Seed Saving: How to Save Kale Seeds

Kale is an easy plant to save seeds from. When you learn how to save kale seeds, you can have free seeds from your favorite variety year after year!

There are a few important things to know when it comes to how to save kale seeds, so keep reading to find out!

How to Save Kale Seeds

Leave kale in the ground to overwinter
Separate European kale from broccoli, cauliflower, cabbage, collards, kohlrabi and Brussels sprouts to avoid unwanted crossing
Allow the kale to bolt and produce seed stalks
When the kale seed pods are brown and dry, the kale seeds are ready to harvest. Cut or pull the stalks and put them upside down in a bag or box. Shake the seed pods around to release the seeds.
Dry the kale seeds in an airy place and store in paper envelopes to plant next year

Kale is a biennial, meaning that it normally has to be exposed to cooler temperatures and then flowers its second year. If some of your kale plants bolt their first year, don’t save seeds from them as this will give you mostly early bolting plants next year. Instead, wait till most of your kale plants go to seed to harvest the kale seeds.

The outer leaves can be harvested throughout the season its first year without harming your kale seed crop.

In most of the US, kale plants can be mulched and left in the garden all winter. The following spring, they will send up 4-5′ tall stalks with tiny yellow flowers that soon turn into kale seed pods!

If you live in a cold climate, you may have better luck saving seeds from Siberian kale. Mine has survived -25 degrees Fahrenheit and lived to produce seeds the following summer!

To make sure that your kale plants get pollinated well and set seeds, let a minimum of six plants flower. 20 plants is even better to preserve genetic diversity and avoid inbreeding depression (your plants getting less vigorous over time).

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Does Kale Cross with Other Vegetables?

There are actually two different species of kale commonly grown in gardens. The more common is European kale, or Brassica oleracea. This is the same species as most other cabbage family vegetables. The second, less common species is Brassica napus, or Ruso-Siberian Kales.

Why does the species even matter? Kale is pollinated by insects, and can cross with other plants from the same species that are flowering 1/2 mile or more away!

How do you know what species your kale is? Some kale seed packets and catalogs will tell you. You may also be able to contact the company if you want to find out for sure! Most kale varieties are European and belong to the first species, B. oleracea.

Kales belonging to Brassica oleracea:

Common Kale
Marrow-stem Kale
Borecale
Scotch Kale
Chinese
Ornamental and Flowering Kale
Curled
Cow Kale
Lacinato

The above European kale seeds can cross with other members of the cabbage family flowering nearby, including common cabbage, broccoli, cauliflower, collards, Brussels sprouts, kohlrabi and other varieties of European kale.

Kales belonging to Brassica napus:

True Siberian Kale
Hanover Salad
White Russian
“Wild Red”
“Red Ursa”
“Red Ruffled”
“Wild Garden Kales”
“Winter Red”

These varieties can cross with each other, as well as with rutabagas and rape plant (canola). They will not cross with members of the cabbage family. Typically Siberian types are easier to save kale seeds from simply because they don’t cross with as many other plants. Wild Garden Kale is my personal favorite from this group!

Kale will not cross with any of these plants if they are not allowed to bloom at the same time as your kale.

If two plants from the same species are blooming at the same time, they can be covered with fine mesh cages to keep out insects, but will then need to be hand pollinated.

Saving Seeds from Kale

After your kale flowers, each plant will grow dozens of long green seed pods.

When the seed pods start to dry out and turn brown, your kale seeds are ready to harvest!

Pull or cut the plants off. When the seed pods are completely dry, they will pop open if you gently press on the pod, releasing the small brown seeds. If the seed pods don’t easily pop open, the plants can be hung or placed in a box under shelter to dry further.

To quickly thresh (remove the kale seeds from the dry plants), you can place the top of the plant inside a paper bag and shake it to release the seeds.

Let your kale seeds dry in an airy place for another 1-2 weeks before storage. If kept dry and cool, kale seeds will last 4-8 years. You can read more about seed storage here.

Now you know how to save kale seeds!

Learn More About Seed Saving!

How to Save Seeds

Seed Saving: How to Save Tomato Seeds

How to Save Pepper Seeds

Seed Saving: How to Save Carrot Seeds

How to Save Squash Seeds

Seed Saving: How to Save Cucumber and Melon Seeds

How to Save Bean and Pea Seeds

How to Save Lettuce Seeds

Can You Save Seeds from a Hybrid Vegetable?

Learn everything you need to know to save seeds from your garden, all in as little as an afternoon, with our online seed saving course! You can find out more about the course right here!