How to Save Kale Seed – Made Easy!

Learn to save your own kale seeds to produce a crop of seed for next year’s vegetable garden that is completely adapted to your growing conditions. Kale is a biennial plant and, while they’re not the easiest to save seed from, we’ve shown you practical ways to make this process work for your area. Lots of tips and troubleshooting included. Be bold this year and learn how to save kale seed! 
This post has been updated from its original publication in 2012 to better serve our readers. Go seed savers!

More Seed Posts for Later:

Do I Need to Buy Organic Seed?

Winter Sowing – Starting Seeds Outdoors

Seed Saving for the Easily Confused

Just a heads up, this article is comprehensive, so grab a milkshake and kick back.

Why Are Biennials Hard Seed Saving Plants?

Kale is a biennial plant. Biennial means:

1. Something that lasts or lives for two years.
2. Or something that happens every second year.
3. A plant that has a life cycle that usually takes two growing seasons to complete.

If you’re new to saving seeds, I suggest you start with an annual plant. This is one that will start, mature, set seed, and die back all in one growing season.

Annual plants are much simplier to save seed from because you don’t have to worry about the plant over-wintering. This means that the plant will survive winter without any special measures taken (like protecting the plant from frost).

• If you live in a mild winter area without severe killing frosts, then you may not want to have one plant take up the same space for two years.
• If you live in a severe winter area, this will mean you need to take special precautions for winter care of the kale plant.

We will talk a lot more about this in the body of the article, but I want you to put that little nugget in your mind now.

If you’re new to seed saving and you start reading these instructions and your eyes start to cross and your brain starts to hurt, try a different seed save this year! I can suggest the following as great starter seed saving projects:

Saving Tomato Seeds us here at Homestead Lady

How to Save Basil Seeds from Harmony Meadow Homestead

Save Lettuce Seed from Stone Family Farmstead

You still have to concern yourself with climate, cross-pollination, and other typical seed saving parameters. However, these plants are simply easier to work with when starting out with seed saving than those pesky biennials.

Why Save Kale Seed If It’s Hard?!

You may want to learn to save kale seed yourself if you’re simply a frugal gardener and are trying to keep the cost of your seed purchases down every year. That’s a perfectly good reason to learn how to save your own seeds!

If you’ve had even a little experience saving seed, though, you soon realize that there are other benefits. For one thing, growing kale in your backyard means that you’re raising a plant that over time can become completely adapted to your growing conditions.

• The phrase gardeners often use for that adaptation is acclimation, or acclimitazation.

If you can save seeds from these adapted plants that perform the best, you can slowly produce new generations of plants that are stronger and even better suited to your garden.

This is of enormous benefit if we’re really trying to grow our own food! Genetically strong plants, produce more food and endure changes in weather and other pressures much better than those less adapted to your garden.

Join a Seed Saving Group!

Another benefit for increasing the health of your plants is that, if you learn to save kale seed yourself, you can join seed saving groups and share your seed around. You can also acquire new seed stock to try out in your garden.

• If you don’t have a group that’s close enough to you to be considered local, you can learn to start your own seed saving group where you live!

The more local gardeners who save and share seed, the better and stronger everyone’s gardens will be!

Consider that a lot of your favorite seed houses may not sell seed that’s been developed anywhere near you. Most seedhouses have a lot of growers in diverse places, but they probably aren’t as local to you as your backyard or your neighborhood!

What Makes Saving Kale Seed Tricky?

The whole family of plants to which kale belongs is called Brassica oleracea (hereafter referred to as B. oleracea for short.) Well known players in this family are broccoli, cauliflower, and cabbage.

All plants in this family are biennials; remember, that means they take two years to grow, flower, set seed, and then die.

• Although kale is very frost hardy, in severe winter areas, you will need to dig up and bring in your kale plant to ensure it doesn’t freeze to death before it has time to set seed.

If you live in a very temperate area without harsh winters, you can easily get your kale plants to the seed setting stage of development without a lot of fuss.

• However, temperature isn’t the only challenge to contend with!

The other problem with this delicous plant is that nearly all members of the family will cross-pollinate each other.

What’s the Problem with Cross-Pollination in Seed Saving?

Cross-pollination is simply the transfer of pollen from one plant to another.

• This is usually accomplished by wind or insects, or both, and it’s usually a great thing.
• When plants of the same species and type pollinate each other, you can end up with great new seed to plant in your garden for next year.

When you cross-pollinate, you end up with characteristics from one plant blended with those of another. So the next generation of plants from that crossing will be a mix of both parent plants.

• As I said, this is great as long as you’re crossing the same type of plant within the family. For example, crossing a collard with another collard.
• In fact, you can mix and match collard varieties to get the characteristics you like best.

