Seed Saving: How to Save Broccoli Seeds

Learn exactly how to save broccoli seeds for next year, and you’ll never have to buy them again!

Broccoli is part of the cabbage family, also known as the “brassicas”. It is closely related to cabbage, cauliflower, European kale, kohlrabi, collards and Brussels sprouts.

This cold hardy biennial is one of the easiest cabbage family members to save seeds from!

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How to Save Broccoli Seeds

1. To save broccoli seeds, choose an open pollinated variety
2. Allow at least 6 plants to bolt and flower for good pollination
3. Isolate broccoli by caging or by 1/2 mile distance from related plants, which include cauliflower, cabbage, European kale, Brussels Sprouts, kohlrabi and collards.
4. Harvest the seed pods when they are dry and brown

To save broccoli seeds, you’ll want to find an open-pollinated variety (“OP”) you like, and not a hybrid (“F1”). Many broccoli cultivars are hybrids, which sometimes grow faster, but will give you mixed results if you save seeds from them. Some of the resulting plants may look nothing like what you started with. You can read more about saving seeds from hybrids here.

Some good open pollinated broccoli varieties include Thompson, Calabrese and De Cicco. If the broccoli is marked “heirloom”, that means that it is open pollinated and a suitable variety to save broccoli seeds from! You can find open pollinated broccoli seeds from Baker Creek.

You’ll also want to grow at least 6 plants for seed to ensure good pollination. 20 or more plants is ideal to prevent inbreeding.

Where Do Broccoli Seeds Come From?

So where exactly do broccoli seeds come from? The florets we eat are actually the flower buds. Normally, broccoli is cut before it has a chance to flower, but to save broccoli seeds you’ll have to let your plants bolt!

So can you eat your broccoli and get seeds too?

Sorta.

Obviously any buds you eat will not make flowers and go to seed, but most varieties produce side shoots, so it’s totally okay to eat the main head and leave the smaller side shoots to produce seeds.

Just remember to let at least 6 plants go to seed for good pollination!

Tip: If you can get your broccoli to head up, it should go to seed with no problem. But in some climates it can be harder to get your broccoli to even form heads. As a biennial, broccoli likes to go through a period of vernilization, aka winter, before heading up. Try planting at a time of year when the broccoli will be exposed to low temperatures around 25-28 degrees Fahrenheit, following by a warm spell.

In the north, it works well to plant it as a spring crop, so it is exposed to cold temperatures and heads up in early summer. Gardeners in the south may have better luck planting broccoli in the fall and letting it go through winter. It will produce seed the following spring or summer.

Broccoli Pollination

To save broccoli seeds, it’s important to be aware of the other types of plants broccoli can cross with.

Broccoli plants allowed to bolt will soon blossom into a tall stalk covered in small yellow flowers. Pollinated by insects, broccoli can cross with other varieties flowering within 1/2 mile or more (it doesn’t matter if other varieties are grown closer if they  are not allowed to flower). Commercial growers and serious seed savers use a technique called caging to keep different varieties from crossing with each other.

Since they are the same species, broccoli will readily cross with other Brassicas, including European kale (not true Siberian kale), kohlrabi, cauliflower, cabbage (not Chinese cabbage), Brussels sprouts and collards if they are in flower at the same time. The same rules for isolation distance or caging apply with these related plants.

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Saving Broccoli Seeds

After flowering, the flowers will give way to skinny green pods 2-4″ long. The seeds are ripe when these pods dry and turn light brown.

To save broccoli seeds, cut the stalks when the seed pods are mostly dry. Waiting too long can result in the pods breaking open in the garden.

Place the stalks upside down over a box or spread them out on a tarp in a covered area to finish drying. When the seeds are completely dry, lightly tapping the plant against a hard surface will easily release them.

Let the seeds dry in an airy place for a few more days before storage. Broccoli seeds, properly stored, can last 5-8 years. You can find out more about seed storage here!

Want to learn more about saving seeds? Check out our seed saving course! Our course will teach you everything you need to know to save seeds from your garden in just a couple hours’ time!

Happy Seed Saving!