Your Garden’s Legacy: Seed Harvesting and Saving
Though I do not believe that a plant will spring up where no seed has
been, I have great faith in a seed. Convince me that you have a seed
there, and I am prepared to expect wonders.
- Henry David Thoreau
Well, you’ve successfully applied what you’ve learned about good sound soil management, studiously planned and planted, bravely confronted each pest and disease that came along with well-researched organic solutions and proudly harvested the fruits of your labor! Congrats! Now…for your last frontier…the last uncharted part of your gardening journey… seed harvesting and saving !
First, a bit of basic botany…
Life Cycles of Plants
Plants are classified by the number of growing seasons required to complete a life cycle. Annuals pass through their entire life cycle from seed germination to seed production in one growing season and then die.
Biennials are plants which start from seeds and produce vegetative structures and food storage organs the first season. This group, which includes most of the root crops, grows vegetatively the first season. During the first winter a hardy evergreen rosette of basal leaves persists. During the second season flowers, fruit, and seeds develop to complete the life cycle. The plant then dies. Carrots, beets, cabbage, celery, and onions are biennial plants. Hollyhock, Canterbury Bells, and Sweet William are biennials which are commonly grown for their attractive flowers.
Plants which typically develop as biennials may, in some cases, complete the cycle of growth from seed germination to seed production in only one growing season. This situation occurs when drought, variations in temperature or other climatic conditions are experienced. These cause the plant to physiologically pass through the equivalent of two growing seasons, in a single growing season. This phenomenon is referred to as bolting.
Perennial plants live for years, and after reaching maturity, typically produce flowers and seeds each year. Perennials are classified as herbaceous if the top dies back to the ground each winter and new stems grow from the roots each spring. They are classified as woody if the top persists, as in shrubs or trees.
(source: Univ. of Az MG Manual)
Parts of a Plant
How Your Plant Produces Seeds
Leaves make all the food for the plant. They do this by changing light, water and gases into food. This process is called photosynthesis.
Stems and branches
Stems and branches hold up the leaves and space the leaves out. This helps the plant to get the light it needs.
Roots help fix the plant to the soil or to other plants. Roots take in water and nutrients.
Plants create seeds when they become mature enough to produce fruits or flowers, which are their seed-making and seed-distribution mechanisms. Seed plant propagation requires interaction between the male and female parts of the plant–the stamens and pistils, respectively. Pollination, or the fertilization needed for seed production, takes place when pollen from the stamens reaches the seed ovules in the pistils. Then new seeds are born, grow to ripeness and are ready to create a new plant.
Stamens and Pistils
As a plant matures it begins producing foliage and roots, which draw in nutrients and light. It also grows its sex organs, the male stamens and the female pistils, that produce seeds. Both sex organs are contained in the flowering parts of plants. Stamens are usually visible as slender stalks with caps containing pollen, a sticky, dust-like substance that is the male fertilizer. Pistils are usually found in protected growths at the base of a plant’s flowers. They contain the seed ovules, which become seeds once they are fertilized.
Male – Stamen including the anther and filament.
Female – Pistil including the stigma, style and ovary.
There are three pollination methods of concern to the home gardener: air-borne, insect and self. If the seed produced is to have the same genetic composition of its parents, it must be pollinated with pollen from the same variety. Open-pollinated varieties will grow true to type when randomly mated within their own variety. If two varieties of spinach bloom near each other, the resultant seed is likely to be a cross between the two.
In the case of air-borne pollinated crops in a commercial farm setting, there must be no other varieties within a mile shedding pollen at the same time. If there is, some of the harvested seed will result from a cross between these two varieties. The closer the varieties are located, the higher the percentage of crossing.
In commercial farming, if a crop is insect pollinated, there should be a 1/4 mile separating varieties. Otherwise, some of the seed saved may result from the crossing of the varieties located within this 1/4-mile radius.
Self-pollinated crops offer the best opportunity for a home Gardener to save seed because the pollen is transferred directly to the stigma within the flower. Even though this occurs automatically, there is some pollen that escapes and can be transferred to an adjacent variety. To avoid this, separate varieties by a few rows of another crop.
A seed consists of three main parts: the seed coat, the endosperm, and the embryo. Of these parts, the embryo is clearly the most important. Its cells will differentiate and develop into all the different tissues that will ultimately make up the mature plant. The other parts of the seed play merely supporting roles. These roles, nonetheless, are critical to the embryo’s success.
The seed coat protects the internal parts of the seed during a period called dormancy, prior to germination. Dormancy is a protected state during which a seed “waits” for favorable growing conditions (soil temperature, moisture). The seed coats of some seeds allow them to wait a very long time. The oldest known viable seeds were from an East Indian lotus. They were 466 years old when they germinated.
Germination usually begins when the embryo is exposed to water. The water swells the embryo inside, bursting the seed coat and setting growth into motion. During the earliest phase of growth, when the embryo has no leaves and therefore no means of photosynthesis, the endosperm serves as a food source. It serves the same function as the yolk in a bird egg, providing high-energy food to the developing embryo.
The embryo of a seed has three main parts: the primary root, the cotyledon(s) (there are two in many kinds of plants), and the embryonic leaves. The primary root, or radicle, is the first structure to emerge from the seed during germination. It penetrates the soil very rapidly, forming a slender, usually unbranched taproot, which, in some plants, may penetrate several feet into the soil during the first few weeks of growth.
