How to Store Leftover Seeds from the Summer Garden

by Daniel J. Leonard | Jul 23, 2020

I enjoy starting my garden from seeds.  Ordering seed opens so many more options relative to the limited old-fashioned seed and transplant selections that line garden shelves. Picking newer, improved varieties has several other advantages as well, including increased disease resistance, earlier fruiting, unusually colored/shaped fruit, and generally more vigorous plants.  One of the most exciting days of the year in my house is when the cardboard box full of the season’s seed packets comes in the mail!  However, I garden exclusively in small, 4’x8’ raised beds and only need a couple of plants of each veggie variety to fill the fridge with fruit; meaning I always have leftover seeds in the packets!  In the past, I’ve thrown the excess seed away and chalked it up to the cost of gardening in small spaces, but this spring, as seeds became somewhat hard to come by and several of the varieties I normally grow were out of stock, I started saving and storing my leftover seed packets for future seasons to ensure I have what I want!  You can save and store seeds too, here’s how.

Cauliflower seed waiting for the fall garden in the author’s refrigerator.

Properly storing your leftover seeds is a relatively simple process.  While seed longevity definitely varies somewhat according to species, regardless of how they are treated by you, remembering the following few tips can help improve the stored seeds’ viability and vigor for the next season.

• Store Cool. Seeds like to be stored in a refrigerator around 40 degrees F.  Seeds stored warmer, near room temperature, or colder, as in a freezer, will decline much more rapidly than those in the fridge.
• Keep it Dry. Humidity or moisture in the seed storage area is a sure way to reduce the shelf life of seeds.  Store dry in plastic bags or glass containers and add a dessicant.  Dessicants help keep storage containers dry and can be found for around $1 each from various online purveyors, making them a cheap insurance policy for your home seed bank!
• Don’t Store Pelleted Seed. These days, you can buy pelleted seed for many of the smaller seeded vegetable varieties, like lettuce and carrots.  The pelleting process and materials used, while making it easier for old eyes and those of us with fumbling fingers to plant, reduces seed longevity.  Do your best to plant all the pelleted seed you purchase.  If you store pelleted seed, don’t say you weren’t warned when next season’s germination is poor!
• Plant All Stored Seed the Next Season if Possible. Remember, that while most non-pelleted vegetable species’ seed can remain viable in storage for more than a year, it’s best to only store seeds until the next season and use them up.  Regardless of how well you store them, seed germination percentage (how many in the lot will sprout when planted) and vigor (how strong the germinating seedlings are) decline in direct proportion to time spent in storage.
• Plant Old Seed Heavy. As germination rates in storage may have declined, it’s best to plant stored seed a little thicker than you normally might.  If you need a squash plant in a certain spot, instead of just planting one seed, put three or four in the hole to ensure you get a plant.  You can always thin extras later, but time lost replanting cannot be regained.

By following these few simple tips, you can waste a lot less seed and ensure that you have what you want to plant for the following year!  As always, if you have any questions about saving and storing seed or any other agriculture or horticultural topic, please contact us at the UF/IFAS Calhoun County Extension Office.  Happy Gardening!

The following resources were used as references when writing this piece and may prove helpful to you also, check them out:

• Johnny’s Selected Seeds Seed Storage Guide:  https://www.johnnyseeds.com/growers-library/tools-supplies/seed-storage-guide.html
• Seeding the Garden EDIS Publication: https://edis.ifas.ufl.edu/vh026#:~:text=Storing%20Leftover%20Seeds,better%20than%20in%20the%20refrigerator.