A cannabis nutrient burn treatment comes down to three steps: flush the growing medium with pH-balanced water, cut the feed to half strength, and watch new growth for the next 7 to 14 days. Burnt tips will not turn green again, so judge recovery by fresh leaves, not old damage. Most plants pull through with little effect on the final harvest.
Cannabis Nutrient Burn Prevention: Buying Guide for Meters and Nutrients
What does nutrient burn look like on cannabis?
Nutrient burn starts at the leaf tips and moves inward along the edge. The tissue turns brown or copper and curls upward before it crisps. Leaves around the damage often look dark green and waxy, which signals more nitrogen and salts than the plant can use.
- Brown or burnt tips on middle and lower leaves
- Edges that curl up like a canoe
- Dark, glossy leaves that feel stiff
- Crisp patches that crumble when you touch them
- Brown speckles on sugar leaves in severe cases
How do you tell nutrient burn from other problems?
Burn begins at the tip and moves toward the base of the leaf. A nitrogen deficiency yellows from the bottom of the plant up. Light burn hits the leaves closest to the lamp and bleaches the top of the canopy. pH lockout shows as yellowing between veins or spots in the middle of the leaf, not at the tip.
What causes nutrient burn?
Burn comes from more fertilizer salt in the root zone than the plant can take up. Leftover salts pull water away from the roots, and the plant sits in a concentrated solution. Common triggers:
- Mixing nutrients above the label rate
- Feeding full-strength doses to seedlings, clones, or autoflowers
- Salt buildup in reused soil or coco coir
- Stacking boosters on top of a complete base nutrient
- Pots with poor drainage or no runoff
- Water evaporating between feeds, which raises EC in the pot
How do you treat nutrient burn step by step?
- Confirm the diagnosis. Check runoff EC and pH, and note where the damage started on the plant.
- Flush the medium. Run pH-balanced water through the pot until runoff EC drops close to your input EC.
- Cut the feed. Drop to half strength or give plain water for 2 to 3 waterings.
- Reset pH. Aim for 6.0 to 6.5 in soil and 5.5 to 6.0 in coco or hydro.
- Trim dead tissue. Remove leaves that crumble. Leave leaves with minor damage in place so they keep working.
- Wait for new growth. The next two sets of leaves tell you whether the fix worked.
- Feed again at a lower rate. Build the dose back up in small steps and track runoff EC.
How much water does a flush take?
In soil, push about three times the pot volume of pH-balanced water through the medium. A 5-gallon pot takes around 15 gallons of water. In coco coir and hydro, a gentler flush works better: feed a low-EC solution for 2 to 3 days instead of dumping plain water, which keeps the plant fed while salts clear.
Can you save burnt leaves?
No. Dead tissue does not repair, and the burnt tip stays brown for the rest of the grow. Watch the newest growth instead. Clean tips on fresh leaves mean you caught the problem in time.
Does the growing stage change how much you feed?
Yes. A seedling or clone uses a fraction of what a flowering plant takes, so a dose that suits a mature plant will burn a young one. Autoflowers also finish on less feed than photoperiod plants. Match the dose to the stage and raise it in steps as the root system fills the pot.
Will nutrient burn reduce yield or CBD content?
Mild burn costs little. Plants tolerate brown tips and finish on schedule. Severe burn that reaches the middle of the leaf, combined with stalled growth, cuts yield because the plant spends energy on repair instead of flower mass. No solid data shows that nutrient burn shifts CBD levels on its own; any effect runs through overall plant health.
How do you prevent nutrient burn?
- Start at a quarter to half of the bottle rate and raise it over 2 weeks.
- Meter EC or PPM at each feed and keep a log.
- Water to runoff so leftover salts leave the pot.
- Keep a separate, weaker schedule for autoflowers and young plants.
- Flush coco on a schedule every 2 to 3 weeks.
- Change the reservoir in hydro every 7 to 10 days.
Frequently asked questions
Is nutrient burn the same as nutrient lockout?
No. Burn means too much salt in the root zone. Lockout means pH drifted out of range and roots cannot take up nutrients that are present. Lockout shows as deficiency symptoms, not burnt tips.
Does flushing shock the plant?
A short flush does little harm to a healthy plant. Long stretches of plain water do, because they starve it. Keep the flush tight and return to a light feed.
How long does recovery take?
New growth looks normal within 7 to 14 days. A plant with severe burn can take 3 weeks to fill back in. Plants in flower recover slower than plants still in veg.
Should you feed after a flush?
Yes, at a lower rate. Resume at half strength once runoff EC drops back into range, then raise it as the plant responds.