A south Georgia gardener not noted for grocery shopping made a special trip to the supermarket last spring. He brought home a package of dried beans.

"I like these," he told his wife. "I'm going to plant them." And all this summer, as they picked those delicious beans, she had to admit he wasn't crazy after all.

His strategy worked for two reasons, said Darbie Granberry, a University of Georgia horticulturist. One, the beans he bought happened to be from an open-pollinated variety. And two, dried beans are harvested much the way you need to pick them if you want to save seeds from your own garden.

"We don't normally recommend planting dried beans from the grocery store," said Granberry, a vegetable scientist on the Tifton, Ga., campus of the UGA College of Agricultural and Environmental Sciences.

"You just don't know whether the beans might have come from a hybrid cultivar," he said. "And if they did, it can be a disaster."

Producing a hybrid cultivar requires specific cross-breeding, he said. The seeds from this planned crossing are genetically unique. They can't be reproduced except by repeating the cross, using the same inbred lines as parents.

If you plant the seeds of the hybrids, you can't predict the kind of plants you'll get.

"They will probably be nothing like the hybrid parent from which you saved the seeds," he said. "Don't waste time by saving seeds from hybrids."

Even open-pollinated varieties may not be worth the trouble of saving seeds.

"Seed costs for a garden are usually nominal," Granberry said. "Saving good-quality, disease-free seeds may require considerable time and effort. And the quality of the saved seeds is usually less than that of new, commercially prepared seeds."

In special cases involving heirloom or hard-to-find cultivars, you may need to save seeds to keep a supply.

"Seeds from open-pollinated cultivars will be true to type," he said, "if they haven't been cross-pollinated with other, different cultivars."

To be sure you get true-to-type seeds, he said, plant only one cultivar of a specific vegetable. Or vary the planting dates so different cultivars don't flower at the same time.

You can keep the seeds of self-pollinating cultivars (including beans, peas and tomatoes) genetically pure by planting them 150-200 feet apart.

"Insect-pollinated plants usually cross-pollinate unless they're about a quarter-mile apart," he said. "That's not feasible for most gardeners."

To save seeds from your garden, pick them only after they're fully ripe, Granberry said. For seeds in fleshy fruits, that usually means when the fruit itself is fully ripe. For summer squash, eggplants and cucumbers, this would be two to three weeks after they're ready to eat.

"Edible seeds such as corn, peas and beans usually need to ripen several weeks beyond the tender eating stage," he said.

Separate mature seeds from the fruit, cob, hull or other tissue. Then dry them. Rinse seeds from fleshy fruits with water and allow them to dry on paper towels. Bean and pea seeds are best left to dry in the pods. Store the dry seeds in a moisture-proof container at room temperature or cooler.

The seeds will store best in the freezer. But make sure they're properly dried and in a moisture-proof container. And when you take them out, allow them to warm up before you handle them. Frozen seeds are fragile.

"Collected, dried and stored properly, most garden seeds will germinate well for one to three years," Granberry said. "Onion seeds, though, may remain viable for only eight to 10 months."

As for dried beans from the grocery store, it's best to look for some commercial seeds. "If you can't find them, though, give it a try," he said. "It might work out OK."