Seed saving is not quite as simple as just letting your tomato or zucchini dry up and saving the seed that’s left behind. To save your own seeds successfully - that is, to get seeds that will grow back “true” to the parent plant with all the same characteristics - you need to know a few things about seed types, genetics and pollination. I am going to define a few terms first before getting to the details, but stay with me - saving seeds is not hard, and is a fun and useful skill to have.
Some Terms to Know
“True” (or “True Breeding”).
This means that self-pollinated seed from a particular plant will grow up into a plant with all the same characteristics as the parent plants. An example is easier to see in dogs: it would be like breeding a greyhound with a greyhound - the offspring is going to be a greyhound.
This is a cross between two different varieties, each of which is true to itself. But the offspring are not true to either parent, because they shares genes from both.
In dog breeding, this would be like crossing a greyhound with a bloodhound, and getting puppies with traits from both: mid-weight, not too lean or too droopy, but sort of in-between the two.
But then if you took two of these offspring and bred them together, the puppies would be a wild mix of many different traits: lean with droopy ears, stout with little ears and pointy noses - all very unpredictable. The offspring would not be “true” at all to the parents.
This is a variety that has been “true” for many many generations, and has been intentionally bred and handed down through many human generations. (“Open-pollinated” is sometimes used to mean the same thing, but open-pollinated technically means that the flower has been pollinated out in the open, in nature, by bees or wind, and still remains true to type.)
Using our dog example, any of the registered AKC breeds could be considered “heirloom varieties" of dogs. There are heirloom breeds of chickens, pigs, and other farm animals, and in plants, examples of heirlooms would be Brandywine tomatoes or Cayenne peppers.
Species versus Variety
A species is an organism that only reproduces with itself. For example, you cannot cross a dog with a horse, or a tomato with a lettuce, because they are different species. Varieties, on the other hand, are different-looking strains of the same species, such as greyhounds and bloodhounds, or Brandywine tomatoes and Roma tomatoes. Varieties will cross with each other.
Why Modern Seeds Will Not Come Back True
Most of the seeds you buy in packets are hybrid varieties, intentionally bred by combining different “true” parent stocks. These hybrids have been deliberately crossed to enhance desirable characteristics, such as disease resistance, shortened time to maturity, good shipping qualities, or (if you’re a seed salesman) even second generation sterility.
If you try to save seeds from hybrids you will not be able to predict what characteristics the offspring are going to have. And of course - since the subsequent-generation seeds are unpredictable (or in some cases, sterile) - you have to go back to the seed company year after year to buy your seeds.
Another, more disturbing trend, is a practice known as “gene splicing”, where scientists in a specialized laboratory forcibly cross genes between species, something that does not occur in nature. (Mules excepted). Gene splicing produces what are known as “GMOs”, or Genetically Modified Organisms.
There are all kinds of very serious negative effects of this practice, but that is another story. Suffice it to say that even if you wanted to and were able, you are not allowed to reproduce GMOs. Yes, Virginia, you can patent a tomato, and a pig as well... and be sued (Sue...eee! Suue... eeee!) for growing them without a license. Even if they grow on your land from blown-in seed, or your pig gets out and breeds with a GMO pig, you can be sued.
How to Save Seeds That Will Come Back True
So if your seed saving efforts are going to bear fruit (so to speak), that is, to come back true to the parents, you need to pay attention to two things:
Heirloom seeds are making a bit of a comeback due to the dedicated efforts of a few people of great foresight and dedication. Heirloom seeds are getting easier to find at nurseries and garden centers, and even Home Depot now sells a selection of heirloom tomato seedlings in their garden department in the spring. But if you cannot find heirloom seeds locally, there are a variety of mail-order seed companies that supply them.
The trickiest part of seed saving is making sure that your flowers do not cross-pollinate, which means that you must find a way to prevent bees and other insects, and even the wind, from carrying pollen from other flowers to the seed saving flower(s) you have chosen.
You can isolate flowers in one of two ways. This first is by distance, or by growing your seed saving plants so far away from other varieties that there is no chance of cross-pollination.
This is impractical for most people, because that distance is great (usually outside the 3 mile radius that a honeybee will travel away from its home hive) and because you don’t know what other people around you are growing (unless you live at least 3 miles away from your nearest neighbor, in which case you'd be okay!).
The other way to isolate flowers is mechanically, by sealing the flower off from natural cross-pollination methods like wind and bees. The best way I have found is to make a little bag out of spun polyester row cover (“Reemay”) and to tie it over the flower, tightly enough around the stem that bees cannot crawl in underneath.
Now you have to watch very carefully for when the flower opens and is ready to pollinate. When the flower opens, you can either shake it, move the pollen from the orange-tipped anthers to the sticky stamen by hand, or even use an electric toothbrush to jiggle the stem of the flower, so that the pollen releases and pollinates the flower. After pollination, seal the bag up again for a day or two, to prevent further pollination by bees.
Different species of plant have different specific requirements for hand-pollinating, and to describe them all is beyond the scope of this article. But there is an excellent guide to the specifics available online at the International Seed Saving Institute.
While seed saving may seem complicated, it is really a wonderful way to become more connected to your garden and your food supply. Older generations used to offer the family's heirloom seeds as a gift to newlyweds, with the understanding that they were offering food and life. What a wonderful tradition! May your own seed saving skills become part of your family's traditions.