To ensure that your plants are being fed the proper nutrients and nutrient concentrations, it is important to monitor your nutrient solution.
On a daily basis you should test the nutrient solution and record the results
- EC (Nutrient concentrations)
- PH (acidity / alkalinity...see Lesson 4 for more information on PH)
- Temperature of nutrient solution
- Daytime room temperature
- Nighttime room temperature
It is also important to record when you replace your nutrient solution so you can easily determine when it should again be replaced.
In addition to these tests, you may also want to record the stage of plant growth, the size of your plants and any problems or significant changes.
Recording this information gives you an accurate accounting of what is happening with your plants. This data is an excellent tool for diagnosing problems, should they arise.
Advanced Nutrient Testing
Neither an EC or TDS meter can indicate precisely what nutrients make up the fertilizer solution. More complete test kits are available for this purpose. Many commercial growers test their nutrient solutions on a regular basis to ensure they are feeding exactly the mix that is intended. Regular leaf analysis is an excellent tool for determining the health of your plants. Leaf tissue samples are dried, crushed and analyzed to determine the exact nutrient content.
Most of the more complex kits will test nitrogen, potassium, phosphorous and sulfur. Commercial labs offer more precise results. In the event of a combination of nutrient deficiencies, the symptoms of one problem may mask the symptoms of another. A leaf tissue analysis may be the only way to determine what is wrong with your plants.
Listed below are some testing devices to get started with.