A seed is such a tiny package, but within it one of the great mysteries of the universe lies dormant, ready to unfold with just the slightest prodding. Curled into a seed is a force with more than the power of a locomotive, and greater than that created by splitting atoms. It's the force of life itself.

And seeds are the vehicles for this force which makes life happen. They're adaptable, tenacious, prepared to travel great distances and in some cases extremely mobile, and they have the ability to remain dormant for years, waiting until the conditions are right for life.

Seeds are nature's insurance against calamity. They're produced in such enormous numbers that, just by chance, some of them are bound to make it. And they have nature's ingenuity behind them. Some seeds have even developed interesting ways of getting people to work for them.

Garden seeds have this part worked out. They don't need wings or skills to find the right location for growth, simply because they've done such a good job of making their place in the world. They've spent centuries training people to plant them and tend to their needs.

Even weeds have people working for them. Dandelions have enchanted children to blow their silky parachutes of seed to the wind. Maple seeds, so appealing as stick-on elf noses, have persuaded children to play with them - and release their round seeds from the propellers that carried them, like miniature helicopters, to the ground.

Burdock seeds grow in sticky burrs, which attach themselves to animals - from cats to men to bears - and hitch rides around the world. Marijuana seed makes canaries sing, and it used to be included in birdseed until folks discovered that the birds were seeding the fields and roadsides with it. Now it's no longer in birdseed, but young people have taken on the job of scattering its seed.

Tomato seeds are so hardy they can survive the human digestive tract and sewage treatment. And seeds - thousands of years old, but still viable - have been found in ancient tombs.

The seeds of jewelweed or wild touch-me-not are highly mobile. They ripen inside pods that explode when the seeds are ready, scattering them with strong force. And, on a windy fall day, you can see the silky seed of milkweed floating by on the currents.

Seeds are so mobile, in fact, that most of America's weeds are not native, but imported from Europe. Not too many people imported weed seed on purpose, but it came anyway - in soil, fur, packing material, animals and animal feed, in pants cuffs, socks, shoes and any other way it could catch a ride. Weeds settled America with the Europeans.

And one of the names of the common plaintain is white man's footprint. Indian legends say it only grew where white men had walked. It started in white settlements and quickly spread to become one of the hardiest weeds, capable of thriving between the cracks of city sidewalks.

But seed was easier to gather and spread back in those days when seeds ran true. Today, many garden seeds are hybrids, and they don't run true. That means that if you save seed from hybrid vegetables, you won't know what you're going to produce, and you may not get anything at all. Hybrid corn, for instance, produces only sterile seed.

But if you're growing old-fashioned, unhybridized crops, you can save the seed of the plants that have the qualities you're seeking.

Mix tomato seeds and pulp with a little water and let them ferment a few days, then rinse, dry and store them. Let other seeds ripen in the garden. And remember that biennials, like beets, carrots and cabbages, don't set until the second year.

And, if you really get into saving old-fashioned seed, get in touch with Kent Whealy, RFD 2, Princeton, Mo. 64673. He runs The True Seed Exchange, and connects gardeners across the country who have old-fashioned seeds to share.