During this period, the cotyledon serves a function similar to that of the endosperm, supplying food to other parts of the developing embryo. Not surprisingly, the embryonic leaves, also known as seed leaves, develop into the plant’s first leaves above ground. These leaves open within a few days after the plant emerges from the soil and begin photosynthesizing almost immediately to provide the growing seedling with its new — and renewable — food source. (source: Teachersdomain.org, Colorado State Univ. Ext.)
SEED SAVING TECHNIQUES
Not all Garden plants produce their seed at the end of the growing season. The most noteworthy exception are the biennials. This group, which includes most of the root Crops, grows vegetatively the first season. To obtain seed, the roots are dug in the fall and stored between 32 and 45 degrees F through the winter. As soon as the weather permits, replant the roots to produce seed stalks and seed.
Hybrids result from a deliberate cross between two inbred lines. They are becoming increasingly popular because they usually are more disease resistant and vigorous than open-pollinated varieties. Seed saved from hybrids produces many different plant types and are not true to the parent plant which may be a disappointment for gardener who has unknowingly saved and planted hybrid seed. Seeds saved from hyprids may not produce the desired results. Nearly all corn varieties are hybrid. To be sure, check the package to see if it says “F1 hybrid.” F2 plants are not hybrids and lend themselves to seed saving.
Heirloom seeds provide much more reliable results.
Seed is taken from fruit after it ripens and before it rots. Leave summer squash and cucumbers on the vine until after frost, just like winter squash and pumpkin. Separate the seed from its pulp and dry at room temperature.
Leave pod crops on the vine until the pod dries. Harvest before the seed is dispersed. Similarly, harvest seed heads after they dry but before dispersal.
Common methods of preparing your seeds:
1) Allowing the seeds to dry naturally on the plant. Corn and garlic would be a good representative of this method. Pull the corn husks when the corn as fully ripened and allow to continued drying on racks (if protected from birds and squirrels) or in paper grocery sacks indoors until they are thoroughly dried. Then you can twist them in your hands to get the kernels to fall off. Package, label with name of variety and date or year of harvest and store. For garlic, the same drying method applies. Garlic can also be braided and hung from nails, or stored in open weaved bags while they are drying. This is also referred to as “curing” when in reference to garlic. Lettuce and cole crops such as broccoli seeds can be collected directly from the plant. When you notice the seeds look dry and about ready to fall off, then you can directly pull the seeds off by hand into a waiting paper bag.
2) Removing the seeds and allowing to air dry. This would be the most common methods of vegetable seed storage. For example, cucumbers and other squash type plants. Allow the fruits to fully ripen even to the point of the fruit starting to turn yellow so that the seeds inside fully develop. Then cut open the vegetable and scoop out the seeds. It is recommended to give the seeds a gentle washing in a mild bleach solution (one part bleach to ten parts water) and then lay out in a single layer on newspaper or paper towels until the seeds have thoroughly dried. Then store in containers of choice with appropriate labeling.
3) For bean and pea plants, again, allow the pods to ripen fully on the plant, then remove the pods, open and out pop the seeds! You will probably want to let the seeds dry out some more if they appear to need it.
This method is needed for tomatoes as the viscous gel substance or pulp, inhibits germination so must be removed. The easiest way to do this is to slice open your tomato, squeeze the contents into a glass jar, add water up to about ¾ of the jar, stir and set aside for a few days. You will notice a icky smelly moldy residue collecting on the top of the water as well as some seeds (these are dead seeds). The water will clear and the good seeds will sink to the bottom of the jar. After about 4-5 days this process will seem to have come to an end, so carefully scoop out the stuff from the top and throw away, pour off the water down the sink, and then lastly, pour out the seeds from the bottom of the jar onto newspaper or paper towel for the final drying. When the seeds have dried, they can be removed from the paper and stored. (source: www.virtualseeds.com)
Before you store your seeds, make sure that you have thoroughly dried them. Home-saved seeds will retain their vigor if thoroughly dried and saved in air proof containers in the freezer for extended storage (some have said-I’ve never tried this) or in a cool dry cellar for next season. While some vegetable seed can remain viable in storage for as long as 15 years or more, and grains may remain viable much longer under stable environmental conditions, every year in storage will decrease the amount of seed that will germinate. When you have processed the seeds and are ready to package for the winter, it pays to buy desicant paks for your storage containers to keep your seeds dry. Seeds should contain 3-5 percent moisture while in storage. General rule is if your can bend your seed then it still has too much moisture in it and will rupture and die if frozen. However, if you attempt to bend it and it breaks instead, then it’s probably at 8% or less and can be safely frozen. Another point is that when you remove the seeds from the freezer, allow them to come up to room temperature before handling for planting or sowing. Saving seeds in storage will safeguard your family’s food crop in the event of world-wide catastrophes, war, pandemic outbreaks and other unforeseen disasters. Once the seed is dried, gently hand rub to rid it of any chaff, then store in an envelope in a cool, dry, rodent-free place.
So that about covers it. The wonders you’ll discover by trying seed saving is really what is at the core of edible landscaping: enjoying the edible at all stages of its life and of course…the gift of the next generation of beautiful and productive edibles. Enjoy!
Here are links to more veggie-specific seed saving techniques from some of HGEL’s favs:
Oregon State University: Seed Saving Basics
Organic Seed Alliance: A Seed Saving Guide for Gardeners and Farmers
Seed Saving and Seed Saving Resources
Interesting articles on Seed saving & Seed banks: http://www.independent.com/news/2011/may/08/save-seeds/