Nutrient burn is fixed by stopping all fertilizer and flushing the root zone with pH-balanced water until runoff EC or PPM falls back into range. Once readings normalize, resume feeding at half the previous strength. Leaves that already show damage will not heal. Judge your recovery by the new growth that appears over the next 7 to 14 days.
Cannabis Nutrient Burn Prevention Guide
Signs You Have Nutrient Burn
Nutrient burn shows up as burnt, crispy tips that progress inward along the leaf edge. Affected leaves often turn dark green before the tips brown, and they may curl upward or hook downward. Because salts concentrate at the leaf margins, the damage pattern looks even and repeated across many leaves rather than random. A deficiency usually appears on one part of the plant first, such as lower leaves for mobile nutrients or new growth for immobile ones.
Cannabis Nutrient Burn Treatment Guide
Nutrient burn also tends to follow an event: a stronger mix, a skipped watering, or a hot day that pulled more water than nutrients from the pot.
How to Fix Cannabis Nutrient Burn in Soil, Coco, and Hydro
Before You Start
- An EC or PPM meter
- A pH meter or pH drops
- pH up and pH down solutions
- Plain water, ideally low in dissolved solids
- A bucket or tray to catch runoff
How to Fix Nutrient Burn
- Stop all nutrient feeding, including boosters, calmag, and foliar sprays.
- Mix plain water and adjust the pH to 6.0 to 6.5 for soil, or 5.5 to 6.0 for coco and hydroponics.
- Water the container until runoff flows from the bottom, then keep pouring to push salts out. Use about two to three times the pot volume for soil.
- Collect the first runoff and measure its EC or PPM to see how far above your target you are.
- Repeat the flush every few hours or on the next scheduled watering until runoff EC drops close to your input reading.
- For hydroponics, drain the reservoir and refill it with fresh water adjusted to the correct pH, then run the system for a few hours.
- Let the medium dry back to its normal watering point before you water again.
- Wait 3 to 5 days, then feed at 50 percent of the strength you used before the burn.
- Raise the feed strength by small increments every 3 to 4 days only if new leaf tips stay clean.
What to Expect After the Flush
The browning will not reverse. Those leaves keep their damage until you remove them, and removing badly burnt leaves is fine if they are blocking light. Watch the newest growth at the top of each cola. If the fresh tips come in flat and green with no brown points, the flush worked. If tips brown again within a few days, your feed strength is still too high or your medium is holding salts.
Cannabis Nutrient Burn Solution: How to Stop It and Recover
Preventing a Repeat
- Measure EC or PPM every time you mix nutrients instead of scooping by eye.
- Water to 10 to 20 percent runoff in soil to keep salts from collecting.
- Check runoff EC once a week as a routine, not only when problems appear.
- Feed smaller amounts more often rather than one heavy dose.
- Reduce feed strength during heat spells when plants drink faster than they eat.