So, to the library!
While Suzanne Ashworth’s book “Seed to Seed” is the definitive guide to seed saving, as a novice I found it a little impenetrable. It’s the place to go for every nitty-gritty detail, but I needed a stronger general understanding before I could make best use of it. “Saving Seeds: The Gardener’s Guide to Growing and Saving Vegetable and Flower Seeds” by Marc Rogers was less intimidating to a beginning seed-saver like myself.
“Saving Seeds” is written for the home gardener learning to save seeds, with clear directions on how to prevent cross-fertilization in all the usual (and some unusual) garden vegetables, written in an approachable, conversational way. Most important, the author states clearly which seeds are easy to save (beans, peas, and tomato) and which should be left to the intrepid expert (cauliflower, beet).
The main points:
- Maintain genetic diversity by harvesting seed from multiple plants. If you harvest seed from a single plant each year, your stock will eventually get inbred and be more susceptible to disease (exception: saving seed from just a single squash or the self-pollinating beans and peas will not weaken the strain).
- Choose only your best plants and best fruits/vegetables from which to harvest seed.
- Decide what you want to emphasize – earliest tomatoes? turnips that keep well all winter? disease resistance? lettuce that bolts latest in the summer? dwarf variety for container planting?
- If you just save what’s left at the end of the summer (like I was) you’ll end up selecting for the latest-producing peas and beans, rather than the earliest.
- Isolation to prevent cross-pollinating – how to do it and when is it necessary?
- Beans, peas, lettuce, and tomatoes are self-pollinating and rarely cross-pollinate even between varieties (e.g. my Black Cherry tomato is unlikely to cross with a Brandywine tomato), but it can be a good idea to separate varieties with a different kind of plant.
- Since isolation by distance for corn, cucumber, squash, melons, eggplant, and peppers is impractical in the confines of a home garden, you can bag the flowers to prevent them from being cross-pollinated by different varieties. Bagged blossoms of corn, squash and melons must be hand pollinated, while the eggplant and peppers will self-pollinate.
- Members of the brassica (broccoli, cabbage, etc.), mustard (turnip, chinese cabbage, etc), and celery (parsley, carrot, etc) families are biennials and in my zone most must be dug and overwintered, then replanted in the spring to produce seed the second year. Almost all of these must also be physically isolated (flowers bagged) to prevent crossing.