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Onion · Allium cepa

Why are my spring onion leaves turning yellow?

Yellowing leaves on spring onions often signal that the plant is struggling with its water intake or a fungal issue. Check the soil moisture first to see if you are overwatering or if the plant is drying out too much.

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yellow leaves on a plant
Photo: Trio3D, CC BY-SA 4.0

Check these first

  1. Check the soil moisture level with your finger.
  2. Inspect the undersides of leaves for fuzzy growth.
  3. Ensure the pot has proper drainage.

Likely causes

  1. Overwatering

    Most likely

    How to tell: The soil feels soggy and the base of the onion may feel soft or mushy.

    What to do: Let the top inch of soil dry out before watering again. Ensure your container has drainage holes so excess water can escape.

  2. Downy Mildew

    Possible

    How to tell: You notice a purplish gray fuzzy growth on the leaves before they turn yellow.

    What to do: Remove the affected leaves immediately to stop the spread. Improve air circulation around your plants by spacing them further apart.

Yellow leaves on other plants

Find out what's wrong with your onion

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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When to worry

If the yellowing spreads rapidly across the whole plant or the base turns to mush, the plant is likely beyond saving.

Stopping it coming back

Water only when the top inch of soil is dry and keep foliage as dry as possible by watering at the base.

Onion: yellow leaves? Check yours with a photo

Every plant is a little different. Take a photo of your onion and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Can I eat yellowing spring onions?
If the yellowing is caused by simple underwatering, the green parts are usually fine. If it is due to mildew or rot, discard the plant.
Does yellowing mean I need fertilizer?
Sometimes, but check for water issues first. If the soil is healthy, a light application of balanced liquid fertilizer might help.

Guides to these causes

More problems with Onion

Back to the Onion guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.