Therefore, never save the seed from hybrids. Another major problem is some plants' flowers are open pollinated by insects, wind or people. These plants include squash, cucumbers, melon, parsley, cabbage, chard, broccoli, mustard greens, celery, spinach, cauliflower, kale, radish, beets, onion, and basil. These plants cross with others within their family. The only way to maintain the original variety is to isolate by large distances.
Isolation is often impossible or impractical in a home garden.
Some seeds may transmit certain diseases. A disease that infected a crop at the end of the growing season may do little damage to that crop. However, if the seed is saved and planted the following year, the disease may severely injure or even kill the young plants. Standard or heirloom varieties that are not cross-pollinated by nearby plants are good candidates. Many gardeners successfully keep beans, tomatoes, lettuce, and peppers.