Planting by the moon is one of the oldest of agricultural practices. It played a pivotal role in almost all ancient civilizations and cultures. For many thousands of years the moon has been worshiped and acknowledged for its influence on earth and everything on it.
The moon plays an equal role in the existance and creation of life on earth, as the sun. Just as we see flowers following the rise and fall of the sun; we see the moon influence the flow of water. The tides of the oceans are one of the most obvious signs of the moons influence on earth; but it is not restricted there, it also influences all things containing water.
If you work with people you'll probably notice a surge in out of the ordinary behaviour, when the moon is full. This is due to the increased blood flow through your body; especially to the head. Scientists have observed increased heart rates and alertness on a full moon in almost all patients. Next time your finding it difficult to sleep at night, have a look out the window, chances are it'll be a full moon.
Now onto the plants.

To me, moon or lunar planting is an integral part of gardening. It has been shown to increase, yeilds, growth, uptake of nutrients, health and vigor of plants, as well as decreasing, shock, stress, diseases, pests and deficencies.
Some ancient civilizations went as far as to only garden at night, under the light of the moon, with increased gardening at the appropiate stage of the moon.
How it works:Basically, the moon has two phazes, it is either waning or waxing. Waning is when the moon is getting smaller and waxing is when it is increasing in size. Simple.
When the moon is waning all the energy is pushing the water or sap (in plants) down, pushing with it the energy of the plant. When the moon is waxing all the energy is pulling the water or sap up, pulling with it the energy of the plant.
How can we use this in the garden?Easy. When you plant a type of plant, plant it on the correct phaze. Leafy greens should be planted whilst the moon is waxing (getting bigger). In-ground crops (potatoes, carrots, turnips, beets etc) should be planted when the moon is waning (getting smaller). Fruiting crops should be planted whilst waxing.
The moons energy is greatest at the full moon and new moon. Sprouts or sprouting greens should always be planted at a full moon as they will quickly germinate and grow long and leggy. For this very reason, planting anything on or around the full moon, other than sprouts, is discouraged.
Astronomy and lunar are hand in hand, and the signs also effect the influences of the moon. . . .
I could go on and on about lunar planting all night!!! But I'll leave it at the basics.
