In this age of precision farming and global positioning, there is still one ancient satellite that continues to provide farming information to many people: the moon.

Farming and gardening by the signs, or phases, of the moon probably goes back to the days when dinosaur bones were tillage tools.

But the practice, unlike those bones, hasn't become a relic. And many believe the reason it hasn't is that it works. Therein lies an age-old argument, which won't be debated here.

But just how do you know when the signs are right?

The lunar month is divided into four phases or quarters. The light of the moon is the 14-day period (first and second quarters) when the moon is growing from the new moon to the full moon. The dark of the moon (third and fourth quarters) is the following 14 days -- from the full moon to the next new moon.

Some folks even like to get more specific and plant by the signs of the moon. These change about every two and a half days.

Examples are when the signs are in the reins, bowels, breast, heart, knees, thighs, head, etc. There are twelve such signs, and you'll have to refer to an almanac to see exactly when they change.

Even with an almanac, it may be hard to tell exactly when the signs change, since each almanac is based on a particular time zone.

Remember, they change about every two and a half days. As a rule, most people skip the first day of a sign just to avoid this confusion.

The signs are associated with the signs of the zodiac. For instance, Leo is ruled by the heart and is a barren sign. Cancer is ruled by the breast and is a fruitful sign.

So what are these phases and signs used for? And how do you use them? Here are some age-old rules.

Prepare the soil and cultivate during barren signs. Prepare the soil in the light of the moon, and cultivate in the dark of the moon.

Why? The theory is that in the light of the moon, the moon is growing. This will cause the soil to remain loose and be easier to turn. The barren sign, too, indicates a time when weeds are vulnerable to attack and may more easily be killed.

Always fertilize during a fruitful sign. Apply chemical fertilizers in the light of the moon and organic fertilizers in the dark of the moon.

Irrigate during one of the water signs, Scorpio (the secrets) or Pisces (the feet). Always water in the light of the moon (when the moon is growing larger) since you're also watering to make your fruits and vegetables grow larger.

How about planting? Well, plant crops that produce fruit aboveground in the light of the moon. Plant crops that produce fruit underground, such as potatoes, in the dark of the moon.

The first quarter is best for planting crops that produce seed outside the fruit. The second is best for crops that produce seed inside the fruit. The third is best for planting crops that grow underground.

Avoid planting in the fourth quarter if you can. And, of course, always plant in a fruitful sign (Cancer, Scorpio, Pisces, Taurus, Capricorn, Libra).

It's really quite easy to coordinate the signs and the moon's phases to follow the proper timing for your farming or garden practices.

Does following the most original of the earth's satellites help grow a better crop? That's something you may decide after you've tried it.