An Introduction to Seed Saving

By Marianne Lepa, Master Gardener In Training, SCMG

Seed saving is a fun and easy way to increase your garden plants for free. Buying plants from a nursery can be expensive and, even though seeds cost less, those seed orders can really add up. Especially if you have to buy a package of 100 seeds when you only want 6 plants.

 

Vegetable gardening is particularly suited to seed saving. When you save the seeds from your best performing plants, they pass on that ability to grow well and, over the years, they will become strong performers in your particular garden conditions.

 

The COVID pandemic caused a disruption in our food supply, but also to the supply of plants and seeds from nurseries. In 2020, we got a glimpse of how fragile our supply chain really is. When you save your own seed, your know your supply is secure and you have a bit of insurance against the ups and downs of the marketplace.

Some Biology

When animals and plants reproduce, each parent contributes half of the DNA that combines to create a new life. Fully understanding how DNA works in reproduction is a first year university science course. For our purposes it’s enough to picture two strings of beads twined together into a helix shape. Each bead carries the genetic code for various characteristics, such as flower colour, plant height, leaf shape and so on.

 

In reproduction, that double string splits in two. The single string from one parent, connects and twists together with the single string from the other parent. Now each bead on the string will have a new combination of characteristics. In the horticulture world, the two strings of plant DNA may be identical and the offspring will look exactly like parent. In others, there could be enough variation between beads that the offspring will look quite different. As seed savers, we need to be thinking about the parents that will grow our seed.

Know your parent stock

The first thing a seed saver needs to know is whether the plants they want to save seed from are annual, biennial or perennial.

  • Annuals mature and set seed in one growing season,
  • Biennials grow foliage in the first year and store energy for the flowering in the next season. They die after the second year. So if you plan to save seed from biennials, you need to plan two years out. Be aware that the second year plant can grow to 3 or 4 times the size of the first year plant or even larger.
  • Perennials, like biennials, grow foliage in the first year, but return and flower year after year. You can save seed from perennials, but the usual practice is to take stem cuttings or divide the roots instead.
  • Some plants, like potatoes or irises, grow tubers or rhizomes as well as seeds. Tubers that are harvested and saved for planting next year will grow clones of the parent, while the seeds will have different genetic information and may vary slightly from the parent.

 

An even more important thing to know is is if the plant you want to save seed from is an open pollinated plant or a hybrid plant.

 

Open pollinated varieties are often described as heirloom varieties. These are plants that have been sown from seeds that were saved and handed down for generations. The seeds came from fruits that were selected for good flavour or ability to survive short seasons and over time developed into the tasty vegetable that you harvest from your garden. The genes of these plants are consistent and come true from seed every year.

 

Hybrids, on the other hand, have been specially bred to have certain qualities. Flowers from one species were crossed with the flowers from another species in the hopes of combining certain traits. This means that the genetic material from each parent is different and will combine randomly over succeeding generations. While the vegetable you grow from a hybrid will be a tasty delight, the next generation may be anything but. The seeds saved from hybrid plants may grow plants that have no resemblance to the one you saved the seed from. So, if you plan to save seed, you will need to be sure that you are saving from an open pollinated variety.

 

And now a bit of botany

Pollination happens when pollen is transferred from flower anthers to flower stigma and triggers the development of seeds in the plant ovule. Some plants are able to self pollinate because their flowers contain both the anthers and stigma and are constructed such that the pollen will fall onto the stigma at the right time. Other plants will have male flowers with the anthers and female flowers with stigma. These plants need to cross pollinate to get viable fruits and seeds. The flowers are designed to attract insect pollinators to them so that they carry pollen from male flowers to female flowers.

Cross pollinating squash flowers: Male on left, female with ovule on right.

Evolution has created some amazing strategies for plants to attract pollinators. Usually, the food seeking insect senses or smells something tasty way down in that flower blossom and, in the process of reaching for the food, the insect gets covered in pollen from the anthers. Then the insect moves to the next flower where it will leave a dusting of pollen on the stigma and pollination takes place.