However, it turns into a bit of a mess if you accidnetally cross a collard with cauliflower. Since these crops are pollinated by wind and bugs, your plants can pick up pollen without you having much control!

• Can you imagine a collard green with a small cauliflower head at the tip? 

When you cross-pollinate plants with distinct characteristics, you often end up with genetic weirdness in the offspring plants. Like Frankenstein plants.

• As an example, insects accidentally crossed a pumpkin and a watermelon one season in my garden. The seed left behind sprouted and produced a fruit with a hard, green rind and a pale pink flesh that tasted like unripe, boiled pumpkin. 

Bleh. The goats wouldn’t even eat it!

So, you need to ensure that you don’t have any other B. oleracea plants flowering and being pollinated in your garden at the same time your kale plant is flowering.

• Techically, you also need about 1/2 mile to 1 mile worth of clearance in your neighborhood to avoid cross-pollination. This is called isolation distance.
• Which means that no one within a mile of you can have a flowering B.oleracea plant or you risk cross-pollination/contamination of your seed. 

Ready to give up yet?!

Simplify Kale Seed Saving

I’m going to give you the easiest scenario for you to save kale seed, and then we’ll talk about a few ways to try to overcome challenges.

If you want to save kale seed, it is going to be easiest if you have three parameters:

1. You live in a temperate growing zone without severely cold winters. Growing zones 7-9ish. This will mean that your biennial kale plant can over-winter in the garden without any special treatment and without risk of death due to cold.
2. Or you purposefully select only varieties of kale to grow that have been bred to survive cold winter areas. Growing zones 3-6ish.*
3. You only grow one member of the B.oleracea family at a time for seed saving purposes.

Now, this doesn’t mean that you can’t save kale seed if you live in super cold areas – we’ll talk about ways to make it work.

• I want to emphasize that the most important choice a gardener who lives in a severely cold weather area can make is to ONLY grow kale that has been bred to survive cold winters.

These parameters also don’t mean that you can’t grow other members of the B. oleracea family in your garden at all this year. It only means that you should plan to harvest all the others BEFORE they flower. 

This won’t be hard to do because they’re all biennials, remember? When you’re done harvesting from them in their first year, pull them out of the ground, and feed them to the livestock or compost them.

• Easy peasy and they won’t be in danger of cross-pollinating your kale seed crop next year.

The Other Members of the B. oleracea Family

Here’s a list of “kissing cousins” in this family that you don’t want kissing! No sharing of genetics with your kale seed crop if you want pure kale seed.

• Broccoli
• Brussels Sprouts
• Cabbage
• Collards
• Kohlrabi

According to Seed to Seed, by Suzanne Ashworth, Siberian Kale in the Brassica napus family (to which rapeseed also belongs) is safe from cross-pollination with B. oleracea. My copy of this book was published in 2002, FYI.

Full disclosure, I have yet to grow out B. oleracea variety of kale with a B. napus variety to save seed. I can say that everything I’ve ever read from Ms. Ashworth has been great advice in my seed saving ventures, though. 

Have you ever grown these varieties together for seed saving? I’d love to hear about it!

Growing Your Own Kale in Cold Winter Areas

Most B. oleracea kale grows easily in zones 7-9, with several varieties acclimated to growing in zones as cold as 3-4. (Siberian kale that I mentioned before can go as low as zone 2, from what I’ve read. I live in zone 6, FYI.)

It can withstand the light frosts of fall in all zones, with most varieties tasting even better after a good chill.

If hard frost is expected in zones 3-6, you can do a few things to protect your kale harvest:

• Heavily mulch your kale plants with straw to enable you to protect the last of of the fall harvest of leaves.
• If you want to protect the entire plant for seed saving, create a frame for a low tunnel and cover the kale bed with horticultural plastic.

In zones 5-6, you will most likely be able to harvest kale leaves into the winter. In zones 3-4, it will totally depend on when you get your consistenctly cold weather.

• Kale will go limp when it freezes but once the sun has warmed them, their turgidity will return.

—>>>Click here to read The Ultimate Guide to Growing Kale by Schneider Peeps.<<<—

Severly Cold Winter Areas – Emergency Only Measure

If for some reason you’re worried that despite your best efforts to:

• only select a variety of kale that will survive your winters
• provide winter protection for valuable seed saving plants

will still result in winter damage or death, you may do the following. I warn you, it’s a pain in the butt and you don’t want to have to do it, if you can avoid it.

Dig up your kale plants and bring them inside for winter.

The easiest way to do this is to:

1. Select three of the best kale plants you have prune them back a bit so that no branches will break as you work with them.
2. Pot them up in the late fall. You can also put them in fabric grow bags.
3. Water them well and mulch them with straw or wood chips.
4. If you live in mold-prone areas, consider potting them in sand.
5. Tuck the plants into an insulated garage, store room, or root cellar. 
6. In spring, when all danger of hard frost has passed, set them out to acclimate to the outside weather again.
7. You can keep them in containers or plant them back into the garden to set seed in their second year.

