pH, EC, and runoff: the only three numbers that matter

What each number tells you

• pH controls which nutrients the plant can actually uptake. Too high or too low and locks-out start.
• EC (or PPM) tells you how concentrated your feed is. Too low: hungry. Too high: burn.
• Runoff EC tells you what's *leftover* in the medium after the plant ate. Trending up = you're feeding too much.

1. 1
   Mix your feed

   Adjust to pH and EC targets for the stage you're in.
2. 2
   Water to 10–20% runoff

   You want to flush a small amount out the bottom — not a flood.
3. 3
   Measure runoff pH and EC

   Compare to feed values. The drift tells you what to adjust.
4. 4
   Adjust next feed

   Runoff EC higher than feed → reduce concentration. Runoff EC lower → plant is hungry.