In 2018, I went to an organic gardening summer conference in Massachusetts. It was perfect timing because I was at the beginning of my organic gardening journey. One session I signed up for was titled ‘Seed Stories’. While I thought I was going to a session on how to save seeds, this session was different. In fact, there was discussion about seed saving, however, it was about the history of saving heirloom seeds. More specifically, we learned where certain seeds originated and how they were passed down from generation to generation. An heirloom seed is a seed that has been in existence for more than 50 years. The main message of the session was how important it is to save and preserve seeds. With that said, let’s dive in and learn more about how to save seeds from your garden.

Estimated reading time: 21 minutes

Why Save Seeds?

There are several benefits of seed saving. Here are a few:

• Saving money – seed saving directly correlates to saving money. Each seed you save means that you do not have to purchase new seeds of the variety saved.
• Preserving heirloom varieties – Heirloom varieties are seeds that have been in existence for over 50 years. Someone took the time to continuously save these seeds year after year.
• Develop a deeper understanding of a plant’s lifecycle – Careful observation of the lifecycle of a plant is required when saving seeds. By this observation, you are learning more about the plant.
• Have a plant that does well in your environment – when saving seeds, we choose those plants that have done the best in our garden. Over the years, the plant will continue to adapt and hopefully be bountiful.
• Having seeds to share with family and friends – it’s so nice to share seeds with others who share your passion for gardening. Further, it’s more special when you saved the seeds that are being shared.
• Preserving biodiversity within our broader environment – by saving seeds you ensure that a particular variety of plants continues.

Understanding Seeds

There is basic information that’s important to understand as you begin your seed-saving journey.

• Basic anatomy of a seed
• Types of seeds
• Pollination

Basic anatomy of a seed

A seed is an embryo and has everything it needs to form a plant. This includes carbohydrates, fat, protein, and minerals to sustain the dormant seed. In other words, a seed is alive.

When we think about seed production in plants, the thing to remember is the process begins with the formation of a flower. Seed production ends with a mature seed.

Types of seeds

Next, it’s important to understand the type of plant from which you are saving seeds. There are three types of plants.

• Annual – annual plants will bear seed in the same season in which they are planted. Therefore, it’s easiest to save seeds from annuals. Annual crops include tomatoes, cucumbers, eggplant, lettuce, peas, beans, dill, cilantro, basil, marigolds, zinnia, and snapdragons.
• Biennial – biannual plants take two years to produce seeds. During the first year, they produce their crops and in the second year produce seeds. If you live in a gardening zone where temperatures get below freezing, then plants will either need to be brought in during the winter or covered (row cover or leaves) to keep them warm. Biennial crops include Beet, brussels sprouts, cabbage, carrot, cauliflower, celery, onion parsley, swiss chard, and turnips.
• Perennial – perennial plants are plants that return year after year. Examples of perennial vegetables include asparagus and rhubarb. Examples of perennial flowers include lupine, milkweed, coreopsis, and echinacea. Seed saving from perennial plants is beyond the scope of this presentation. However, in many cases, you can simply leave a few flower heads to dry on the plant and let the wind disperse the seeds.

Pollination

In terms of pollination, we will look at the following.

• Open-pollinated vs hybrid seed
• Types of pollination and the impact on seed saving

Open-pollinated vs hybrid seed

Open-pollinated refers to plants that have been pollinated naturally by wind, insects, birds, or human hands. Hybrid pollination refers to plants pollinated by human intervention. The pollen of two different species or varieties is cross-pollinated resulting in a new hybrid variety.

• Seed from open-pollinated plants will remain consistent from year to year and can be saved (assuming cross-pollination has not occurred). We will take a further look at cross-pollination below.
• Seed from hybrid plants is not stable and thus not recommended for saving. While you can save seeds from hybrid plants, the mature plant will revert to one of the initial plants that went into making the hybrid.

Types of Pollination and the Impact on seed saving

Plants are either self-pollinating or depend upon pollination by insects, birds, or human hands. Self-pollinating plants include tomatoes, eggplant, peppers, peas, and lettuce. The flowers of these plants are considered perfect flowers. They contain both the anthers (pollen producers) and the pistils (pollen receivers).

Plants that depend upon pollination by wind, insects, birds, or human hands include cucumber, squash, corn, pumpkin, and watermelon. These plants have both male and female flowers. Pollen must be transferred from the male flower to the female flower by wind, insects, birds, or human hands.

Cross-pollination

Cross-pollination occurs when the wind or an insect transfers pollen from one variety of plants to another variety of plants. While the current year’s crop will not be impacted, the seeds from cross-pollinated plants will not have the characteristics of the original seed. If you want to save seeds from plants that are wind/insect pollinated, I recommend that you only plant one variety of that plant in a season. For example, only plant one variety of cucumber or squash.

To better understand which plants can cross-pollinate, it helps to understand the botanical information of the plant. Let’s focus on the botanical information of family, genus, and species.

