Why Is My Cilantro Plant Turning Purple

Your cilantro plant turning purple is usually a sign of stress, and the most common culprit is cold temperature.
 
When cilantro plants turn purple, it often happens because of a pigment called anthocyanin.
 
This pigment builds up in the leaves and stems when the plant is exposed to stress like cold nights, nutrient issues, or root problems.
 
The good news is that a purple cilantro plant isn’t always a lost cause.
 
In this post, we’ll explore why is my cilantro plant turning purple, the reasons behind this color change, and what you can do to fix it.
 
Let’s dive in.
 

Why Is My Cilantro Plant Turning Purple?

If you’ve been asking “why is my cilantro plant turning purple,” the answer usually comes down to plant stress.
 
Cilantro is a cool-season herb, but it’s still sensitive to extreme cold, poor soil, and bad watering habits.
 
Here are the main reasons your cilantro plant turns purple.
 

1. Cold Temperatures Trigger Purple Coloring

Cold weather is the number one reason a cilantro plant turning purple happens.
 
When temperatures drop below 50°F (10°C), cilantro starts producing anthocyanins as a protective response.
 
These pigments act like a natural sunscreen and antifreeze for the plant’s cells.
 
So if your cilantro plant is turning purple after a cold snap, that’s your sign.
 
The purple color isn’t a disease—it’s your cilantro reacting to the chill.
 

2. Phosphorus Deficiency Causes Purple Leaves

A phosphorus deficiency can also make your cilantro plant turn purple.
 
Phosphorus helps cilantro with energy transfer and root development.
 
When it’s lacking, anthocyanins accumulate in the leaves, giving them that deep purple or reddish tint.
 
This often happens in cold, acidic, or waterlogged soil where phosphorus isn’t available to the roots.
 
If your cilantro plant turning purple comes with stunted growth, a phosphorus problem is likely.
 

3. Root Stress and Poor Drainage

Root stress is another reason your cilantro plant turns purple.
 
Overwatering or compacted soil starves the roots of oxygen.
 
When roots can’t function properly, the plant can’t absorb nutrients, and that stress shows up as purple coloring.
 
So if your cilantro plant turning purple sits in soggy soil, check the drainage right away.
 

4. Natural Maturity and Bolting

Sometimes a cilantro plant turning purple is just part of the plant getting older.
 
As cilantro matures and prepares to bolt, its stems and leaves can take on purple hues.
 
This is completely natural and often means the plant is shifting energy into seed production.
 
Once cilantro bolts, the leaves turn feathery and the flavor gets bitter, but the purple color itself isn’t harmful.
 

How to Fix a Cilantro Plant Turning Purple

Fixing a cilantro plant turning purple depends on what’s causing the stress.
 
Here are the best steps to bring your cilantro back to green.
 

1. Protect Cilantro From Cold

If cold is the reason your cilantro plant is turning purple, move it somewhere warmer.
 
For potted cilantro, bring it indoors or onto a sheltered porch when nights get chilly.
 
For garden cilantro, use a row cover or cloche to trap heat around the plant.
 
Temperatures between 60–75°F (15–24°C) keep cilantro happiest and greenest.
 

2. Feed With a Balanced Fertilizer

If phosphorus deficiency is behind your cilantro plant turning purple, feed it a balanced fertilizer.
 
Look for something with an even N-P-K ratio like 10-10-10 or a liquid fish emulsion.
 
Apply it every two to three weeks during the growing season.
 
This gives your cilantro plant the nutrients it needs to push out fresh green growth.
 

3. Improve Soil Drainage

If soggy roots are making your cilantro plant turn purple, fix the drainage.
 
Plant cilantro in raised beds or containers with drainage holes.
 
Mix in some perlite or coarse sand to loosen heavy soil.
 
Water only when the top inch of soil feels dry, and never let your cilantro sit in standing water.
 

4. Adjust Soil pH

Cilantro prefers soil with a pH between 6.2 and 6.8.
 
If your soil is too acidic, phosphorus locks up and your cilantro plant starts turning purple.
 
Add a little lime to raise the pH, or use a soil test kit to check where you stand.
 
Getting the pH right helps your cilantro plant absorb nutrients properly.
 

5. Prune and Harvest Regularly

If your cilantro plant turning purple is linked to bolting, harvest often.
 
Snip the outer leaves regularly to encourage fresh green growth.
 
Pinch off any flower stalks as soon as they appear.
 
This keeps your cilantro plant in the leafy stage longer and slows down the purple shift.
 

Is Purple Cilantro Safe to Eat?

Yes, purple cilantro is generally safe to eat.
 
A cilantro plant turning purple doesn’t make it toxic or dangerous.
 
The purple color comes from anthocyanins, the same antioxidants found in blueberries and red cabbage.
 
That said, if your cilantro plant is turning purple because it bolted, the leaves may taste bitter.
 
You can still use them in cooking, but the flavor won’t be as fresh as younger green leaves.
 

So, Why Is My Cilantro Plant Turning Purple?

Your cilantro plant turning purple is usually a reaction to cold temperatures, a phosphorus deficiency, root stress, or natural maturity.
 
The good news is that a cilantro plant turning purple is rarely fatal.
 
By protecting your cilantro from cold, feeding it properly, fixing drainage, and harvesting regularly, you can bring the green back.
 
So the next time you wonder why is my cilantro plant turning purple, you’ll know exactly what to check first.