How to Save + Store Seeds
Tips from a Master Gardener
The Fall landscape is filled with spent plants, drying up and dropping their seeds. Whether we’re roaming the wild or walking through a garden, this is a season to harvest seeds. It’s a simple process, and like most tasks in the garden, quite meditative as well. It’s a favorite seasonal ritual of mine. What’s more, the joy of sharing home-grown and hand-packeted seeds from my garden with friends near and far is an opportunity not to be missed. This act of reciprocity is just one of the many ways gardeners have shared stories, their joys in nature, and delicious harvests from one home to another through the generations. Saving seeds is straight forward, but there is some important background knowledge an experienced gardener should wield. Here’s a lesson answering all of your seed saving questions and providing you with my master gardener seed-saving tips.
The wildflower meadow in September
Before diving into how to save seeds, it’s important to understand what types of seeds can be saved, as well as basic plant and seed terminology.
Important Seed Terminology
Self-pollinating: Plants pollinate themselves without help from insects or other plants. Each flower contains both the male and female reproductive organs which enables this to happen. Beans, peas, and tomatoes, are a few examples of self-pollinating plants that are great for beginner seed-savers.
Open-pollinated: Plants pollinated in the field by insects, animals, wind, rain, etc. Plants, such as pumpkins, squash, cucumbers, and corn, will cross-pollinate, meaning the seeds from one variety can be affected by pollen from a neighboring plant. If you are growing more than one type of open-pollinated plant within the same plant family (i.e. two different varieties of squash) near each other, and you save seeds from the resulting fruit, remember that they may have been cross-pollinated. The offspring plant will contain genetics from both parent plants, creating a hybrid.
Hybrid plants: Do not save seeds from hybrid plants. Hybrid plants are two varieties that have been cross-pollinated to produce a third variety with desired traits from the “parents.” Oftentimes hybrid plants are intentionally bred for disease resistance, a certain color flower, or a specific flavor or texture of fruit. Seeds saved and planted from hybrid plants will not grow to be “true to type.” This means that the seeds will not grow into a plant that is the same as the plant you harvested from. Fruit will be very low-quality, flower characteristics will sub-par, and you won't be able to predict what traits will arise. If you grew a hybrid plant from a seed supplier or nursery and you want to grow the same plant again, you’ll need to purchase the seeds or the plant from a supplier that is intentionally breeding that variety.
Heirloom seeds: Most heirloom varieties are good choices for saving. The seed has been handed down for 50 years or more and the resulting traits of the plant are desirable and predictable. It’s also a beautiful tradition between gardeners and generations to save and share seeds containing rich history.
Slide from the Beginner Gardener Course
Plant Lifecycle Types
As it relates to seed saving, there are three plant life cycle types that it determine when it’s time to harvest.
Annual: plant life cycle lasts 1 year, then it dies.
Biennial: plant life cycle lasts 2 years, then it dies. It will get established and leafy the first year, then bloom and seed the second year.
Perennial: plant life cycles lasts 2+ years. Instead of dying at the end of the growing season, the energy and plant sugars travel to the roots while the foliage dies off. It goes dormant, then awakens when the next growing season begins.
Slide from the Beginner Gardener Course
When is the best time to save seeds?
Seed harvest timing depends on the plant type and their life cycle. The best time to harvest seeds is after the plant has bloomed or fruited and the seed pods have fully developed. This is right before, or during, the death + dormancy phase. Look for seed pods that are completely dry on the plant, or starting to drop to the ground. Fruit is simply a fleshy and protective seed pod. Considering plants that produce a fleshy fruit with seeds in it, such as tomatoes, the best time to harvest is when the fruit is most ripe, because the seeds will be fully formed in their “seed pod”. Some plants fruit and go to seed in spring or summer. Most often though, autumn is the best time to harvest seeds because many plants are nearing the end of their seasonal lifecycle.
How to Save Seeds
How to Save Dry Seeds
When seed pods completely dry and turn brown on the plant, cut off the stem or pluck the seeds by hand.
Gather seeds into a solid container such as a bucket, harvest tray, or paper bag.
