Nutrient burn shows up as crispy, brown, curling leaf tips and dark green foliage, and it means you fed too much. A deficiency looks like the opposite: pale, yellowing, or spotted leaves that signal too little of something. Burn works from the tips inward, while deficiencies usually start with color loss across the leaf.
Reading the two problems side by side
The fastest way to tell them apart is to look at where the damage starts and what color the healthy tissue is. Burnt plants tend to be lush, almost too green, with the trouble confined to the very ends of the leaves. Deficient plants lose color first, and the tips stay intact until the problem gets severe.
We see both constantly at our Colorado nursery, often on the same plant, because a grower overcorrects one and creates the other. Slow down and diagnose before you reach for the bottle.
How to spot nutrient burn
Classic burn starts at the leaf tips and margins. They turn yellow, then tan, then brittle and brown, and the tips often hook or claw downward. The rest of the leaf stays deep green, sometimes glossy. You may also notice a dark, waxy sheen and slight tip clawing, which points to nitrogen toxicity specifically.
Burn is cumulative. Once a tip is fried it will not heal, so judge your fix by whether new growth stays clean, not by whether old damage reverses.
How to spot a deficiency
Deficiencies announce themselves through color. Nitrogen shortage yellows the oldest, lowest leaves first and moves up. Magnesium leaves green veins on a yellowing leaf. Calcium and potassium bring brown spots and rusty margins. Because plants pull mobile nutrients from old growth to feed new growth, mobile deficiencies show at the bottom while immobile ones show at the top. Our full cannabis nutrient deficiencies walkthrough maps each symptom to its cause.
Symptom, cause, and fix at a glance
| What you see | Likely cause | First move |
|---|---|---|
| Brown crispy tips, very dark green leaves | Overfeeding (nutrient burn) | Flush with plain pH’d water, cut feed strength |
| Pale lower leaves yellowing upward | Nitrogen deficiency | Feed a balanced veg nutrient |
| Yellow leaf with green veins | Magnesium deficiency | Add cal-mag, check pH lockout |
| Rusty spots, curling margins | Calcium or potassium shortage | Supplement cal-mag, correct pH |
How to fix nutrient burn
- Stop feeding and flush the medium with three times the pot volume of plain, pH-corrected water.
- Let the pot dry to a proper wet-to-dry cycle before watering again.
- Resume at half your previous nutrient strength and watch the next set of leaves.
- Trim only the fully dead, crispy tips so the plant stops spending energy on them.
How to fix a real deficiency
- Confirm your runoff pH first, since lockout mimics a shortage even when nutrients are present.
- Match the symptom to the missing element using the table above.
- Feed the correct nutrient at a moderate dose, not a rescue megadose.
- Give it four to seven days; new growth should green up while old damage stays put.
Most “deficiencies” we get asked about are actually pH lockout. If your numbers drift outside the sweet spot, the roots cannot absorb what is already in the pot. Keep a meter handy and lean on our cannabis pH guide to dial in the range for soil versus hydro.
How to prevent both
Feed to the plant, not to the calendar. Start young plants and freshly rooted clones at quarter to half strength, then step up only when they ask for it with fast, hungry growth. A steady program, laid out in our cannabis nutrients feeding guide, prevents the whipsaw of burning, flushing, and starving. Check runoff EC and pH weekly so you catch drift before leaves show it.
Frequently asked questions
Can a plant have burn and a deficiency at once?
Yes, and it is common. Overfeeding one element can lock out another, so you get burnt tips and a pale, deficient middle at the same time. Flush first, then feed a balanced base and reassess.
Will burnt tips grow back green?
No. Dead tissue stays dead. Judge your correction by the health of new leaves at the top of the plant, and trim the crispy ends only if they are fully dry.
Why do my clones burn so easily?
Young roots are sensitive and take up little at first. Freshly rooted clones need gentle feeding, so keep them at quarter strength until they establish and start stretching.
Is pH really that important?
It is the single biggest cause of fake deficiencies. Even a perfect nutrient mix is useless if pH sits out of range and the roots cannot pull it in.
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