By Graham Towerton
This article will be about saving seeds to use in growing gardens in future years. So, the first question is:
What is Seed Saving?
Seed saving is the practice of collecting seeds from flowering plants and storing that seed for use in future years to plant and grow the same type of plant. There are countless numbers of plants that produce seeds and this is just one way of propagating plants. Some plants don’t produce seeds and propagate by other methods, but this article is all about the plants that can be grown from seed. There are many reasons for saving seeds:
- To keep for planting in your gardens in future years
- To preserve the genetic heritage of certain plant varieties to maintain the biodiversity of plant populations
- To sell or give away the seed to other growers
- To grow out for the possible development of new strains or varieties of the same plant
What types of plants produce seeds?
Many plants produce seeds that can then be used to grow new plants:
- Fruit trees, shrubs, and vines such as apples, mangoes, peaches, pears, plums, apricots, blueberries, grapes, raspberries, watermelons, and kiwi
- Forest trees such as maples, oaks, locusts, pines, spruce, redwoods, eucalyptus
- Flowers such as roses, echinacea, bachelors buttons, daisies, sunflowers, milkweed, and marigolds
- Herbs such as basil, chives, cilantro (coriander), mint, thyme, sage, oregano, rosemary
- Ground cover plants like clover, alfalfa, and vetch
- Grasses such as Bermuda, crabgrass, and fescue all produce seed while typically spreading by underground rhizomes
- Vegetables such as broccoli, radishes, lettuce, okra, beans, peas, carrots, peppers, cucumbers
Even mushrooms and other fungi produce spores as a type of seed to allow the next generation of growth.
Where do you find the seed?
Where you find the seed depends on the type of plant.
Seeds are typically found inside the fruit of fruits and vegetables (watermelons, oranges, apples, tomatoes, peppers, grapes, peaches, zucchini, and pumpkins) and are very easy to identify inside the ripe mature fruit of those plants. It is important for the fruit to fully mature and ripen as this improves the maturity and viability of the seed. For example, if you’ve eaten a watermelon with seeds in it, the white seeds you sometimes see are not mature, while the black seeds have developed their seed coat and are mature. Normally we eat zucchini and cucumbers when they are small and the seeds will not have fully developed and matured. With those types of fruit, you have to leave them on the plant until they fully grow and ripen (zucchini and cucumbers can get much larger and may turn a yellow or gold color when ripe).
Other seeds are found inside the mature heads of flowers or in seed pods that develop after flowers have been pollinated. Examples of seeds found in flower heads include marigolds, echinacea, lettuce, and roses where the seeds are at the base of the flower head and are ready to harvest when all of the petals have died and dried out. Examples of seeds that can be found in seed pods are beans, radishes, broccoli, peas, and okra which form and grow after the flower has been pollinated.
How to Harvest the Seed
For the seeds which are produced inside the fruit, I usually harvest two or three of the best quality fruit when they are fully mature. For example, with watermelons, cucumbers, and pumpkins, the fruit is ripe when the stalk has dried and easily detaches from the fruit. In the case of tomatoes and peppers, they should not be green but should have changed to their fully ripe color. In the case of seeds in pods, like okra, radishes, peas, and beans; I wait until the seed pod has dried out before I cut or pick the seed pod from the plant.
Choosing multiple fruits, pods, or flower heads from multiple plants is a good way to get a wide range of genetic diversity and seed viability. So, selecting seeds from 50 to 100 bean pods harvested from 20-30 plant is a good example. Selecting seeds from 3-4 pumpkins, watermelons or cucumbers harvested from different vines of the same type is also a good example.
For fruiting plants, I cut open the fruits, separate the seed from the flesh, and then put the seed in a kitchen mesh strainer so I can wash the seed and free it of any remaining fruit flesh. Then I place the seed on paper towels on a kitchen plate and leave it in a cool, dry place to let the seed dry out.
For flowering plants, I break open the flower heads and separate the seed from the other flower parts and then leave the seeds on a plate to dry.
For seeds in pods, I break open the mature pods, remove the seed and place it on a plate to dry.
I use countless different methods to store seeds depending on the variety. For plants with very large seeds like sunflowers, watermelons, beans, and pumpkins I store the seed in large containers. I’m a person who likes to recycle containers, so examples are containers for powdered sports drinks, yogurt, sour cream, and packaged meats. All of these containers have been cleaned and dried before use for seed storage and I clearly label the lids and outside of the container with the seeds and harvest date.
For smaller seeds (lettuce, marigolds) which I may have in large quantities, I might use the recycled plastic 8-16 ounce spice jars. For very small seeds like basil, I reuse vitamin or supplement bottles (labels removed).
For specific seeds which are small and that I only have in small quantities (like seeds from 3-4 jalapeno peppers) I will place the seeds into seed envelopes, or sometimes small plastic container organizers that might be used for organizing craft materials.
All of these containers and envelopes are then stored in clear plastic boxes so that I have easy access to them when I need them.
I also ensure that I label all containers with the plant name (e.g. peppers), the variety name (e.g. chocolate habanero), and the year of harvest. This becomes important when planning the gardens in future years as seeds have a certain shelf life before they start to decline in germination rates.
My boxes of seeds are kept in cool (55oF/13oC) conditions in my basement which is also generally low in humidity. Warm humid conditions should not be used for seed storage and excessively cold (freezing) conditions may destroy certain seeds.
