Testing soil moisture is not an exact science but a soil moisture sensor kit makes it much more accurate. This video does not specifically mention a soil moisture gauge but gives an interesting and easy to understand explanation of how plants draw water up through their leaves. After watching this video check out a soil moisture meter demonstration.
Soil Moister Gauge Plant Watering Tutorial
Hey everyone! Today on the Techno Gardener we are going to explain the basic concepts behind soil moisture and how it applies to your plants. Plants are able to obtain water through a process known as capillary action. This is water’s natural ability to adhere to surfaces and flow against the force of gravity. Water will cling to other surfaces and actually pull itself up as seen by the meniscus.
In many containers the narrower the container the higher water will pull itself up. In the case of plants the water is pulled out of the soil with the roots using capillary action similar to how the paper towel is pulling the water from one glass to the other. After a watering period soil is not able to retain all of the water due to gravity. This water will run out immediately after saturating the soil. This is known as gravitational water.
You will notice that there reaches a point when the water stops draining from the sponge. This is known as water holding capacity. Defined as the water content of a soil after the excess gravitational water has drained out because of capillary action. Water is able to adhere more easily to soils that have greater surface area.
Because sand is made up of relatively large particles it has much less surface area than its clay counterpart and it can’t hold as much water thus having a smaller water holding capacity. However, in most cases soil is not entirely just sand or clay but rather a mixture of sand clay and silt known as loam. The amount of water that a plant can extract from a soil is known as plant-available water.
Imagine the sponge itself as the soil and the hand squeezing as the plant extracting water. For use initially when squeezing water comes out easily but the more that is extracted the harder you have to squeeze. There comes a point when the plant can no longer extract water from the soil to sustain life. This is referred to as the wilting point. Even though there may be water in the soil it is too hard for the plant to extract. In the case of the sponge, although there still is moisture inside the sponge no amount of squeezing you’ll be able to get that remaining moisture out. Hey thanks for watching.
Our Summary: What a great explanation about how plants draw water up from the soil. It also explains why different soils have a different effect on plants. Most succulent plants can live in a wide variety of soils. Almost universally, however, succulents do better in well-draining soil. Their roots do not need to be saturated in water since the succulent itself can store water for drier periods.
Since it is so difficult to know exactly when to water a succulent we recommend you purchase a soil moisture meter. A soil moisture probe will tell you instantly if your potted or outdoor succulent needs water or if it would be better to wait.