For example, cucumber, squash, melon, and pumpkin have the following botanical classification:

Family: Cucurbitaceae

Genus: Cucurbita

#	Plant	Family	Genus	Variety	Species
1	Cucumber	Cucurbitaceae	Cucurbita	Pickling	sativus
2	Cucumber	Cucurbitaceae	Cucurbita	Lemon	sativus
3	Zucchini	Cucurbitaceae	Cucurbita	Dark Green	pepo
4	Zucchini	Cucurbitaceae	Cucurbita	Midnight Lighting	pepo

In the example above, the two varieties of cucumbers (1 and 2) will cross-pollinate if planted within the same garden during the same season. In addition, the two varieties of zucchini (3 and 4) will cross-pollinate. However, the cucumbers will not cross-pollinate with the zucchini because they are from different species. Therefore, for plants to cross-pollinate they must have the same family, genus, and species and must be wind/insect pollinated.

Let’s look at a second example of plants in the Brassicaceae family.

#	Plant	Family	Genus	Variety	Species
1	Kale	Brassicaceae	Brassica	Lacinato	oleracea
2	Broccoli	Brassicaceae	Brassica	De Cicco	oleracea
3	Brussels Sprouts	Brassicaceae	Brassica	Catskill	oleracea

In the case of the Brassica Genus, these plants share the same species and thus will cross-pollinate with each other.

How to save seeds?

Now that we have the background information, let’s look at the actual seed-saving process. Remember, seed saving takes time, planning, and patience.

Step One – Choose Plants

Annual crops are the easiest to save seed.

Step Two – Planning

Pick the healthiest plant as your seed parent. Observe the plants as they grow during the season and select the best. In addition, consider size, taste, yield, germination, and disease resistance.

Step Three – Harvesting Seeds

There are two types of seeds and the harvesting process is different based on the seed type.

• Wet seeds are seeds from plants such as tomatoes, cucumbers, squash, and eggplant. The seeds are contained within the fruit. Harvest seeds when the fruit is at its ripest. Here are a few examples:
  • Tomatoes require a fermentation process. Harvest the seeds when a tomato is at its ripest.
  • Cucumbers and melon seeds can either be fermented or scraped out, washed, and laid out to dry. Let the cucumber/squash stay on the plant until it is past its ripest point and off-color.
  • Squash, pumpkin, peppers, and eggplant seeds can be separated from the fruit flesh, washed, and laid out to dry. In the case of peppers and eggplant, leave the fruit on the plant until it is overripe and begins to wrinkle.

• Dry seeds are held by the plant in some type of pod or husk. Dry seed plants include peas, beans, lettuce, spinach, broccoli, kale, and corn. The pod needs to thoroughly dry on the plant before being harvested for seeds. This will generally happen at the end of a plant’s lifecycle. The pod will turn brown, and you may be able to hear the seeds rattle inside the pod if shaken. If the pod is not picked, then the seeds will be disbursed by the wind when the pod breaks open.
  • You may hear the terminology of a plant ‘going to seed’ or bolting. This happens when an annual plant is mature and ready to produce seed. The plant produces a flower stalk and seed formation follows.

Step Four – Drying Seeds

It is important for seeds to be completely dry before storing. Seed drying can take anywhere from 3 days to 2 weeks. To prevent seeds from sticking, lay seeds out on a coffee filter. To determine when a seed is thoroughly dry do a few tests.

• Test whether the seed can be snapped by bending the seed. Dry seeds can be snapped. This type of test is good for cucumbers, squash, tomatoes, eggplant, pumpkin, and peppers.
• For large round seeds, test if the seed shatters. Tap the seed with a hammer. A dry seed will break open. This test is appropriate for peas, beans, and nasturtium.
• For small seeds from lettuce, kale, and spinach compare to the seeds that were originally purchased.

Step Five – Storing Seeds

In general, seeds need to be stored in a dry and cool location to maintain nutrients and inhibit germination. Considerations for seed storage are temperature, moisture, and consistency. Seed storage will impact the viability of seeds in future years.

• A temperature between 32° and 41°F is perfect. Storing seeds in the refrigerator is a good option.
• Place the seeds in an envelope. To prevent dampness, add a packet of silica gel or dry rice to the envelope.
• Label the envelope with the following information:
  • Type of seed (e.g., Dill)
  • Variety (e.g., Banquet)
  • Date Saved
• To keep the seeds dry, place the envelope in an airtight container.
• Lastly, store in a location that is consistent regarding temperature and moisture. For example, the garage or a basement are not good places to store seeds because the temperature and moisture levels are inconsistent over time.

How to techniques by plant type

Tomatoes

• Tomatoes must go through a fermentation process.
• When tomatoes are fully ripened, scoop out the seeds and the gelatin that surrounds the seed.
• Put the seeds and gelatin in a glass container and add water.
• Over the course of 5 days, stir the seed mixture twice a day. The viable seeds will sink to the bottom of the container during this fermentation process.
• Pour off the liquid and any seeds that are floating on top of the water (these seeds are not viable). Rinse and dry the seeds that sank to the bottom of the container. Spread out the seeds on coffee filters or paper towels to dry.

