Open pollinated varieties, aka OPs, are like dog breeds; they will retain their distinct characteristics as long as they are mated with an individual of the same breed. This means, with a little care and planning, the seeds you produce will be true-to-type, keeping their distinct traits generation after generation as long as they do not cross-pollinate with other varieties of the same species.
Annual, Biennial, Perennial
Not all plants flower, set seed, and die in a single growing season. Those that do, like lettuce, tomatoes, and peppers, are called annuals. Biennials, such as carrots and onions, don’t flower until their second growing season, after they have gone through a cold period. Some long lived plants, like apple trees and asparagus, are perennial, surviving and flowering for many years.
Learn About Species
A species is a group of individuals that are able to reproduce together. In the garden, most crops are different species from one another, but not always. There are several species of squash and two distinct species of kale – meaning some varieties of these crops are not able to cross pollinate with each other. On the other hand, Cucumis melo, commonly categorized as a melon, also contains some varieties that are sold as cucumbers like ‘Armenian’ because fruits of the variety are unsweet and sometimes pickled.
2. Plan For Seed Saving
Start With Easy Crops
Some crops like peas, beans, lettuce, and tomatoes are great for beginning seed savers. These annual, self pollinating crops require little to no isolation, and only a few plants are needed to reliably produce seeds.
Grow Enough Plants
Some crops have a hard time producing seeds when too few plants are around. Others can reproduce with just a single plant. If the population size of a seed crop is too small, some genetic diversity may be lost and over many generations; in time this can result in a noticeable decrease in plant stature, overall vigor, germination, and yield.
Put A Little Space Between Varieties
In order to produce seeds that are true-to-type, a little garden intervention is needed to prevent unwanted cross pollination between different varieties of the same species. For some crops like lettuce and peas, all that is needed is a little extra space between varieties. For others, more advanced methods can be used, including larger isolation distances, pollination barriers, or hand pollination.
3. Collect Your Bounty
Know When Your Seeds Are Mature
For crops that produce wet fruits, the seeds are not always mature when the fruits are ready to eat. Eggplant, cucumber, and summer squash fruit are eaten when the fruits are immature and still edible, but before the seeds are actually mature. This means that seed savers need to leave a few fruits to fully mature in the garden when they want to save seeds. Dry fruited crops, like grains, lettuce, and beans, can be removed from the plant once seeds are dry and hard.
Know How To Harvest Seeds
Garden crops can be classified as either dry fruited or wet fruited. Collecting seeds from dry fruited crops, can be as simple as going out to the garden, handpicking a few mature seedpods, and bringing them into the house for further drying and cleaning. Fruits from wet fruited crops must be picked when their seeds are mature. The harvested fruits are either crushed or cut open, and the seeds are extracted from the flesh and pulp before the seeds are dried.
Seeds are happiest when they are stored in a cool, dark, and dry place. A dark closet in a cooler part of the house or a dry, cool basement are both good spaces to store seeds for a year or two. Once properly dried, seeds can also be sealed in airtight containers and stored in the refrigerator or freezer for several years. The seeds of some crops are naturally longer lived. Tomato seeds and beans can be left for many years in adequate storage conditions, while onion and carrot seeds are notoriously short lived. Don’t forget to label your seeds with the crop type, variety name, and any useful notes about your seed source, when you harvested the seeds, and how many plants you harvested from.