If you've ever kept a compost pile, then most likely you've seen some volunteer squash or tomatoes growing out of it at some point and thought to yourself, “How did that grow there? I didn't plant it.” Well, the nature of seeds is to grow, and of course many of the fruits and vegetables we buy from the store have viable seeds which are waiting to grow. The compost pile usually presents ideal conditions. As does your garden (hint hint).
So why not plant your favorite veggies from the grocery store? After all, there's no magical distinction between, for instance, the beans in the bulk bins at your local natural foods store and the beans sold in seed packs.
However, not all grocery store food is created equal and there are some seeds which will not bear fruit, but many that will. Like with all seed-saving, it's important to use non-hybridized varieties. Hybridized means the seeds were produced in such a way that their first generation will bear fruit, but if you save seeds from that generation (for example, if you save seeds from a hybridized tomato at the grocery store) and if you plant them, they will not produce good produce.
How do you avoid hybrids? Anything labeled “heirloom” is not a hybrid. But there are many seeds, fruits and vegetables which are not labeled as “heirloom” but are in fact not hybrids and will grow robustly.
Which seeds will work
In the seed category, you can save seeds from heirloom (open-pollinated) tomatoes, peppers, melons and squash. Most legumes and pulses and grains (especially quinoa and amaranth) will grow marvelously in the garden. Intrigued by the color pattern on Jacob's Cattle beans? Take one or two from the bag and plant them!
Now, you probably wouldn't want to waste (that is, not eat) any part of a $6 tomato. But if one happens to go bad, that's great! Tomato seeds need to be fermented (which means they need to rot) in order to become viable. With plumbing, fermenting is pretty gross. With some seeds, it is necessary for germination.
For dry pulses, just plant them about an inch deep and water. Quinoa and amaranth generally do well sprinkled over soil, or lightly covered with soil, and watered. Melon and squash seeds can be planted as they are. For excellent information on saving and planting all kinds of seeds, refer to Suzanne Ashworth's guide "Seed to Seed."
Of course, you don't have to limit yourself to seeds. Pretty much every tuber you can buy will grow in your garden. Some that I've enjoyed are horseradish and Jerusalem artichoke (sunchoke). Others that will work are ginger, potatoes and yams. Especially when these tubers have been sitting around too long, have become shriveled and started sprouting roots or stems, why not plant them and maximize your returns?
Garlic is another one that will take well to the garden. Each head of garlic can be composed of 10 or more individual cloves and each clove can be planted and will grow a whole new head of garlic. Just remember that garlic is usually planted in the late fall when temperatures are going down, for a summer harvest.
Common spices like dill seed, mustard seed, caraway and nigella sativa will grow as well, if you want to grow them. The main limiting factor is age — how long have these spices been sitting on the shelf? They may have lost their viability.
In the world of tree fruits, you're usually discarding the seeds anyway. Growing them, however, can be a mixed bag as many fruits, like apples, will not grow true (which means if you plant a Pippin apple seed, it will probably grow a crab apple. If you plant a Red Delicious seed, it will probably grow a crab apple. You get the idea.). Growing a fruit tree from seed could be an edifying experience, but if you want good fruit-bearing trees it's better to buy good young stock from a nursery.
Which seeds might not work?
The reason why only heirloom stock of some types of fruits or veggies will work is that the hybridized varieties do not grow true. You're at the mercy of the seed companies for those seeds. Examples of other commonly hybridized produce include squash, melons and corn.
“Sprouted” seeds, nuts and grains are becoming very popular because of their health benefits and are becoming more ubiquitous in bulk sections (at least around Los Angeles). Seeds marked as “sprouted” will most likely not grow because the sprouting process starts the growth process but then cuts it off before the plant actually sprouts. Nipped in the bud, as they say.
Of course, any type of roasted or pasteurized seeds or nuts will not sprout because they are already dead.
Have you grown food from supermarket produce? Tell us about it!