Collecting, Curing and Storing Garden Seeds

Gardeners first discovered the wonders of seed stewardship 12,000 years ago, and we’ve been saving and replanting our best seeds ever since. We have several great articles on growing seeds for seed saving including Seed Saving for Food Security, which covers crucial guidance for preserving valuable plant genetics. But some of the fine points of collecting, curing and storing garden seeds still need clarification.

Collecting Seeds for Saving

In a perfect world, seeds are allowed to stay on the mother plant until they are completely ripe, but this is not always practical. Perhaps prolonged wet weather is expected, or you need the space for something else, or cold, dim days have stopped plant growth. In these situations, it is always best to gather seeds and let them finish ripening and curing indoors, where fewer hazards await them. If necessary, you can pull up plants whole and hang them in a dry place to give seeds extra time to finish.

For stemmy plants that hold their seeds on brittle branches like rocket, parsley and coriander, I collect the seeds on a dry day by cutting the branches and placing them in a broad bowl. After a couple of weeks, it’s easy to crunch through the dried stems with your hand, which releases the seeds so they fall to the bottom of the bowl.

Open air speeds the drying of pepper seeds, too, but after a few days all shrivelled pepper hearts look alike. To prevent confusion, I dry peppers and other seeds in paper cupcake liners labelled with variety name. For larger items like beans or flower heads, I use open paper bags placed in a dry, airy space, each one labelled with its contents.

Cleaning Saved Seeds

After collected seeds have dried indoors for a few weeks, you must separate them out before storing them for the winter. Large seeds like beans, cucumbers and squash can be cleaned by hand and then air dried at room temperature for a couple of weeks. I like to place them in bowls so I can stir them with my fingers every few days for even drying, plucking out small or misshapen seeds when I spot them. Only the biggest and best seeds should be replanted.

With basil and other plants that set only a few seeds on each branch, it is often easiest to crush the dry plant material onto a plate and pick out the seeds with your fingers and set them aside. With more generous seed producers, I use screens made from fabric netting mounted in embroidery hoops to separate seeds from plant debris. From there you can try winnowing out the remaining chaff with a small fan or hair dryer, but this is not always practical, especially with seeds that have points or wings. I have better luck working with gravity, by placing the seeds in a large pan and shaking it gently while holding it diagonally. Round seeds will roll toward the bottom, where they are easily collected. Flat, heavy seeds will tend to stay put.

As a gardener rather than a seed company, it is not required that you remove every bit of plant material before storing your seeds. A few pieces of stem or seed pod won’t hurt as long as they are bone dry.

Storing Garden Seeds

Beans and other large seeds can be stored in small jars with airtight caps, but most of my small seeds go into labelled paper envelopes rescued from the junk mail pile, cut in half and securely taped shut. I especially like window envelopes because you can see the seeds inside. Again, labelling with the plant name and year is essential, because the human brain is ridiculously fallible.

For more than a decade I have stored my seeds in a plastic snap-top bin, kept in a cool, dark closet. I use desiccant packets saved from shoes and other packaged goods to reduce humidity in the box, so both temperature and moisture content stay steady. This is the most important aspect of seed storage. Whether you use a cool closet or your freezer, it’s the constancy of conditions that counts.

I organise my seeds by plant type (roots, leafy greens, cabbage family, herbs, flowers) but some people sort their seeds seasonally, or even by month. Choose a system that helps you find seeds quickly, and is easy to keep in order. Being a seed steward is important work, so why not spend some time with it? When seeds were in short supply earlier this year, my stockpile helped fill out several neighbours’ gardens as I passed on the generosity of plants.