How do I fix pale leaves under led on cannabis?

Under LED lights plants can turn pale between the veins and produce small, light flowers even on a full feed. Give 18 hours of light in veg and 12 hours in flower. Add VitaSweet at 1 ml/L from week 3 to week 8. Check pH is 5.8–6.3.

Visual Guide

Pale leaves under LED.

Give 18 hours of light in veg and 12 hours in flower

← All problems

Yellowing between the leaf veins while the veins stay green

Illustration

Feeding & light

Under LED lights plants can turn pale between the veins and produce small, light flowers even on a full feed.

Looks like this

Yellowing between the leaf veins while the veins stay green
Pale new growth
Small, light flowers despite a full feed

Solve it with Vitaponix

VitaSweet →

Designed for LED growing: increases chlorophyll production and the use of magnesium and iron. 1 ml/L, weeks 3–8.

VitaFinish →

Maximises terpene production in the final weeks of flowering.

How to fix it

Give 18 hours of light in veg and 12 hours in flower
Add VitaSweet at 1 ml/L from week 3 to week 8
Check pH is 5.8–6.3

Why it happens

Light intensity or duration too low
Low chlorophyll production under LED
Poor use of magnesium and iron

Prevent it

Keep light intensity and duration consistent
Follow the official feeding chart

Official feeding chart

Light, vegetative: 18 hours
Light, flowering: 12 hours
VitaSweet: 1 ml/L, weeks 3–8

Doses and targets come from the official Vitaponix feeding chart. Vitaponix nutrients are plant nutrition, not pesticides or fungicides.

Prevent it next time

Get the full 10-week feeding schedule.

Open the feeding chart Shop Vitaponix →