Junior Member
Registered: 06-28-09 | If you set a fence post on a full moon it will heave out of the ground later. (in the winter?) If you dig a hole during a new moon you will have dirt left over when you fill it but you will have too little dirt if it is dug during a full moon. Some quick search notes: Google search "moon fence ground heave" http://www.deer-forums.com/dis...2877.html?1136563443"It is a proven fact that digging fence posts during the new moon will result in having dirt left over and post may heave from the ground. Digging during/after the full moon there may not be enough dirt to completely fill the hole back up but the post will settle tighter. " http://starryskies.com/article.../07/moon.phases.html"Even common farm activities, such as building a fence was done during the waning moon, as it was thought that if done then, the fence would not "heave" out of the ground during winter." http://www.diychatroom.com/f2/...ng-fence-post-41247/"HE would not set fence post on certain phases of the moon. I am here to testify that he taught me that there are certain days of the month when you can dig a hole, put the dirt in a bucket, place the same dirt back into the hole and not have enough to fill the hole. There were certain days of the month when you can did a hole, put the dirt in the same bucket, place the dirt back into the hole and have some left over-after tamping. That man could dig and set fence post on certain moon phases, using only dirt for backfill and you could not knock them over with an NFL lineman." |
Senior Member
Registered: 11-09-07 | this would definitely be interesting to try. there's a lot of gravity play involved. The moon causes the high tides, so i think it's very plausible that it has an effect on the dirt too... |
Senior Member
Registered: 02-17-08 | Fence post heaving has to do with the depth of the post and the frost depth. If the bottom of the pole is below the frost depth it will not heave. It has nothing to do with the moon.
How much dirt you get back in a hole is dependent on the compaction of the soil before and after digging. If the dirt is heavily compacted before digging and you break it up you will likely have difficulty getting it all back in. If the dirt is not compacted and when you put it back in you can easily compact the dirt going into the hole so that you do not fill the hole in when you place all of the dirt back in. Once again the moon has nothing to do with this.
The force on a 5 kg chunk of dirt from the moon's gravity is about 0.000166 newtons which is a weight difference of about 0.0169 g (Yes I know grams are a measurement of mass not weight and weight should actually be in newtons but I am putting it context that everyone should be familiar with) |
Senior Member
Registered: 01-12-09 | Sounds to me like someone was trying to prevent people from digging using the extra light provided by a full moon.
Before electrical illumination, full moons could increase the workday for several hours e.g. the harvest moon. However, I imagine that any work best done in bright light, like setting post straight would have suffered. The myth may have originated as a means of discouraging sloppy moonlight fence setting. |
Junior Member
Registered: 06-28-09 | quote: Originally posted by hawkmage:
Fence post heaving has to do with the depth of the post and the frost depth. ...
I would tend to agree with you, however I have seen evidence that would lead some to believe this. When I first heard this myth I was helping set posts around a friends yard. We started when the moon was full, setting 5 or 6 posts a day (dug by hand), and finished a week later. Six months later, during a BBQ, we noticed that the level of the concrete around the first 10 posts was about one inch above ground level and the rest were at or slightly below ground level. All the holes were dug to 20-24" below grade and the frost line in our region is only 15". This does not mean the moon had a hand in this, just that there was a myth stating as much and the evidence fit in to the myth which reinforced the idea. This is not directly tied to the tidal forces of the moon as it does not happen all at once on a full moon but the effects are noticed over time. One possibility is that during a full moon the water table of an area might be at its highest which would affect the density of the soil. It could be something simple like the walls of the hole are smoother which allows repeated tidal forces to wiggle the post out as opposed to a rough dirt wall locking it in to place. This myth seems closely tied to the density of the dirt at the time it is dug. For Shannonlove, although a full moon event is technically instantaneous (passing from waxing to wanning), it is typically considered to last for one or two day before and after the actual point of fullness. A full moon is a daytime event as much as it is a night time event. I do recognize the humor of your statement though :-) |
Junior Member
Registered: 06-28-09 | Keep in mind that the moon's gravity does not move ocean going ships of all sizes up and down many feet as it passes overhead but it does move the water which brings the ship along with it. If this myth has any truth to it, it is almost certainly caused by tidal forces on the water table or the soil. The crust of the earth moves side to side and up and down every 12 hours with the tide anywhere from 50-500mm. http://en.wikipedia.org/wiki/Earth_tide |
Junior Member
Registered: 06-25-09 | I would be interested in seeing the mythbusters prove or disprove this myth. Although I must admit I'm a little skeptical. |