If the seeds are in a pod or protective layer, remove them. This can usually be done by breaking the seed pod with your finger tips, or shaking the pod to let the seeds spill out.
Separate seeds from chaff (the tiny bits of dead plant material). This is optional, but makes it easier to see exactly how many seeds you’ve harvested. This can be done by hand picking the seeds out, but this can be tedious. Seeds are usually denser than the chaff, so here’s an easy fix:
Outside, lay down a tarp under a bucket. With the seeds and chaff in a cup, stand over the bucket and pour the seeds into the bucket. A gentle breeze will blow the chaff away. The tarp will catch any stray seeds.
How to Save Wet Seeds
Wet seeds, such as tomato and cucumber seeds, need to be fermented to remove pulp and the protective layer that surrounds each seed in the fruit.
Cut the fruit in half and scrape the seeds into a glass jar and add water.
As the seeds ferment, the pulp falls away from the viable seeds. Stir to prevent mold forming.
Once the seeds have fermented, add water to the mixture and mix. The viable seeds will sink to the bottom and the pulp will remain at the surface of the water. Pour off pulp. Repeat until the water is clear.
Drain into a sieve and rinse with water. Seeds should feel rough, not slippery.
Spread them out on coffee filters. Allow the seeds to completely dry; 1-2 days.
*Wet seeds that do not need fermentation include melon, eggplant & ground cherry. Remove seeds from the fruit and wash them under running water.
Master Gardener Seed Saving Tips:
Lay down a tarp around the harvest site in the garden to catch seeds as you harvest.
Process seeds on a table, over a solid plate and a place mat or table cloth to catch seeds.
Save seeds from only the best plants and fruit. Do not save seeds from diseased fruit or plants. When you save seeds, you select which traits you want to continue.
How to Store Seeds
Let seeds fully dry before storing. It helps to let them sit out to air dry for 1-2 days. If seeds have any moisture, they’ll mold in their container.
Place dry seeds into a sealable glass jar, plastic container with sealable lid, seed packets, or brown paper bags.
Label the container with the seed type, variety, and date harvested. Add notes about the seed or planting instructions.
Store containers in a cool, dry, and dark place such as a garden shed, kitchen pantry, or refrigerator. In order to preserve the freshness and viability of the seed it needs to remain dormant and protected. No moisture, no sun, no soil, no extreme temperatures, and protected from insects and animals. A temperature between 32° and 41°F is ideal.
How long can you keep seeds before planting them?
It’s best to plant seeds within 1-2 years of saving them. If they’ve been saved and stored well, their germination rate should be around 80% for the first 1-2 years. After that, the germination rate decreases a little bit each year. Although, just like everything in nature, there are exceptions to the rules. Some species are known for having seeds that can lay dormant for 20-100+ years, only germinating when the right conditions are met.
Seed Scarification
It’s important to note that many seeds require a scarification process in order to germinate. They must endure some sort of damage in order to unfold and thrive. Scarification types include: heat (such as fire or scorching), a period of freeze and thaw (such as winter), a scrape or cut, and an acid chemical reaction (such as being eaten by an animal and pooped out). Many wildflower seeds must experience a “winter” in order to germinate and fireweed seeds need to burn in order to germinate in the wild. Seeds coming from a supplier will indicate on the packet any special instructions prior to planting.
A savvy seed-saver would note these details about the plants they harvested from so that whomever plants the seeds can simulate the right environmental conditions before planting. While this seems complicated, I’ve got an easy fix. When I plant seeds purchased from a supplier, I keep the seed packet so I can refer to these details/instructions when I save seeds and bundle them for a friend. If the wildflower seeds I’m saving need to experience a “winter” in order to germinate, I’ll note in my garden journal to place those saved seeds in the freezer a few months before springtime. Or, I’ll note to sow the seeds in late fall so they experience an actual winter. This would be detail to note on seed packets gifted to a friend.
A special note of gratitude to my friend Holly Morgan of Whole Woven Home, whom shared a handful of these seeds with me a few years ago. From her garden to mine, we’ve both enjoyed these plants. She also tipped me off to the gorgeous custom seed packet stamp.
Enjoy this post? Learn more gardening skills at this level in the Beginner Gardening Course