12. August 2020

Why Is My Cabbage Splitting?

Two of my lovely cabbage heads look damaged all of a sudden. Has this happened to you too? This process is called cabbage splitting. Read more about how you can stop it below!

Bild på ett land med kål som står på rad i en sluttning.

One of my cabbage patches here on Oak Hill. I'm growing white cabbage and some leftover summer flowers here. But now, I have to worry about cabbage splitting!


Two of the white cabbages in my cabbage patch recently started splitting. You can't see it very well in the pictures yet. But I expect it to be very visible in just a few days. I noticed some questions about splitting cabbage on my social media platforms and wanted to write a bit more about it. Some people even assume that animals caused the problem.

But don't worry, it has nothing to do with uninvited guests or pest in your garden. This is actually a process that happens naturally. The cabbage heads can split when the plant starts to bolt. This is simply what happened to my cabbages.


Read more: Ten cabbage varieties and how to use them


I'm growing this cabbage by my cottage on a little hill in the south of Sweden, just outside the village Kalvsvik. This place is my own little sanctuary and I use it as an office too. I decided to create a small kitchen garden outside the cottage. A brand-new little cottage garden. If you want to know more about this project, you can check out my Oak Hill Cottage videos on Youtube.


Närbild på kål med trasiga blad.

This is what the cabbage splitting looks like. The outer layers are starting to break and the slugs can get to the tender, inner leaves.


Närbild på kålhuvud med trasigt blad.

A leaf broke apart. The upper part of it was damaged, so I removed it to keep it from rotting.


Damaged leaves

So, what you're looking for is any sign that the outer leaves of the cabbage head are starting to break apart. Think of it like this: The inner layers of the cabbage is expanding and the outer leaves can't keep up and start to break apart because of the tension. On one of my heads, even the main veins on the leaves started to break! And it can be even worse than that. The entire top layers of the cabbage can break and the head looks like it's split in half.

But why is this happening then? Well, a thick flower stalk is growing inside the cabbage head. It doesn't grow very tall though, more like a sturdy stem, but it does penetrate the leaves of the head. So, you might start off with a lovely round or perhaps pointed cabbage. But as it grows, it starts to expand and look more oval. Preferably, we want to harvest our cabbage before it bolts!


Närbild på odlingsbädd med kål och sommarblommor.

I'm growing my cabbage together with for example garden cosmos, flowering tobacco and snapdragon. But I won't be able to enjoy this combination much longer because of the cabbage splitting.


Bolting cabbage

It's not always clear why the cabbage suddenly bolts, but it most likely has something to do with the weather. The white cabbage I'm growing is a late variety that's supposed to be very hardy and can stay in the bed for a long time. So, it's not supposed to happen now.

But if the cabbage gets stressed, then it could start preparing to bolt. The flowering process is actually the main point, since this is how the plant produces new seeds and later on, new cabbage plants. This normally happens after overwintering though, in year two. But this can happen sooner too, depending on the circumstances. It can happen if it's for example too dry, too hot, too cold, too little fertilizer in the soil or similar.

The cabbages I have here grow in an entirely new bed up on a rocky little hill. There's barely any soil here at all, just a big pile of weeds covered with landscape fabric and a nice layer of grass clippings. You could say that these cabbages had a lot to complain about, so I'm actually surprised I got these nice heads at all. I'm not at all upset that the cabbages are starting to bolt now!


Read more: It's all about the cabbage


Närbild på kålhuvud med lite skador i bladen.

I decided not to use a row cover on my cabbage, because I wanted to be able to pick any slugs instead. But we have surprisingly few pests on them this year!


Trädgårdsbild med en stor bädd i sluttning med kål.

The cabbage splitting isn't that widespread yet, thankfully. It's primarily affecting the smaller and less developed cabbages. I'm keeping an eye on them now so they don't start to bolt!

What to do about cabbage splitting?

If you notice that your cabbage is starting to split, then I recommend harvesting it as soon as you can! There's no stopping a bolting cabbage after all, and it might break apart even more if you decide to wait. This is not only an aesthetic issue. The cabbage is actually more vulnerable to pests and diseases when it starts to split. Worst case scenario, the cabbage will rot. And you can't save them after that. Rotten cabbage smells really bad too, and the smell tends to spread to any neighboring plants. So, that's why you should just harvest it and eat it as soon as you can when you see the first signs of your cabbage splitting.

I'm growing a lot of cabbage this year, and I was planning on fermenting this batch!
/Sara Bäckmo

2 responses to “Why Is My Cabbage Splitting?”

  1. Rich says:

    :I came across your post, because me cabbage is splitting - early - and I was looking for solutions. Apparently, in addition to bolting, another cause - and maybe the primary one - is that the plant is taking up too much moisture. The innards of the head expand faster than the outer layers can accommodate. If you can control the moisture to a more even level, it should help with splitting. A heavy soak, or rain, after a dry spell seems to set them off.

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