A moisture analyzer can check potting soil quality

Manufacturers and packagers of potting soil should pay close attention to the moisture content of their products as part of good business practices.  If the content is too high customers pay for the weight of excess water.  If it is too low the manufacturer is putting more soil in the package to meet the indicated weight.   A compact moisture analyzer is an ideal tool to spot check the moisture content of potting soil as it passes from the mixing line to the packaging equipment.

Manufacturers generally define the target moisture content for their lines of potting soil. One supplier has a maximum and minimum percent, explaining that it is determined by taking the weight (wet weight) of a known amount of soil then drying it in an oven and weighing it again (dry weight). The dry weight value is divided by the wet weight value to obtain percent moisture. 

Another supplier targets a moisture content of 50 to 55% noting it is a bit higher than most due to the use of composted organics and the objective of having microbial activity survive the packaging process. 

Fast Spot Checks using a Moisture Balance

 A moisture balance such as the Kern MLB-N available from Tovatech is a fast and highly accurate tool for confirming the moisture content of potting soil.  Similar to the example cited above it works on the thermogravimetric process to measure loss of weight on drying but on a much smaller scale.

It consists of a halogen heater mounted on a precision analytical balance.  Testing begins by evenly spreading a small sample of potting soil on a sample plate that has already been tared by the balance.  The sample plate is placed in the sample plate holder of the moisture analyzer, which displays the weight on the LCD.  The lid is closed and the pre-programmed testing cycle begins.

The moisture analyzer will shut off when the drying is complete and the dry weight is stable, or after a specified period of time.  The moisture balance displays the weight loss as a percentage from the starting weight, the drying temperature and the drying time.  Test results can be recorded on a printer or a PC.

Potting soil is one of many thousands of products requiring moisture content control to help insure processibility, usability, shelf life and quality.  In most instances industry standards and government regulations apply to maximum permissible moisture content.  Compact, accurate moisture analyzers such as the Kern MLB-N are valuable tools to support conformance to regulations.  Contact the scientists at Tovatech for help in selecting and using a moisture balance for your quality control procedures.

How do you measure moisture content in your manufacturing operations?  What types of records do you maintain?

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