How to Prevent Nutrient Burn During Feeding

Prevent nutrient burn by keeping the salt strength of every feed inside the range your plants can use. Mix at the label rate for the growth stage, measure electrical conductivity (EC) before the solution reaches the root zone, and feed to runoff so excess salts leave the container. Record input EC and runoff EC at each feed. When runoff EC climbs above input EC and leaf tips start to brown, stop feeding and leach the medium with plain water.

What Nutrients Do Cannabis Plants Need at Each Stage?

Prerequisites

  • EC meter and pH meter, both calibrated
  • Clean water with a known starting EC
  • Nutrient schedule for the current growth stage
  • Containers with open drainage holes
  • Log for input and runoff readings

Steps

  1. Fill a mixing container with water and measure the starting EC.
  2. Add one nutrient product at a time at the label rate for the growth stage, stirring between additions.
  3. Measure the EC of the mixed solution.
  4. Dilute with plain water when the reading sits above the target range for the stage.
  5. Adjust pH to the range for your growing medium.
  6. Pour the solution over the medium until it drains from the container holes.
  7. Collect the first runoff and measure its EC.
  8. Log input EC, runoff EC, and pH beside the feed date.
  9. Let the medium dry to its target moisture before the next feed.
  10. Leach with plain pH-adjusted water when runoff EC rises above input EC and leaf tips show burn.

Signs to Watch

Brown leaf tips, curled leaf edges, and a runoff EC above input EC point to salt stress. Catch these signs at the first feed after they appear. Skip the next nutrient mix, water to runoff with pH-adjusted water, and resume at a lower EC once new growth looks flat and green.

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Feeding Habits That Hold EC in Range

  • Mix each reservoir at the target EC for the stage, not at the maximum label rate.
  • Water to runoff at each feed instead of giving small sips.
  • Test runoff EC after every feed and write it down.
  • Reduce feed strength when light, temperature, or root health limits uptake.
  • Leach the medium on a set schedule, not only after burn appears.