These plants may or may not survive this process and live long enough to set seed, so be ready to try again, if something goes amiss.

Seed saving of biennial plants is not for the faint of heart!

A Little Caveat on Experimentation

Kale is better adapted to cold weather than it is to hot weather, so its a reliable crop for cold seasons. However, each variety will have its own temperature preference.

If you live in a severely cold weather area and you want to save seed and you would like to experiment with leaving your plants in the ground to overwinter, here’s what you can do.

• Be sure you have a low tunnel set up to protect the plants.
• Always heavily mulch them inside the low tunnel. You can also add a layer of horticultural plastic or fabric inside the low tunnel. Every layer you add, increases the heat retained inside.
• Purchase only those varieties of kale that claim to withstand the conditions of your growing zone. These include any Russian or Siberian variety, Blue Scotch, or Lacinto/Dinosaur kale.

Here’s a refresher on understanding planting zones, including climate and micrclimate informatiion.

What About the 1 Mile Isolation Distance?!

Ok, here’s where it’s good to remind yourself that you’re a backyard seed saver and not a botanist. You aren’t growing food in a lab; you’re growing food on your homestead!

The answer to this challenge is that you simply won’t be able to ensure that your neighbors don’t have a B. oleracea plant flowering at the same time as your kale. 

• Take a deep breath, find your center, and let it go.

Sometimes seed saving is a gamble and you simply have to be willing to save some weirdo seeds in amongst the great ones!

Having said that, however, here are some things you can do to reduce contamination in your neighborhood:

1. Invite everyone within a mile to join your new seed saving group! If every gardener around you is seed-saving-conscious, the risk of unwanted cross-pollination is reduced.
2. Having a group also means that you can share the work of seed saving. If you’re saving kale seed this year, the lady down the street can save the tomato seeds, and the gentleman down the other street can save the leek seeds.
3. If you can’t get all the gardeners in your area to join a group, you can at least talk to them a bit about your plans and explain what you’re trying to do. You may discover that no one in the area is as crazy as you are about saving seed and they’ll pull their plants at the end of the growing season.

The only other real option for dealing with this is to cage your seed saving plants and introduce insects into the cage to pollinate. This is something I will probably never, ever, ever do because I’m just not that detail-oriented.

• Incidentally, you can find instructions for caging plants for seed saving online, or Ashworth has instructions in Seed to Seed. Other seed saving books also have this information – go visit the library!

Needless to say, if your homestead garden is very rural and your nearest neighbor is miles away, this issue won’t be a chaalenge for you.

A Little Reminder

I want to repeat that annual plants are SO much easier to save seed from because they complete their life cycle in a grow season.

• Biennial plants like kale are complicated by the fact that it usually requires two years to complete that cycle and set seed.
• They also have wide isolation distances, more so than many other plants.

They’re simply more complicated, even though they’re worth it. So, don’t feel dumb if it’s hard getting started. 

What Kind of Kale Seed to Save?

All the kale varieties create seed in the same way, so you can save seed easily from any of them. The key to choosing the right variety for you lies in determining which features you value most.

• Two of my favorites are Vates and Red Russian kale, from which we harvest leaves throughout the fall and into the winter. 
• Seeds for Generations carries a Lacinato kale that can trace its origins to Tuscany – mangia! Click here to see its seed profile on their site.
• For some notoriety, try growing the walking stick kale featured in the Giant’s Garden section of Sharon Lovejoy’s children’s gardening book, Roots, Boots, Buckets and Shoots. This kale grows several feet tall and has a very straight stem which can, in reality, be turned into a walking stick.

Pick the Mother Plants Carefully

Whichever variety you choose to save seed from this year, these plants will be the mother plants for your kale seed crop. These mother plants are those from which you will be harvesting seed.

The most important criteria for the mother plants are:

1. Choose at least three plants from which to save seeds. More is always better because you will increase the diversity of the genetics in the saved seeds.
2. Only choose those plants that the healthiest, most prolific, hardiest plants in your garden.
3. Only choose those plants that have the other traits that are most important to you like flavor, leaf size, color, etc.

Do NOT choose any kale as your mother plant that is diseased or otherwise undesirable or weak. These should be your absolute best plants.

How to Save Kale Seed

Once the kale plant has gone through a cold weather cycle and the spring weather warms to summer of the plant’s second year, the kale will send up a yellow flowering stalk. These flowers will be pollinated by wind and insects to produce a small, dark, round seed.