Eggplant and Peppers

• Let the fruit overripen on the plant. The skin of the plant will be wrinkly. In the case of a pepper, wait for it to turn red or yellow. In the case of eggplant, the skin will be off-color.
• Cut open the fruit and remove the seeds.
• Rinse the seeds under water and separate them from any part of the plant.
• Dry the seeds by placing them on a coffee filter or paper towel for 2-3 days.
• Use the ‘snap’ test to see if the seed is dry.

Cucumbers

• Allow cucumbers to overripen on the plant. An overripe cucumber will turn a shade of yellow when it reaches this point.
• Cut open the cucumber and remove the seeds from the fruit.
• Rinse the seeds under water and separate them from any part of the plant.
• Dry the seeds by placing them on a coffee filter or paper towel for 2-3 days.
• Use the ‘snap’ test to see if the seed is dry.

Peas and Beans

• Leave the pods on the plant until they turn brown. This can take 4-6 weeks after you have harvested the edible crop. You should be able to hear the seeds rattle within the pod.
• Place the pods on a paper towel (do not open the pod) and allow them to dry for an additional two weeks.
• After the two weeks, you can either open the pods and store the seeds or leave the seeds in the pod until planting.
• Use the shatter test to determine if the seed is dry. Tap the seed with a hammer and check if the seed shatters. If the seed shatters, it is dry.

Brassicas (Broccoli, Kale, Collard Greens)

• Allow the plants to bolt (e.g., produce flower stalks). Brassicas will have yellow flowers.
• After flowering, pods will form on the branches.
• Leave the pods on the branches until they turn brown. This process can take 4-8 weeks.
• Place the mature pods in a paper bag and let them dry out.
• When dry, the pods will open, and drop the seed in the bag.

Lettuce, Arugula, Spinach

• Allow the plants to bolt (e.g., produce flower stalks).
• Let the flower stalk stay on the plant until the flowers are completely dried out. You may notice white fluff at the end of each seed head.
• Cut the seed stalk and place it upside down inside a paper bag.
• Shake and crumple the end of the bag each day for a few days.
• Dump out the seeds and separate the seeds from the fluff and chaff.
• Let dry on a coffee filter for a day or two and then store.

Dill and Cilantro

Dill and cilantro are members of the Apiaceae / Umbelliferae family (which includes parsley, fennel, cilantro, celery, and carrots). The common characteristic of this family is the umbel flower heads that develop. Seeds are harvested at the end of the plant’s lifecycle when the umbel flower heads turn from yellow to brown. Here is the process:

• Let the flower dry and turn brown while still on the stem.
• After the flower turns brown, cut the stem with garden shears or scissors. You will seed the seeds at the end of each stem of the umbel.
• Let the flower head dry for an additional week or two in a cool dry location. I place mine inside a paper bag (flower head upside down into the bag) to catch any seeds that fall during the drying process. Poke a few holes in the bag to allow air circulation. In addition, you can bunch multiple flower heads together in the same bag.
• After the head dries, gently massage the head while it is still in the bag and/or shake. The seeds will release from the seed head and fall into the bottom of the bag.
• Open the bag, take the seed head(s) out, and pour out the seeds onto a dry paper towel.
• Carefully separate the seeds from the rest of the chaff. I used a small knife to separate the seeds into a pile.
• Dill seeds are oval with a light border and a darker center with lines.
• Cilantro seeds are round. The cilantro seed is coriander.

Zinnias and Marigolds

• Choose the flowers that appear healthiest.
• Choose a variety of colors or your favorite color.
• Let the flower turn brown and brittle on the stem. The seed is attached to the shriveled flowers.
• After the flower turns brown, cut the stem with garden shears or scissors.
• Label the variety and color of the flower. You will be happy you did this when you go to plant the seeds.
• Let the flower head dry an additional week or two in a cool dry location. I place mine on a paper towel in an area where they will not be disturbed.
• Gently pull apart the flower head and let everything drop on a paper towel.
• Carefully separate the seeds from the rest of the chaff. I used a small knife to separate the seeds into a pile.
• Zinnia seeds are arrow-shaped and attached at the end of the flower petals.
• The Marigold seed is arrow-shaped with the top being darker than the bottom.

Life Expectancy of Seeds

Let’s look at a comparison of how long vegetable seeds can be saved based upon three different resources. While there is general agreement across the three resources, there are also a few exceptions. Lettuce stands out as a rather significant difference. I don’t have a research-based explanation for the difference in lettuce seed viability. However, what I did notice is that earlier research (1970s) of lettuce seed viability indicated that lettuce seed is only viable for one year. Today, newer varieties of lettuce can be stored for a longer period.

Vegetables

Flowers

Next, we look at a seed viability chart for some common flowers based on information from two different seed companies. Again, while there are a few differences, nothing is significant.

Additional Information

You may find the following blog posts interesting.

• Saving Zinnia Seeds
• Saving Dill Seeds
• The Complete Guide to Starting Seeds Indoors
• How to store and organize a Seed Collection

References

• Penn State Extension
• Oregon State Extension
• University of Minnesota Extension