A citrus plant with dark-green leaves, white fragrant flowers and glowing fruit is a dream. For many, the way there fails at a single symptom: yellow leaves. And at the fateful reflex to reach for the watering can. Usually too much water is the cause, though, not the cure.
Citrus is not a difficult plant, but one that speaks plainly. Anyone who understands its language, above all reads the yellow of the leaves correctly, has years of pleasure. This article decodes the most common signals.
Reading yellow leaves correctly
Yellow is not just yellow. Before you do anything, look closely, because the patterns reveal the cause.
What the yellow means
- Whole leaves yellow, dropping
Usually too much water and rotting roots, often together with a too-cold spot. Water less, check drainage, set warmer and brighter.
- Yellow with green veins
An iron deficiency (chlorosis), often from too-limey water. Use soft water and counter it with an iron-containing citrus fertiliser.
- Uniformly pale green to yellow
A nitrogen or general nutrient deficiency. In the growing season the right citrus fertiliser is missing. Feed regularly but moderately.
- Yellow in the winter quarters
A light-warmth mismatch, too warm and too dark. That is the classic overwintering problem, more on it below.
Watering and feeding
Citrus likes neither waterlogging nor bone-dry. Water only when the top layer of soil has dried, and always let excess water drain. Important is low-lime, soft water, because citrus reacts sensitively to lime, which blocks iron uptake and triggers the typical chlorosis. Rainwater is ideal.
In the growing season from spring to late summer, citrus needs a special citrus fertiliser regularly, matched to its high demand. In winter, by contrast, there is little or no feeding.
Keep an eye on pests
Especially in the winter quarters, where the air is dry and the plant weakened, pests appear. Most common are scale insects, small brown bumps on shoots and leaf undersides, and spider mites, which leave fine webs and silvery-speckled leaves.
Check the plant regularly, especially under the leaves. Spotted early, scale insects can be wiped off and spider mites curbed with higher humidity and a rinse.
Yellow leaves are a signal, not thirst. First read, then act: soft water, citrus fertiliser, the right winter quarters. Water at every hint of yellow and you drown the plant.
The core rule for citrus care
Frequently asked questions
Why does my citrus plant get yellow leaves?
There are several causes. Whole yellow, dropping leaves point to too much water and root rot, yellow with green veins to iron deficiency from limey water, uniform pale green to nutrient deficiency. Look closely before you act.
Should I water more when leaves turn yellow?
Usually not, on the contrary. The most common cause of yellow leaves is too much water. Watering more then worsens the root rot. First check whether the soil is really too dry or rather too wet.
Which water is right for citrus?
Soft, low-lime water, ideally rainwater. Lime blocks iron uptake and triggers the typical chlorosis, the yellow with green veins. Hard tap water is unfavourable in the long run.
How do I feed citrus plants?
With a special citrus fertiliser in the growing season from spring to late summer, regularly but moderately. Citrus has a high nutrient demand. In winter there is little or no feeding.
Which pests attack citrus in winter?
Above all scale insects and spider mites, favoured by the dry, warm air in the winter quarters. Check the leaf undersides regularly. Spotted early, they can be wiped off or rinsed away.
