How do You Get Seeds from Kale?

You get seeds from kale by letting a plant live through winter, flower in its second spring, and produce seed pods. Once those pods turn brown and dry, you collect them, crush the pods, and separate the small round seeds from the chaff. Saving your own kale seeds is simple, saves money, and ensures you have a steady supply of your favorite variety for seasons to come.

What Is the Best Kale Variety for Seed Saving?

Kale is a biennial — it grows leaves in its first year, then flowers and sets seed in its second year. For reliable seed saving, start with open-pollinated or heirloom varieties. Varieties like 'Lacinato' (also called Dinosaur kale), 'Dwarf Siberian', 'Red Russian', and 'Vates Blue Curled' are excellent choices. They produce seeds that grow into plants identical to the parent.

Hybrid varieties (marked F1) will not come true from seed. If you try to save seeds from a hybrid, the next generation may be small, bitter, or misshapen. Stick with open-pollinated types for consistent results.

Can You Save Seeds from Any Kale Plant?

You can technically save seeds from any kale plant that flowers, but the quality depends on the plant's health and genetics. Choose your strongest, healthiest plants — the ones that resisted pests, survived cold, and produced tasty leaves. This way you pass those good traits forward. Avoid plants that bolted early in their first year (that's a sign of stress) or showed signs of disease.

When Should You Let Kale Go to Seed?

Kale needs a cold period (vernalization) to trigger flowering. In most climates, you plant kale in spring or late summer for leaf harvest, then let it overwinter in the garden. The following spring, as temperatures warm and days lengthen, the plant sends up a tall flower stalk — this is called bolting.

The timeline usually goes like this:

• Year 1, spring – Plant kale from seed or transplants.
• Year 1, fall-winter – Harvest leaves until hard frost; mulch the plant heavily or cover with row cloth in colder zones.
• Year 2, late spring – The plant bolts and flowers (usually May to June).
• Year 2, mid-to-late summer – Seed pods mature and dry. Harvest in July or August.

If you live in a very mild climate (USDA zones 8–10), kale may not need a true winter to bolt — it may flower after a prolonged cool period. But for most gardeners, a real winter is required.

How Do You Prepare Kale Plants for Seed Production?

Select two or three of your best plants early in the first year. Keep them for seed production and do not harvest leaves from them after a certain point. Remove any weak or off-type plants so they don't cross.

Overwintering Tips

In spring, remove any damaged leaves and let the stalk grow. You may need to stake the flower stalk if it becomes top-heavy. The plant will produce clusters of yellow, four-petaled flowers — these attract bees and other pollinators.

Isolation Matters

Kale belongs to the Brassica oleracea species, which also includes cabbage, broccoli, Brussels sprouts, cauliflower, and collards. These plants can cross-pollinate with each other. If you want pure kale seeds, keep your kale seed plants at least 800 feet away from any flowering brassicas, or use row covers and hand-pollinate. Otherwise, your saved seeds may produce unpredictable hybrids. For a home gardener, a small amount of cross-pollination often goes unnoticed, but for accurate traits, isolation is important.

How to Harvest Kale Seed Pods?

After the flowers fade, the plant forms narrow, pointed seed pods (siliques). Each pod contains a row of small round seeds. The pods turn from green to brown and become dry and brittle. Harvest when the pods are brown and the seeds rattle inside.

Step-by-Step Harvest

1. Check the plants every few days once the lower pods start turning brown. Pods can shatter quickly and spill seeds.
2. Cut the entire stalk or branches of pods using garden shears. Work in the morning when dew is present — pods are less likely to split open.
3. Place the cut stalks into a large paper bag or on a clean tarp. Label the bag with the variety and date.
4. Bring the stalks indoors to finish drying if the weather is humid. Leave them in a warm, well-ventilated area for 1–2 weeks until pods are completely crisp.

Do not wait until all pods on a plant are brown — the first ones to dry will shatter and lose seeds. It's better to harvest in stages or cut the whole stalk when the majority of pods are brown.

If you need a tool to gather seed heads, consider a set of seed drying bags or a simple paper lunch bag to catch loose seeds.

