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Cilantro leaves turning purple is usually a sign that your plant is stressed and it’s rarely a sign of disease.
If you’ve noticed your cilantro leaves turning purple and you’re wondering what’s going on, don’t panic just yet.
This color change is actually your cilantro plant’s way of telling you something in its environment isn’t quite right.
In this post, we’ll dig into why your cilantro leaves are turning purple, what it means for your plant, and how to fix it so you can get back to harvesting fresh leaves.
Let’s get growing.
Why Are My Cilantro Leaves Turning Purple?
When cilantro leaves turning purple becomes noticeable, it’s typically because of one or more of these common issues:
1. Cold Temperatures Shock the Plant
One of the most common reasons for cilantro leaves turning purple is cold stress.
Cilantro prefers mild weather, ideally between 50°F and 85°F.
When temperatures drop below 50°F, the plant’s cells respond by producing anthocyanins, the purple pigments you’re seeing.
These pigments act like a natural antifreeze, protecting the plant from the cold.
If you’re growing cilantro in late fall or early spring and your cilantro leaves turning purple, cold nights are likely the culprit.
A frost cloth or row cover can help keep your plant warm during chilly spells.
2. Phosphorus Deficiency in the Soil
Another reason for cilantro leaves turning purple is a phosphorus deficiency.
Phosphorus is essential for healthy leaf and root development.
When cilantro can’t take up enough phosphorus, the leaves turn a deep purple or reddish hue, often starting at the edges and veins.
This can happen in cold soil too, since plants struggle to absorb phosphorus when the ground is chilly.
A soil test can confirm whether your cilantro leaves turning purple is tied to low phosphorus.
Adding bone meal or a phosphorus-rich fertilizer usually corrects the problem within a couple of weeks.
3. Poor Soil Drainage and Root Stress
Cilantro hates soggy roots.
If your soil drains poorly, waterlogged roots can’t absorb nutrients properly, and that stress often shows up as cilantro leaves turning purple.
Root rot and fungal issues thrive in wet conditions, compounding the problem.
Make sure your cilantro is planted in loose, well-draining soil, ideally in a raised bed or pot with drainage holes.
Water only when the top inch of soil feels dry and cut back if you notice standing water.
4. Sudden Temperature Swings
Cilantro leaves turning purple can also happen after a sudden shift in temperature.
A warm afternoon followed by a cold night stresses the plant, triggering that same anthocyanin response.
If your cilantro leaves turning purple appeared right after a cold snap, this is almost certainly why.
Mulching around the base helps insulate the roots and smooth out temperature swings.
5. Natural Aging and Bolting
Sometimes cilantro leaves turning purple is simply part of the plant’s natural life cycle.
As cilantro ages and starts to bolt, its leaves can take on purple and reddish tones before going to seed.
If your cilantro leaves turning purple comes with tall flower stalks, your plant is done producing tender leaves.
Sowing new seeds every few weeks keeps you in fresh cilantro all season.
How to Fix Cilantro Leaves Turning Purple
Fixing cilantro leaves turning purple starts with figuring out which stressor is at play.
Move potted cilantro indoors or cover outdoor plants when temperatures dip below 50°F.
Test your soil and amend it with compost or bone meal if phosphorus is low.
Improve drainage by mixing in perlite or planting in raised beds, and never let your cilantro sit in standing water.
Water deeply but less often, and mulch to keep soil temperatures steady.
If your cilantro leaves turning purple because the plant is bolting, pull it and start fresh seeds.
Once you address the root cause, new growth should come in green and healthy within a week or two.
Can Purple Cilantro Leaves Still Be Eaten?
Yes, you can still eat cilantro leaves turning purple.
The color change doesn’t make the leaves toxic or unsafe.
However, stressed cilantro often tastes bitter or less flavorful than healthy green leaves.
If your cilantro leaves turning purple because of cold or a nutrient deficiency, the flavor may be off.
Taste a small leaf first and decide from there.
If the leaves are tough or the plant has bolted, it’s better to compost them and replant.
So, Why Are My Cilantro Leaves Turning Purple?
Cilantro leaves turning purple is a stress response, most often caused by cold temperatures, a phosphorus deficiency, poor drainage, sudden temperature swings, or the plant bolting.
It’s rarely a disease, and in most cases, it’s a fixable problem.
Check your growing conditions, adjust as needed, and your cilantro leaves turning purple should soon be a thing of the past.
Hope this post has helped you understand exactly why your cilantro leaves turning purple and how to get your plant back to healthy green growth.