How to Save Onion Seeds


Onion seeds are easy to collect and store. Unfortunately, onions are a biennial plant, which means that they can only be harvested once every 2 years.[1] Before you abandon all of your recipes involving onions, take a moment to plan out your gardening schedule. By preserving your onion seeds after each harvest, you’ll have no shortage of future onions to satisfy all of your culinary needs!

Part 1
Harvesting the Seeds

Harvesting the Seeds on How to Save Onion Seeds

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Monitor your onion plants as they grow, and wait for the seed heads to appear. They’ll resemble large dandelions, and physically look like a clump of small white flowers. Once the flowers begin to bloom and dry out, small, dark seeds will fall out of the flower buds and into the surrounding soil.[2] The onion seeds will be ready to harvest around late summer, when the weather is still warm.[3] Onion seeds are about the size of pebbles. Don’t worry if you can’t see them right away, as they might blend in with the soil. Dried flowers will look brown instead of white. You’ll also be able to see the dark seeds inside of the buds after the flowers start opening.[4]

Harvesting the Seeds on How to Save Onion Seeds

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Wait for the flowers to completely dry out before going to check the nearby soil. Use your fingers to pinch and pluck the seeds out of the soil. If you’d like to grab more seeds at once, consider using a small gardening trowel.[5]If you want to keep your hands from getting especially dirty, wear gloves when you’re collecting the seeds.

Harvesting the Seeds on How to Save Onion Seeds

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Get more seeds by snipping off especially dried flowers. Shake these dried buds over your seed collecting container if you’d like to get these seeds right away, or keep the buds in the container to sort through later.[6]A large bowl or plastic bin work well for this.

Harvesting the Seeds on How to Save Onion Seeds

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Pick up a bunch of seeds from different onion plants. If you’re an avid gardener, you might have more than one kind of onion genus planted in your garden. [7] Having a variety of seeds collected makes it easier to plant a more diverse, high quality garden in the coming months. For example, if you live in a place with a lot of sunlight (i.e, northern Canada), try planting Yellow Sweet Spanish or Red Wethersfield onions. If you live in a warmer place, consider growing White Bermuda or Burgundy onions instead.[8]

Harvesting the Seeds on How to Save Onion Seeds

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Place all of your collected seeds in a basket or container. Set this on a flat surface, and begin picking through the menagerie of seeds. Your goal is to remove any stems, flower buds, or decidedly non-seed items from the rest of the pile. Once you’ve done this, your collection of onion seeds will be ready for drying and storage.[9] Keep different types of onion seeds in different baskets and piles to help keep your garden organized in the future. If the flowers haven’t started to open yet, let the seed collection bowl sit in a cool, dark area until the buds dry out. Once the flowers start drying out, you can rub them with your fingers to force the seeds out more quickly.[10]

Part 2
Drying and Storing the Seeds

Drying and Storing the Seeds on How to Save Onion Seeds

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Figure out what the coolest, driest place in your house is before getting the seeds ready for storage. In order to keep your onion seeds as fresh as possible, they need to be kept away from heat and sunlight. Locations like a cellar or pantry are great places to consider, as long as they aren’t well-lit throughout the day.[11]Don’t worry if your cellar or pantry isn’t completely dark—you only need a small, dark section of space to store your onion seed container.

Drying and Storing the Seeds on How to Save Onion Seeds

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Spread a towel over a flat surface and pour the seeds onto it in a single, even layer. Level out the seeds so that none of them are stacked on top of one another. If they’re layered in any way, it will take significantly longer for them to dry out completely.

Drying and Storing the Seeds on How to Save Onion Seeds

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Let the seeds air-dry for a few days to remove any excess moisture. While they probably won’t be that moist to begin with, this process ensures that the seeds will be as dry as possible when you store them. If they’re kept dry, they’ll be fresher and better to use when the next planting season comes.[12]

Drying and Storing the Seeds on How to Save Onion Seeds

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Pour the dried seeds into a small, airtight container for long-term storage. Place the container at the edge of the towel and use your hand to slide the seeds into the container. Seal the container as tightly as possible to ensure that no air gets in. This will keep the seeds as fresh as possible.[13]

Drying and Storing the Seeds on How to Save Onion Seeds

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Set the container of onion seeds in a dark, cool place for the time being. Since onions can only be harvested once every 2 years, the seeds will also have to be used and planted within that time period. They won’t stay fresh if you keep them stored for a longer period of time, so be sure to have a planting schedule in mind![14]If you time your harvests right, you can ensure that your cellar is always stocked with onion seeds.

Part 3
Planting the Dried Seeds

Planting the Dried Seeds on How to Save Onion Seeds

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Ready the seeds by filling a small, shoebox-sized container halfway with pre-fertilized soil. Plant each seed so that they’re at least 0.25 inches (0.64 cm) apart. Keep the container of planted seeds outside and away from the sun. Do this in mid to late autumn.[15] Don’t worry about the winter weather—the seeds will be fine as long as they’re kept in the plastic box. Cut at least 2 0.5 inches (1.3 cm) holes on the lid and bottom of the plastic box to ensure that the seeds get enough air.

Planting the Dried Seeds on How to Save Onion Seeds

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Opt for an indoor garden by burying the onion seeds 0.25 inches (0.64 cm) apart in a bed of fertilized soil in a small planter. Keep this container under a set of indoor gardening lights. Schedule the lights to turn on and off automatically, and make sure that they aren’t on for more than 12 hours each day. This process can be started at the beginning of the year, or at least 3 months before you plan on planting the seeds outside during springtime.[16]Avoid growing onion seeds indoors with other vegetables, as those plants might require more than 12 hours of sunlight.

Planting the Dried Seeds on How to Save Onion Seeds

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25 inches (0.64 cm) deep in the soil. Make sure that each only seed is buried just beneath the surface of the dirt. Regardless of the method you’re using, aim for the onions to be as close to the surface as possible when they sprout. In the case of onion harvesting, a little tends to go a long way.[17]If you’re using indoor lights to grow your onions, be sure to plant them outside once spring arrives.[18]

Planting the Dried Seeds on How to Save Onion Seeds

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Keep the biennial onion schedule in mind when planning your harvests. While onions are most ready to harvest in late summer, each crop only yields a harvest once every 2 years. Because of this, try planting a new crop of onions each year, so you always have vegetables and seeds to harvest come when summer ends.[19]Once you have a planting cycle, you’ll be able to save your onion seeds like clockwork!