All B. oleracea seeds look the same, so be sure you only process one type of seed at a time and label correctly!

How Long from Seed to Seed?

How long kale takes to set seed will depend a lot on your climate. Technically, kale is as a biennial, as we’ve talked about.

However, if you live in a mild winter area, you will probably be able to plant kale in the fall garden and then watch it produce a flower/seed stalk the next summer.

• This is because the trigger for sending up a flower stem is cold weather, aka vernalization. 

Regardless, kale will take up space in the garden longer than something like a head of lettuce. So be sure to plan accordingly.

What Happens When Kale Goes to Seed?

Each plant will send up flowering stalks that can get up to five feet tall. This makes them fun to grow in the children’s garden because the kids can measure the plants’ growth by how tall they themselves are.

• For example, one year my kids went out and determined that the kale stalks measured somewhere between a three and five year old child.

The stalks are very brittle and in high wind will detach from the mother plant. Sadly, this can happen before the seed has time to mature.

• You can’t save immature seed and expect it to be viable. This is true for all seed saving projects!

If you have stalks breaking off, tie them up at their base and at their middle with some garden twine. Use a few small stakes for added support and attach the twine to it.

Once the flower/seed stalks shoot up in the second year, the flavor of the leaves can change. I don’t like to eat it raw at that point, but it’s still yummy in soups.

Regardless, it’s exciting to see the flowers bloom since I know that the seed is coming! 

• One other thing to note is that kale may self-seed in your garden in you live in a mild winter area.
• This means that, if you allow some seed to fall to the ground, you will have baby kale plants germinating in your garden without you having to plant them.

Sometimes they’ll show up in your neighbor’s yard, if the birds or wind get involved.

I love self-seeding plants because I don’t like doing extra work. Just another perk of kale!

The Seed Pods/Seedheads

Kale seed pods start out green, resembling small, skinny green beans. As they mature, they fatten up a bit and start to dry out.

Drying seed pods are a sign that you need to be ready to gather your kale seed soon. You can place a light bag over an entire seed stock or individual seedheads to catch the seed.

• I like to buy those organza gift bags with a drawstring in bulk and place them all over the garden at seed saving time. I always have a stash of those bags shoved unceremoniously in my seed saving boxes because they work for pretty much every kind of seed and seedpod.
• You can also use paper bags if you’re reasonably sure there won’t be precipitation or heavy dew in the next few days.

The seeds will need to be removed from the seedheads, but this is very easy to do with kale.

The Seed Saving Process

1. Once the seed pods ripen, dry out and turn brown, cut the stalks at the bottom of the plant.
2. Invert them into a large paper bag and flail (or bang) the stalks against the side of the bag to dislodge the seeds.
3. Toss the dried stalks into your compost or see if your goats will eat them. (Be prudent with raw Brassicas fed to your ruminants as too much can cause bloat – the dried stalks should be fine.)
4. Start winnowing out the chaff by dumping the contents of your bag either through a screen or onto a sheet.
5. Use your hands to rub the seeds away from the pods.

Kale seeds are small, dark and round. They are usually easy to distinguish in the midst of all the dried out seed casings and aphid corpses that will also be in residence at the bottom of the brown paper bag.

If you’ve bagged your seedheads in the garden, still put them into the paper bag and then remove the organza bags.

• If you open them beforehand, you might loose seed.
• If you flail them in the paper bag, they will most likely get damaged.

Winnowing Options

The word “winnow” means to clean away all the chaff (seed casings and gunk) from your seed. There are many methods you can choose from, but the basic mechanics are the same.

To filter the seeds from the chaff you can use:

• window screen
• fine mesh strainer
• colander
• very loose weave cheese cloth

Really anything that will allow the small seed to fall through, but trap the larger particles of “stuff” will work just fine.

• You can also just dump them onto a white sheet and pick out the seed from the chaff. This is a great project for homeschool or grandkids, by the way.

For more winnowing information:

Winnowing Seed from Homestead Culture

Six Ways to Screen and Winnow Seed from BC Farms and Food

Compost the chaff or toss it back into the garden as mulch. Or, as I mentioned above, you can feed it to livestock or use it as bedding.

A Special Note on Aphids

Aphids can be a nuisance on Brassicas but they don’t usually harm the seed. They can easily be controlled with a strong jet of water from your hose.

• With soft-bodied, plant-killing insects, a few hours away from their food source and they die. 

Even if you harvest your seed stocks with a few aphids, they wont live long enough to do any damage to the seed, even if they could.

During the growing season, if cabbage root maggots are a problem in your area, you can use floating row covers to protect your kale crop. Be sure to remove them before flowering, though.

Learn more garden tricks and keep great notes on your garden each year with The Gardening Journal – just click below to learn more.

–>> Pin This Article for Later <<–