From Build Your Arc, by Geri Welzel Guidetti
Saving Your Own Seeds
One of the main reasons for growing open-pollinated or non-hybrid fruit and vegetable plant varieties is to enable you to save your own seed from year to year. This eliminates the need to buy seed commercially, thus decreasing your dependence on others for your food and increasing your self-sufficiency. This is increasingly important because open-pollinated varieties are rapidly disappearing from commercial seed catalogs, ensuring for seed companies that you and I will come back to them, year in and year out, to buy their proprietary hybrid and protected plant varieties. This may seem defensible in good times when there are no significant crop failures, droughts, floods, fuel or fertilizer shortages, economic crises, etc., and when you have the money to buy all of the seed you need to grow your food. It might well become a problem if any of the above were to occur.
Saving seed from open-pollinated plants can be a fairly easy undertaking or it can be more challenging, depending on the types of plants you choose to grow and how close to your property similar plants are being grown by someone else. Some plants cross easily with others and will yield seed which carries traits of both. The plants you get from those crossed seed will not be identical to either parent. In some plants, like tomatoes, such crosses are infrequent and, when they occur, still tend to produce usable tomatoes. In others, like squashes belonging to the same species groups, crosses occur readily and result in seeds that rarely produce squashes of quality equal to that of either parent.
There are ways to minimize or prevent the crossing of varieties by wind, bees or other insects. One is to grow only one type of squash of each species, one kind of onion, eggplant and so on. But if your neighbors within a mile of your property are growing other varieties of these plants, bees will certainly cross-pollinate a few or more of them anyway. Another technique is to cage plants you want to collect seed from. Cages must be screened with material that wont allow pollinating insects to enter. Another, more labor intensive but more reliable technique is to hand pollinate plants from which you plan to save seed. These techniques are fairly easy to learn and can be very interesting and rewarding.