Nutrient burn shows as crisp brown or yellow tips on older leaves that curl up and feel dry. A deficiency shows as pale tissue on new growth, yellowing between green veins, or brown spots that spread inward from the leaf edge. Burn means the root zone holds more salt than the plant can take up; deficiency means one nutrient is missing, or the pH has drifted and the plant cannot reach what sits in the pot.
Can Plants Recover From Nute Burn? A Practical Recovery Guide
Both problems fade leaves and stall growth, so the tell is location. Damage that starts on the bottom leaves points to burn or a mobile nutrient shortage. Damage that starts on the top leaves points to a shortage of an immobile nutrient such as calcium or iron.
nitrogen burn on cannabis leaves
What are the first signs of nutrient burn vs deficiency?
- Nutrient burn: tips turn brown or bronze first, edges curl upward, the rest of the leaf stays dark and waxy, and the damage creeps from the tip inward.
- Nitrogen shortage: the whole older leaf fades from green to yellow, starting at the bottom of the plant, with soft tips and no crisp edges.
- Magnesium shortage: yellow sits between veins while the veins stay green, on middle and lower leaves.
- Calcium shortage: new leaves show brown spots, curl at the edges, and the growing tip looks twisted.
- Potassium shortage: brown, scorched edges on older leaves, but the tissue stays soft rather than crisp.
One look is not enough. A plant with burnt tips and pale lower leaves has two problems at once, and the fix for each pulls in opposite directions.
revive cannabis plants from nutrient toxicity
Why does a pH or EC reading settle the argument?
Leaf color tells you what the plant looks like. A runoff reading tells you why. Salt buildup pushes EC up, which locks out water and shows as burn, while a pH outside the uptake window makes a well-fed plant look starved.
what does nutrient burn look like on cannabis
Test the runoff, not the feed. Catch the first ounce that drains from the pot, measure EC and pH, then compare those numbers to what went in. A runoff EC far above the input means salt is stacking up, and a runoff pH that has slid below 5.8 or above 7.0 in soil points to lockout rather than hunger.
Which diagnosis tool is worth buying first?
Pick: a dual pH and EC pen. It answers both questions in one pass, takes about a minute per plant, and costs less than a bottle of most nutrient lines. Everything else on this list is a backup for growers who know their pH holds steady.
- What it does: reads the pH and salt strength of your feed and your runoff.
- Why it wins: it separates too much food from food the plant cannot reach, which is the exact fork between burn and deficiency.
- Watch for: pens drift. Calibrate with fresh pH 4.0 and 7.0 solution every two to four weeks, and store the probe wet.
- Rough cost: a decent dual pen runs $40 to $90. Cheap units with no calibration option waste the money.
What are the other options, and who do they suit?
EC-only pen
A conductivity pen costs half as much and handles the salt question well. It suits growers who run reverse osmosis water, mix their own salts, and check pH with drops or a separate meter. It cannot tell you why a plant starves, so it pairs poorly with hard tap water.
Soil test kit
For living soil and dry amendments, a lab or drop-style soil kit beats a runoff pen. These kits read available phosphorus, potassium, and pH in the medium itself. They run slow (days for a lab, minutes for drops) and give no read on feed strength, so treat them as a check on the soil, not on tomorrow's watering.
Runoff tray and clean syringe
This is the cheapest way to collect a sample: a saucer, a turkey baster, and two small cups. It suits anyone who owns a pen but still pours straight through the pot and lets the runoff vanish. Pull 20 to 30 ml from the saucer within a minute of watering, before it evaporates and concentrates.
Dosing syringe and a feed chart
Most burn starts with a measuring cup and a guess. A 60 ml syringe plus the nutrient brand's own chart keeps mixes repeatable, which removes the cause instead of diagnosing it. Pair it with a written log of date, volume, and EC so a pattern shows up before the leaves do.
Can a plant show burn and deficiency at the same time?
Yes. Salt buildup in the root zone blocks water uptake and locks out calcium, magnesium, and potassium, so the tips scorch while the middle of the leaf yellows. The fix is a flush with pH-adjusted water, then a return to a weaker feed. Adding more nutrients makes it worse.
What numbers should you check before you change anything?
- Input EC: feed strength in veg often lands near 1.2 to 1.6 and rises in flower. Your nutrient brand's chart beats any general range.
- Runoff EC: a reading well above the input means salt is collecting. A reading far below means the plant is eating faster than you are feeding.
- pH: soil grows sit near 6.0 to 6.8, coco and hydro near 5.6 to 6.2.
- Runoff volume: aim for 10 to 20 percent of what you poured in. Less than that and salts stay behind.
Bottom line
Read the leaves for location, then read the runoff for cause. Tips and edges on old leaves mean burn; pale new growth or striped veins mean deficiency. A calibrated pH and EC pen splits those two in under a minute, which is why it takes the first slot in the toolkit and everything else follows.