What is an EC Pen and how do I use one?

What is an EC Pen?

You can use an EC pen (Electrical Conductivity pen) to measure the concentration of dissolved nutrients in your farmstand tank.

EC pens measure how well a solution conducts electricity. Pure water doesn't conduct electricity well, but dissolved mineral salts (like those in your nutrients) increase conductivity. The more nutrients dissolved, the higher the EC reading.

If you are following weekly nutrient dosing instructions regularly for your Farmstand or Nook, you do not need an EC pen. But if your dosing schedule is more irregular, or if you want to check that your plants receive the most ideal amount of nutrients for your growing environment, an EC pen is a great option. We recommend the EC pen from Bluelab.

How do I use an EC Pen with my Farmstand?

Fill your Farmstand tank with water and add the recommended amount of nutrients as normal. Run your pump for 5 minutes to ensure the nutrients are well mixed in the tank.

Use your EC pen to take a conductivity reading for the water in your tank. Use the charts below to determine if any dosing adjustments are needed.

Original Farmstand

Nook Farmstand

Using a Flow Meter

If you have a flow meter on your hose—or some other way to determine exactly how much water you will add to your farmstand—you can dial in your nutrient dosing as follows.

Check the EC in your tank before adding a new water.