Everything You Ever Wanted To Know About Seed-Saving

Well, maybe not everything. That would take a book (and there are many good ones). But, we’ll get you started down the path. 

Why People Save Seeds

Our ancestors saved seeds. While we may not think much about seeds being available now (check out our nifty catalog!), a few generations ago, you saved seeds, bartered for some with a person who did, or you went without. Even farmers saved seeds from this year’s crop to plant next year. 

Now, we save seeds to preserve a particularly successful strain in our garden, to experiment with breeding new varieties, or just for the fun of it. Saving seeds from a favorite plant and regrowing it the next year is a full-circle experience. 

Differences Between Flowers and Vegetables

Saving most flower seeds is easy to figure out. The seed head for a coneflower (Echinacea) is obvious, and the seeds are visible as they mature. It’s a matter of beating the finches to them, and the seeds are ready for saving right off the plant. Many vegetables, like tomatoes, for example, have hidden their seeds inside a fruit and will require some processing to be ready for storage. 

Some vegetables we grow–and some flowers–are biennials, meaning they won’t set seed their first growing season. Carrots, for example, are normally harvested during the first year for their tasty roots. To save carrot seeds, you’ll need to leave a few carrots in the garden over winter so they can flower and set seed the next year. If you’ve had kale–another biennial–survive the winter and allowed it to remain in the garden, you may have noticed it flower and make seed heads the second summer. 

Hybrids and Open-pollination (and cross-pollination)

When you buy seeds, you’re choosing a plant variety that is either a hybrid or open-pollinated. A hybrid is a cross between two parent plants with desirable characteristics. It could be for flower color, disease resistance, or any other trait. When seeds from hybrids are saved, the next generation of plants will not be true–some traits will revert to the original parents. A hybrid flower may revert to a different color, or a vegetable plant might change in growth form or disease resistance. 

For seed saving, choose non-hybrid varieties (open-pollinated) that will pass their traits down true to variety. Open-pollinated simply means that in the absence of a cross-pollination problem (more on that in a second), the seeds will produce daughter plants with the same characteristics as their parents. Some of these open-pollinated varieties have been popular for so long that they’ve become “heirloom” varieties. 

Cross-pollination occurs when two plants of the same species but different varieties exchange genetic material. It affects the seeds and eventually the next year’s fruit, but not this season’s crop. A pumpkin and a squash cross-pollinating won’t yield strangely shaped pumpkins or funky-colored squash this year, but next year’s results may be different. For crops where we eat the seeds, like sweet corn, the difference is noticeable in the first year. It’s why sweet corn grown near field corn can be less sweet and more starchy if they tassel at the same time. 

When Are the Seeds Ready for Saving?

Flower seeds are usually easier to gage. Look for the flower head to be withered and spent–the petals will have fallen off–and the remaining head may turn brown. Individual species vary, so you’ll need to keep a close watch. While some, like sunflowers, will hold onto their seeds for quite a long while, others will burst their seed heads and scatter them. Smaller seeds will blow away in the wind if not gathered in time. 

Some vegetables are ready for the table long before the seeds are ready to be saved. A snap pea, for example, is eaten when the seeds (the peas in the pod) are not yet mature. The same goes for fresh green beans. To save pea or bean seeds, we need the pod to mature and dry, allowing the seeds inside to get hard. 

We eat sweet corn when it’s tender and juicy, but to save the seeds leave the ears on the plant until the husks are brittle and the kernels are dry and hard. A tomato seed is mature when the fruit is ready to eat, but a cucumber should grow large and start to yellow before the seeds are ready. If in doubt, a quick internet search about saving seeds from that particular vegetable will provide the answer.

Harvesting, Cleaning, and Storing Seeds

Collecting some flower seeds requires little more than an envelope and a pencil to label them. Marigold seeds can be easily rubbed off the seed head into an envelope and sealed, ready for spring. Many flower seeds can be left to dry on the plant, or the entire head can be snipped and brought indoors to process. Either way, allow the seeds to fully ripen on the flower head before separating them. 

Most flower seeds come with some chaff, which you’ll want to sift off before storage. Gently rubbing the collected seed material between your palms will often do the trick. Winnowing is the word for using wind or moving air to help clean seed (or grain). It’s easy to do with a light breeze or a small fan set on low and is best done outside. To remove the chaff, stand outdoors in the wind or in front of the fan and gently pour the gathered seeds and chaff from one bowl to another. Experiment with the height of the upper bowl until the chaff blows away, but the seeds still drop into the bottom bowl. 

For wetter seeds like tomatoes, pumpkins, or peppers, separate the seeds from the pulp. Wash these seeds in warm water, using your fingers to work most of the pulp away from the seeds. Once they are cleaned, you’ll need to lay them out to dry before storing. For home gardeners, the seeds should be clean, but they don’t have to be perfect. The cleaner the seeds, the better, but don’t lose sleep over it. Proper drying, however, is immensely important. 

Seeds store best in cool, dark, dry conditions. A closet along an outer wall or a basement shelf is a good start. Keep them out of direct sunlight and moisture-free. Envelops, custom seed saving packets, or even clean jars with lids work fine.

Label every container! Start saving seeds and you’ll be amazed at how similar some look. Don’t assume you’ll remember which variety was in that pretty jar with the flowered pattern on the lid come spring. Plant-and-find-out isn’t the best way to keep track of which seeds are which.

How to Conduct a Germination Test

Like me, you may wonder if that batch of seeds in the envelope is still good. Did I do it right? Did I harvest them when they were ready, or did I jump the gun? Did they get properly pollinated? One way to check on the viability of your seed before you potentially waste garden space and time in spring with duds is a germination test. It’s pretty simple. 

To conduct a seed germination test, you’ll need:

• A wet paper towel or coffee filter
• A clear, sealable plastic bag
• 10 seeds (if you have them to spare–five can serve if you’re short)
• A warm spot
• Time

Sprinkle the seeds on your wet paper towel, fold it in half, and stick it in a clear plastic zip-top bag. Check the bag every 3-4 days, keeping the towel moist and checking for sprouts. Be sure to give them enough time; some seeds need 2-3 weeks to germinate, while others will pop in a week or less.

If your seeds sprouted, count the number of successes and divide that by the total number of seeds in the test, then multiply by 100 to find your germination rate as a percent. 

Example: four of five seeds sprouted. Therefore, 4÷5 = 0.8   Multiply 0.8 x 100 = 80% germination rate. 

If your seed viability was less than 80%, you can use that number to help you plan for reduced germination in spring. For example, if you want 20 tomatoes, but your seed viability is 60%, divide 20 by 60%, and you’ll know to plant 33 or 34 seeds to get 20 seedlings sprouted. 

A germination test is also handy for older seeds to ensure they haven’t expired in storage. While some seeds can be stored for years in the right conditions, others last only a season or two before their potency falls off significantly.