Question about EC

From a fellow grower: Please explain what EC is assume volume as PPM increases. Seems no difference in dilution. Want to know is what EC is in the fertilizer regimen for flower phase

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Here’s a chart for quick reference of the different ec range per stage of growth.

As a comparison. This chart shows the relationship between the different scales.


Hope this helps clear things up a bit for you.

Edit : Fixed the title too. :wink:


Truthfully, that schedule is the most confusing EC / PPM comparison chart I’ve seen. The values are wack and don’t convert.
As far as I know Hanna is 500 scale. How does an EC value of 1.0 become 800??? Or week 8 flower EC of 2.3 has a ppm of 400.

This schedule makes more sense. EC only gets one decimal

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To add to the confusion, different sources have different recommendations. And it seems each nutrient line has its own recommendations. This is from cocoforcannabis

General EC Ranges for Cannabis in Coco

Just as the nutrition needs of a plant change during its life cycle, its optimal EC range also changes: starting low, reaching a peak during late bloom, and going down sharply at the end. In the chart below, you can find general guidelines for optimal EC at different life stages, however, there are differences between different nutrient lines. Therefore, you should start with the recommendations from your supplier. However, if the supplier recommends EC ranges that are significantly higher than these general EC ranges, I would recommend finding a different supplier. In particular, you should avoid nutrient lines that recommend high EC ranges and frequent flushing.

Seedling Early Veg Late Veg Early Bloom Late Bloom Ripen Flush
400 – 500* 1100 – 1400 1200 – 1500 1100 – 1400 1300 – 1600 800 - 1100 0 - 200

*EC units are expressed in microsiemens. 400 microsiemens = 0.4 millisiemens