Nutrient burn during flowering means your plant is taking up more mineral salts than it can use. The fix is to stop pushing fertilizer: leach the root zone with pH-balanced water, drop your feed strength by 20–30%, and judge recovery by new growth rather than the leaves already damaged. Do not add more supplements, boosters, or calmag to compensate, and do not harvest early over a few burnt tips.
how to fix nutrient burn in cannabis plants
Prerequisites
- pH-adjusted water (6.0–6.5 in soil, 5.5–6.2 in coco or hydro)
- An EC or PPM meter, plus a runoff catch tray
- Your current nutrient schedule and the last two feeding amounts
- Clean, sharp scissors for removing dead tissue only
How to Fix It
- Confirm the diagnosis before acting: crisp brown tips and edges, dark clawing leaves, and a waxy shine point to excess salts; uniform pale yellowing from the bottom up is usually hunger.
- Measure the EC or PPM of your feed and the runoff. Runoff reading well above the input confirms salt buildup.
- Stop all nutrient solution and run pH-adjusted plain water through the pot until runoff comes out close to your input number—typically two to three times the pot volume in soil, less in coco.
- Let the medium drain fully and skip the next scheduled feeding, giving the plant plain water only.
- Resume feeding at 20–30% below your previous strength once new leaf tips come in clean, usually within one to two weeks.
- Remove only fully dead, crispy leaf material with clean scissors; leave damaged-but-living leaves in place until they fade.
- Hold the environment steady—stable temperature, moderate humidity, and steady airflow—while the plant recovers.
- Log every feed and runoff reading so you can spot the climb before it burns the next round.
What Not to Do
Do not flush repeatedly week after week; repeated leaching strips phosphorus and potassium exactly when buds are swelling. One corrective flush plus reduced feed is enough for most cases. Do not stack bloom boosters with a base nutrient line that already carries full phosphorus, and do not chase a perfect leaf—late-flower fade on lower leaves is normal senescence, not a deficiency to correct.
How to Adjust EC for Marijuana Nutrient Burn: Buying Guide
Timing and Yield Impact
Mid-flower burn costs little if you act within a few days. Severe burn that reaches the sugar leaves around buds can slow ripening and leave a harsh cure. If buds are within two weeks of harvest, water only and ride it out rather than attempting a heavy flush.