Plant problems · Nutrients · Any stage · Usually mild
Iron deficiency
What you see
- The newest leaves turn pale yellow while their veins stay green
- It starts at the top of the plant, older leaves look fine
- In bad cases new leaves come in almost white
Why it happens
Iron does not move inside the plant. The usual cause is a pH that is too high, so iron is present but locked out; overwatering and cold roots make it worse.
What to do
- Check and correct the pH first (soil 6.0 to 6.5, coco and hydro 5.5 to 6.0 helps iron)
- Let the medium dry out a little between waterings
- Only if pH is right, add a chelated iron or a micronutrient supplement
Next time
- Keep pH in range
- Avoid soggy roots
Easy to confuse with
- Magnesium deficiency: Yellowing between the veins of older and middle leaves while the veins stay green
- Sulfur deficiency: New leaves turn evenly lime green or yellow, veins included
- Light burn and light bleaching: The top leaves closest to the light turn yellow or white while their veins stay green
Not sure?
Take a photo of the top of the plant from above, showing the newest leaves and ask the Grow Doctor, or send it to the grow companion on Telegram.