels dry to the touch. A larger container measuring 8 to 10 inches (20-25 cm.) in diameter is ready for water when the top ½ to 1 inch (1.25-2.5 cm.) of soil feels dry. Insert a trowel into the soil, then tilt the trowel to check the moisture of garden plants. You can also insert a wooden dowel into the soil to determine the depth of soil moisture. If the dowel comes out clean, the soil is dry. Damp soil will cling to the dowel. In most cases, the soil should be damp to the root zone, 6 to 12 inches (15-30 cm.). However, sandy soil drains quickly and should be watered when the soil is dry to a depth of 2 to 4 inches (5-10 cm.). Remember that the need for water also varies widely depending on the plant. For example, mostsucculents require dry soil and infrequent watering while some plants, such as columbine, prefer consistently moist soil. However, nearly all plants require air circulation around the roots and are prone to rot in poorly drained, waterlogged soil.
Soil moisture monitoring can also be achieved with specific tools. A variety of simple, inexpensive soil moisture meters are available in garden centers and nurseries, and many are suitable for both indoor and outdoor growing. The meters, which tell you if the soil is wet, moist, or dry at the root level, are especially effective for large potted plants. Other soil moisture monitoring tools, often used for agricultural applications, include tensiometers and electrical resistance blocks, which indicate the moisture tension of the soil. Although both are accurate and easy to operate, they are more expensive than simple probes. Time Domain Reflectometry (TDR) is a newer, more expensive method that measures soil moisture quickly and accurately. However, the sensor often requires recalibration and the data tends to be relatively difficult to interpret.
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FAQs
A moisture meter is a small hygrometer that measures how much moisture is present in soil. Moisture meters are easy to use and usually have one or two metal probes that are pushed down into the soil to provide a reading.
How do you measure the moisture content of soil? ›
Calculate the moisture content of the soil by subtracting the weight of the dry soil from the weight of the moist soil, and then dividing by the weight of the dry soil.
How to measure moisture content in plants? ›
The Best Way to Get Accurate Moisture Content Measurements
- Hand Tests. A method whereby the farmer checks the moisture of a plant, such as hops or hay, by their look and feel.
- Oven-Dry Tests. This method uses ovens, dehydrators, or even microwaves to dry out a sample of material. ...
- Moisture Meter Tests.
Impact Of Soil Moisture On Plant Growth
The optimal range of soil moisture content for crops depends on the specific plant species, but the range for most crops is between 20% and 60%.
How do you gauge soil moisture? ›
Dry the soil out in the oven by setting it to 221 °F (105 °C) for 24 hours. Then, weigh the sample again. The difference in the weight before and after drying the soil in the oven will reveal how much moisture is in the soil.
What is the method for estimating soil moisture? ›
Gravimetric method or drying method is a direct method of determining the moisture content by drying the soil sample and measuring the difference between the wet and dry sample weight. This method is precise and reliable, while recommended mostly for experimental work.
How do you calculate the percentage of soil moisture? ›
Now, apply the formula: Soil Moisture Percentage (%) = [(Wet Soil Weight – Dry Soil Weight) / Dry Soil Weight] × 100.
What is the best moisture meter for plants? ›
The best plant moisture meter is an inexpensive tool that can help establish and maintain plant health. Our top pick, the Xlux Soil Moisture Meter, is simple to use and quickly makes you a better plant parent.
What is the direct method of soil moisture measurement? ›
Gravimetric Methods: In this method soil moisture is determined directly. It involves removing water from a soil sample by evaporation, leaching or chemical reaction. Soil moisture content is calculated from the mass of water removed and the mass of dry soil. They are simple and inexpensive, hence widely used.
What percentage of moisture should plant soil be? ›
Recommended Soil Moisture Levels
It is important to note that the majority of flowers, trees, and shrubs require moisture levels between 21% - 40%, while all vegetables require soil moisture between 41% and 80%. NOTE: All vegetables require soil moisture between 41% - 80%.
The amount of water is determined by subtracting the dry weight from the initial weight, and the moisture content is then calculated as the amount of water divided by the dry weight or total weight, depending on the reporting method. Even this simple loss-on-drying method is mined with potential variability traps.
Where can I find soil moisture data? ›
These data sets are also available on Google Earth Engine (GEE) data catalog, enables users to acquire, process, analyze and visualize soil moisture data rapidly for any user specified region without downloading and processing a large volume of data on the user's desktop.
What is the most accurate way to measure soil moisture? ›
The preferred method for determining soil moisture is the use of gravimetric soil moisture. However, if a person has experience in the hand-feel method and is comfortable in this method, this is an acceptable method. The use of the hand-feel method and gravimetric soil sampling together is strongly encouraged.
How do you assess soil moisture? ›
This soil moisture data can be either collected through soil moisture sensors installed in the field or estimated through remote sensing or data on other factors. ML algorithms are used for predicting soil moisture from various available datasets, which can further assist in irrigation scheduling.
How can you measure moisture content? ›
The amount of water is determined by subtracting the dry weight from the initial weight, and the moisture content is then calculated as the amount of water divided by the dry weight or total weight, depending on the reporting method. Even this simple loss-on-drying method is mined with potential variability traps.
How is soil moisture detected? ›
Soil moisture sensors measure or estimate the amount of water in the soil. These sensors can be stationary or portables such as handheld probes. Stationary sensors are placed at the predetermined locations and depths in the field, whereas portable soil moisture probes can measure soil moisture at several locations.
How do you test the optimum moisture content of soil? ›
The compacted soil specimen should be removed from the mold and placed onto the mixing tray. The water content (w) of a representative sample of the specimen should be determined. The remaining soil specimen should be broken up, rubbed through 19 mm IS Sieve, and then mixed with the remaining original sample.