How Do You Thresh and Winnow Kale Seeds?

Threshing means separating the seeds from the pods. Winnowing means removing the light chaff (pod pieces, stems, dust) from the heavy seeds.

Threshing Methods

• Hand rubbing: Place dry pods in a bowl, rub them between your palms, and break them open. The seeds fall out easily.
• Grain bag method: Put pods in a heavy canvas bag and walk on it or beat it with a wooden paddle.
• Screen method: Rub pods over a mesh screen with holes just smaller than the seeds. The seeds fall through, and chaff stays on top.

Winnowing Methods

1. Pour the threshed mixture into a shallow bowl or tray.
2. In a gentle breeze or in front of a fan on low, slowly pour the mixture from one container to another. The wind blows away the light chaff while the heavier seeds drop straight down.
3. Repeat 2–3 times until the seeds are clean.

A simple fine-mesh strainer can help separate tiny seed fragments from the seeds. You can also use a screen with 1/16-inch holes.

How Do You Store Kale Seeds for Next Year?

Proper storage keeps kale seeds viable for 3 to 5 years or longer. Follow these steps:

1. Dry further: Spread the cleaned seeds on a plate or paper towel for another week at room temperature. They should break when you bite one, not bend.
2. Package: Place seeds in a paper envelope or a glass jar. Write the variety, harvest year, and any notes.
3. Store in a cool, dark, dry place. A refrigerator (not freezer) works well if airtight. Use a desiccant packet like silica gel packs to absorb moisture.
4. Avoid moisture and light — both shorten seed life.

If you plan to share or trade seeds, use small coin envelopes.

Common Mistakes When Saving Kale Seeds

• Harvesting too early. Pods that are still green or tan may not have fully developed seeds. Wait until they are brown and dry.
• Harvesting too late. Pods shatter quickly. Check daily once the first pods turn brown.
• Not isolating from other brassicas. Cross-pollination leads to strange-looking kale offspring. If you don't care about purity, ignore this.
• Skipping the drying step before storage. Trapped moisture causes mold and rot.
• Storing in a warm kitchen or garage. Heat and humidity kill seed viability.
• Using only one plant. Saving seeds from multiple plants preserves genetic diversity and reduces inbreeding. Use at least 5–10 plants for long-term seed saving.

How Many Kale Seeds Does One Plant Produce?

A single healthy kale seed plant can produce hundreds to thousands of seeds. You can easily harvest 2–4 tablespoons (roughly 300–600 seeds) from one plant. With three plants, you’ll have more seed than you can use in a season — perfect for sharing with friends or planting a larger patch next year.

Frequently Asked Questions About Saving Kale Seeds

Do I need to let kale flower to get seeds?
Yes. In its second year, the plant sends up a flower stalk. If you harvest leaves heavily, you may delay or reduce flower production, but the plant will still eventually bolt and set seed.

Can I get seeds from store-bought kale?
Grocery store kale is harvested before it flowers, so it won't produce seeds. You'd need to plant a root crown or buy a seedling and let it overwinter.

How long do kale seeds stay viable?
Properly stored kale seeds remain viable for 3–5 years. After that, germination drops significantly.

What do kale seeds look like?
Kale seeds are small (about 2 mm), round, and dark brown to black. They look similar to black mustard seeds or tiny peppercorns.

Can I plant kale seeds directly in the ground?
Yes. Plant them ¼ to ½ inch deep, water well, and keep soil moist. They germinate in 5–10 days in cool soil (60–70°F).

Getting Seeds from Kale: Why It’s Worth the Effort

Saving your own kale seeds connects you to the full life cycle of the plant and builds resilience in your garden. You get a free, tailored seed supply, you preserve rare varieties, and you avoid buying new packets every year. The process is straightforward: choose a healthy open-pollinated variety, overwinter a few plants, wait for the second-year flower stalk, harvest dry pods, thresh, winnow, and store. With careful handling and proper storage, those tiny seeds will fuel your kale patch for years.

Start with one or two plants this season. By this time next summer, you’ll have your first home-saved kale seeds — and the confidence to save seeds from other garden crops too.