Why Is My Cauliflower Turning Purple and How to Solve It!

why is my cauliflower turning purple
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Cauliflower is a delicious vegetable a lot of people love having, thanks to its versatility in how to cook it. You can also plant it on your own, with cauliflower being part of the Brassica family, which is grown for its head, which is composed of something called curds, or clusters of immature flowers.

When growing or purchasing cauliflower in the store, you notice that it has a white or creamy head. However, variations might be possible because of light levels, climatic conditions, or the environment it grows in.

In fact, you might have noticed that there is a purple tint, or the entire head turned purple! That’s why you may have asked yourself, “why is my cauliflower turning purple?”

Read on to learn all about your cauliflower turning purple and if it’s safe to consume.

Why Is My Cauliflower Turning Purple?

1. Climate Conditions

Cauliflower needs a daytime temperature between 21-29 degrees Celsius. When you plant cauliflower, you have to be wary of the weather, since the plant has to be large enough to maintain the development of its large head. If not, a late-season frost may end up killing or harming a young plant.

When they mature, varieties will be able to tolerate the brief exposure to cold temperatures of up to the negative degrees.

2. The Soil’s Nutrients

Cauliflower needs to grow in soil that’s rich in nitrogen and potassium. However, too much nitrogen may cause purple discolorations, creating premature head growth while the leaves aren’t big enough to cover the curds, protecting it from the sun. Furthermore, having insufficient phosphorous levels may cause purplish tints on cauliflower, so you’ll need to check the soil nutrient levels before planting and adding more compost or nutrients.

3. Ricing

When cauliflower heads mature rapidly, a condition known as ricing may occur, which is a condition when the curd would develop small flower buds appearing fuzzy or velvety. That’s why you’ll need to harvest the cauliflower head before the condition happens.

You can prevent ricing by maintaining optimum levels of soil moisture and fertility, and to keep the plants from experiencing dry spells, extreme cold or hot temperatures, and also low temperatures after planting, high temperatures during curd development, or late supplying of nitrogen.

4. Any Diseases?

Downy mildew fungus may develop in cauliflower plants during cool weather and wet conditions. This can attach cauliflower, which causes it to discolor not only to purple but yellow and brown. You need to control the fungus by applying the recommended amount of fungicide to your plants and monitor it every few days.

Can I Eat Purple Cauliflower?

What if you do end up growing purple cauliflower, will you still be able to eat it or toss it out?

Don’t despair, as you can still eat purple cauliflower and it’s perfectly safe to cook and consume. It may have a bit of an off-flavor, and it’s better to consume it raw, since cooking it may increase its “offish” flavor, too.


Heating your purplish florets may change its color from purple to gray, or even slate blue, particularly when you have hard water or alkaline pH levels. These are NOT appetizing-looking hues.

But if you don’t like consuming raw cauliflower and want to cook a dish, then you can add a bit of cream of tartar or vinegar to its water, which can minimize the color changing.

How to Prevent Cauliflower With Purple Tinges

Now that you know why your cauliflower is turning purple, the next question is: How can you prevent it from happening again? Here are some tips you can follow:

  • Invest in a self-blanching cauliflower variety that’s been made to reduce curd-tinting problems.
  • Blanch and/or cover your cauliflower head while it’s developing with any surrounding leaves. Even if your cauliflower shows some tint around its edges, you need to blanch it, keeping it away from the sunlight. Draw your cauliflower’s surrounding leaves around the head of your cauliflower and tie its leaves using garden twine or rubber band, holding its leaves closed.
  • If you haven’t planted your cauliflower yet, you can prevent the purple tinge by scheduling its development during cooler fall months, like September and October. This is because lengthy and hot summer days would cause the purple color in cauliflowers. I recommend having a proper planting time, with the cauliflower having daytime temperatures between 21-29 degrees C, so you’ll need to figure out when your variety matures to time your seeding and harvesting.
  • Learn more about planting your cauliflower properly, starting by learning how to transplant it once it has 3-4 true leaves before planting it outside. It should be in the ground 2-3 weeks after the date of your area’s last expected frost, removing all competitive debris and weed, ensuring that it’s well-tilled and compost.
  • Keep your cauliflower well-cared for as it grows by watering it a few times a week to maintain moist soil. Also, watch out for pests and diseases to combat and prevent them from killing off your plant.
  • Harvest your cauliflower properly, which would be fully grown 7-12 days after you blanched them. When the head matures, loosen its leaves over the cauliflower head, cutting the main stem. After harvesting the cauliflower, pull the greens and place them in the compost.

Do you want to learn more about growing cauliflower properly to prevent purple tinges? Check out this informative video:

Wrapping It Up

Seeing purple cauliflower may seem odd, but it’s a common occurrence that happens to various gardeners. There are different causes, mainly due to the environment it grows in, and when you’re able to pinpoint the problem, you can start having properly grown cauliflower to harvest. And if you do get purple cauliflower, not to worry, as it’s still safe to eat!

I hope that this article answers your question, “why is my cauliflower turning purple?” Now that you know the answer, start looking into what you can do to help keep your cauliflower growing properly (and in good color).

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