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Kohlrabi is a tasty, versatile vegetable every gardener should try.
It grows in hardiness zones 3b through 10a. It’s part of the Brassica family, so it’s related to vegetables such as cabbages, Brussels sprouts, and broccoli.
Kohlrabi likes cool weather. But, even so, does that mean kohlrabi can grow in winter?
In most places, kohlrabi won’t survive throughout the winter. In order for kohlrabi to grow and thrive it needs temperatures of 40℉ to 75℉. In northern climates, kohlrabi harvests usually finish before the end of November. However, in some warmer zones, it can grow in the winter.
In this article, we’ll talk more about planting kohlrabi, how long it takes to grow, and how to keep your kohlrabi safe during those cooler months.
Can Kohlrabi Grow in Winter
Kohlrabi looks like a cabbage but it’s shaped like a turnip. Sometimes, it’s referred to as a root vegetable, though this is incorrect.
A kohlrabi bulb forms above the ground. Instead of the root, the kohlrabi stem swells to form the bulb.
Like most members of the Brassica family, kohlrabi prefers cool temperatures. But, it’s not as hearty as other members and it can’t survive prolonged cold weather spells.
Best Times to Plant Kohlrabi for a Fall Crop
For a fall crop, the best time to plant kohlrabi is mid-summer through fall, depending on your location.
Generally, your kohlrabi should be ready for harvest within a week or two of the first fall frost.
In colder, northern locations, plant kohlrabi around mid-summer. The further south you head, the later you’ll plant your fall kohlrabi.
And in the far southern zones, kohlrabi can and should be planted throughout the winter. As kohlrabi doesn’t like temperatures above 75℉, these zones are too hot in summer for kohlrabi.
In warmer climates, avoid planting too early and having your plants sprout during the heat of summer.
Heat stress is one of the reasons a bulb may not form. To learn of other reasons, head over to my article on why kohlrabi bulbs don’t develop.
This chart provides a general idea of kohlrabi planting times.
| ZONES | PLANTING TIMES |
|---|---|
| USA Zones 3a – 5b | April through June |
| USA Zones 6a – 6b | April through May |
| USA Zones 7a – 7b | April through June & September through October |
| USA Zones 8a – 7b | January through March |
| USA Zones 9 – 10 | October through February |
| Canadian Zones | May through July |
How Long Does It Take Kohlrabi to Mature
In General, kohlrabi takes between 50 to 70 days to mature. Some large varieties can take longer, even up to 130 days.
Because harvest times and kohlrabi size vary, it’s important the timing of your planting matches the variety you’re planting.
To learn more about growing kohlrabi, take a look at my beginner’s guide.
Can Kohlrabi Survive a Frost
Kohlrabi likes cooler weather and can survive moderate, and even hard, frost (24℉ – 28℉).
In fact, a light frost can actually help improve a kohlrabi’s flavor.
But, although it tolerates frost, it can’t take prolonged cold weather. In general, temperatures should remain above 40℉ – 45℉ degrees for your kohlrabi to grow correctly.
Some varieties handle cold better than others. They’ll maintain their shape without having problems such as cracking.
To be on the safe side, though, if nighttime temperatures will dip below freezing, then consider protecting your plants. You can use a frost blanket or row cover to keep them covered during the night.
If you can’t get to your Kohlrabi during an extended cold spell, then covering them is a must.
Also, consider harvesting them as soon as possible.
Kohlrabi Varieties
There are many delicious kohlrabi varieties. Here are 3 you might want to give a try.
Delicacy White – has a smooth texture and light green color. The shape is usually uniform and the flesh is crisp-tender. This kohlrabi is known for maintaining a tender texture even as it grows larger.
Giant Winter Kohlrabi – grows 8 – 10 inches in size, but still remains tender. It’s great for winter storage and can stay in the garden all winter long in warmer areas.
Kossak – is another large variety. Has white skin and dense white flesh. Harvest when it reaches about 8 inches in diameter. Kossak stores well, even up to 4 months, as long as you keep it cold after it’s harvested.
Final Thoughts
- Except in far south climates, kohlrabi doesn’t grow during winter.
- It does prefer cool temperatures and does not do well in the heat of summer.
- The further south you are, the later you can plant your kohlrabi for a fall crop.
- Kohlrabi tolerates frost but should be covered if continuous cold weather is expected.
- Aim to pick your kohlrabi within 1 – 2 weeks after the first fall frost.