 

Self-pollinating plants benefit from the security of being able to pollinate no matter what. Self pollinating plants are more reliable seed producers, especially as pollinating insects are under threat. But they will not have the genetic diversity of cross pollinated plants. Cross pollinated plants have a wider genetic diversity that can help them adapt to changing environmental conditions, but they are fully reliant on having pollinating insects (or a helpful gardener) to transfer pollen.

 

Examples of self pollinators: beans, tomatoes, lettuce, peppers, eggplants and, surprisingly, sunflowers and poppies

 

Examples of cross pollinators: corn, carrots beets, spinach, radishes, winter and summer squashes and cucumbers.

 

If you are going to save seed from cross pollinating plants, it’s important to know who your female flowers have been consorting with. If your zucchini stigma is pollinated by pumpkin pollen, you will have a zucchini to harvest for eating and you won’t know the difference. But, if you were to let that zucchini grow out and save the seeds for replanting next year, there’s no way of knowing what you will get from those seeds. Some plants will surprise you by crossing with unexpected family members. For example, carrots will cross with Queen Anne’s Lace and spinach will cross with beets and Swiss chard.

 

How to save seeds

Now the plant has pollinated and the plant is growing seed for its next generation. The seed capsules grow surrounded with the necessary survival gear so the seeds have the best chance of success for  germination and growth. Every seed has a Coat, Embryo and Endosperm. The seed coat is a protective layer that keeps the seed safe and will split open when conditions are right. The embryo is the seedling leaves curled up and waiting for the signal to grow. These tiny leaves are designed to push through soil to where they can absorb light and create the energy for the roots to grow and prepare for the true leaves to come out. Beneath the coat and surrounding the embryo is the endosperm. This is the food supply to feed the embryo once the coat breaks open and until the seedling leaves can reach light and create food. The endosperm is the tasty part in our beans and peas.

 

As seed savers, we need to be aware of when our seeds are ripe and ready to be harvested. Pick them too soon and they won’t have the energy to germinate next season. Pick them too late, and you risk losing them to damp or being carried off.

 

It may be hard to bear, but choose the best fruits for saving your seed. The pea pods with the most peas inside; the first tomato that grows large and juicy; or the zinnia that had the brightest colour and grew on a straight stem. Leave the seed capsule on the plant as long as possible to be sure it’s fully mature. There is specific timing for particular plants, but, as a rule, you can harvest the seed after the stem has begun to yellow and the seed capsules appear dry.

 

You can search for instructions on how to save seed for particular plants by typing: seed saving {name of plant} into your favorite search engine.

 

Storage

 

It’s very important that your seeds are fully dried before storing. Letting your seeds rest inside paper bags (labelled, of course!) in a dry place for a few weeks ensures that they will be good and dry for storage. Properly dried seeds can be stored in plastic “zip lock” bags. However storing them in a paper envelope that allows them to breathe can reduce the changes of mold or rot. The paper will assist in keeping the seeds dry but not too dry. You can get small envelopes perfect for seed saving from an office supply store. Or, check out YouTube videos on the web for instruction on making your own from scrap paper.

 

Be sure to label your seeds with the type and variety. The year they were collected is also useful information if you plan to hold seeds over for more than one year.

 

Store seeds in a cool, dry place. They can be kept at a cool room temperature or in an air tight container in the fridge. Storing seeds in the freezer is controversial. While seed banks do freeze seeds for long term storage, it is done very carefully and in designated freezers to maintain a consistent temperature. Your home freezer will probably not be able to replicate those conditions. If the seeds are not dried to less than 10% moisture content, freezing can damage or kill them.

 

Some seeds can be stored for many years, some will not last more than a year. Parsnips, for example, do not last long in storage and should be planted the following spring. Old parsnip seed will have spotty germination at best. But, meanwhile, lettuce seed can store for up to 5 years and still germinate well.

 

 

Saving seeds is a fun way to expand your gardening skills. Start with seeds that are simple to save, such as peas or marigolds. As you gain confidence, you will find more seed types that you want to save. Be sure to label everything and be sure to have fun.