Other Important Notes
Some other important aspects of seed saving should be observed by the most avid seed savers, especially those who might be trying to preserve specific varieties or genetics.
Certain plants are self-pollinating, which means the flower has male and female parts within it and the flower does not require pollen from other plants of the same variety. Examples of these are tomatoes and peppers. When you harvest the seed of these plants, the seed will generally grow “true to type” in that the next plant will produce the same type of fruit as the parent from which the seed was harvested.
Other plants require pollinator insects to visit the male and female flowers of a plant for the fruit to be viable and grow. An example is the squash varieties like pumpkins and zucchini which have male and female flowers on the same plant and pollinator insects (e.g. bees, wasps) transfer pollen from male to female. If you have only planted one variety of these plants, the resultant seed will also grow true to type. However, if pollen from another variety is transferred to your plant, the seed may result in a new variety sharing genetics from both parent plants or may favor one or the other parent plants. So, if I am trying to preserve the seed as true to type I will only grow one variety of pumpkin in a given year. Certain distances are recommended (not in this article) for maintaining separation between varieties that will cross-pollinate, such as squash and corn.
For plants that cross-pollinate, it is possible to grow multiple varieties and avoid cross-pollination. This year I grew two types of lettuce and each of these had different flowering times, separated by several weeks, because I planted the seeds at different times. Only one variety was flowering at any time and this reduces the chance of cross-pollination.
In the case of fruit trees like apples, there is often the need to place different varieties within the same orchard to create deliberate cross-pollination to increase fruit yields. This is because individual trees will not necessarily be self-fertile or may not be fertile with multiple trees of the same variety. In such situations, the seed of an apple may not grow to be true to the type of the parent tree and may have shared genetics with other apple varieties and crab apples which will pollinate fruiting apples. You will get an apple tree from an apple seed, but there will not be any certainty as to the variety. Such can be the case with certain varieties of citrus. For these trees, other propagation methods (grafting of cuttings) are generally practiced.
Some seeds are not seeds but are cloned embryos of the parent plant. The best example of this is the seed of mango (poly-embryonic type), which is a very small clone of the parent.
As mentioned previously, seeds have a shelf life and so I keep good records of seed harvest dates so I can know when to re-plant the seeds in future years and get another harvest of seeds to restart the cycle. Some seeds have only 1-2 year shelf lives (onions are a good example), while others may be many years. This year I successfully germinated seed from a watermelon that I grew in 1999. I did have very low germination rates (about 3 seeds in 100 germinated), but now I know that that variety can have a very long seed shelf life.
Some seeds do need cold conditions to be viable for germination. These are generally seeds of plants that grow in cold climates and need exposure to winter conditions and the warming afterward to germinate. The process of “stratification” is used to artificially expose these seeds to cold conditions for those who save seeds of these varieties.
A special note on seed types and naming:
- Open-pollinated seed means the plant was grown in an open environment and naturally pollinated by pollinator insects. This means it’s closely mimicking natural processes but may also mean that some cross-pollination may have occurred if variety separation practices weren’t observed.
- GMO means genetically modified organisms. Non-GMO means it’s not been genetically modified. Much of commercial agriculture seed has become genetically modified to produce plant traits that suit commercial agriculture purposes (e.g. diseases resistance, pesticide tolerance). These seeds may not grow true to type in future generations and many of these are patented plant varieties which mean you have to have a license to grow plants from those seeds and which means seed saving would violate the patent. I do not use GMO seeds.
- Certified Organic. This means that the crop used to produce the seed was grown using certified organic farming practices according to the organic certification standards of the country or region. This generally means the seed is free of synthetic chemicals and must be non-GMO.
- Heirloom or Heritage varieties. This implies the seed is a variety that will grow true to type and which has been grown for many years or perhaps even centuries. A “Roma” tomato variety is well known for its shape, it is commonly present in grocery stores and well known for its use in Italian meals and pastes/sauces. However within the Roma type, there are many varieties, some of which are heirlooms, others which are not. The grocery store varieties (e.g. Heinz) are grown large, round, firm, and red for surviving the rigors of commercial harvest, processing, and transportation; while an heirloom variety (e.g. San Marzano) might have very different qualities. Choosing heirloom varieties is a matter of preference based on the qualities of the fruit or plant; or as a choice to preserve these varieties for future generations to also use.
The Joys of Seed Saving
Whatever your level of knowledge and experience, it’s very easy to become a seed saver. I’ve saved seeds from grocery produce (e.g. watermelons) so that I could grow fruit that has been imported from other countries. I’ve grown seed that has been shared with me by other growers and likewise, I share seed with others so that the genetics can be preserved by others than myself. I’ve also packaged and sold seed as a business in Australia which turned out to be quite profitable (please follow the seed growing and marketing regulations in your location if you do this). I’ve preserved certain varieties now through several growing cycles and can consider them to be acclimatized to my local climate. I now save cherry tomato seeds in my garden soil and they grow back every year whether I want them to or not! Now and then I am surprised to see a different variety that may have resulted from cross-pollination or maybe a seed that was contaminated. Either way, I collect the seed and preserve it for future planting.
But for me, it’s the knowledge that at any given time I have 300+ varieties of plants to choose from in growing my next year’s garden and that provided I can plant the seed, I can then harvest a bountiful crop to go with my perennial fruit and berry harvests.