Great Mysteries of the Garden

[patandchickens]

So, how come when you dig a hole in the ground normally, like to repair a water line, you end up with extra dirt left over at the end (assuming you put it on a tarp or whatever, rather than letting it lose itself in the grass)...

...but when you dig a hole in the garden to insert a new plant, which has a volume-occupying rootball already fer cryin' out loud, you usually end up with too little dirt to fully fill in around it?



Pat, who actually does know the answer (="because life is unfair")

 

[DrakeMaiden]

NO, that only happens when you don't have access to extra soil. If you have plenty, then you will always end up with an extra little pile of soil after planting.

 

[patandchickens]

"Extra soil"? Is that kind of like a surplus of finished compost? A glut of Rolls Royces in the driveway? Too many winning lottery tickets?

LOL

Pat, on sucky clay soil with *never* enough of it in good shape to be moving around, although I do steal from the heavily-amended-and-tended veg garden soil on occasion

 

[DrakeMaiden]

Chincing the veggie patch are we!!!

I only have extra soil to kick around when I dig in pavers or pathways . . . or trenches, oh, or ponds! I'm working on digging a trench/temporary pond for my ducks, because when it rains they always gravitate to the puddle in the middle of the driveway and it drives me nuts when people come over and actually [imagine this!!!] drive through the puddle!!!!!!!!!! The nerve of some people! :/

 

[beefy]

garden gnomes?

 

[S0rcy]

When you dig a hole for a line you have added air to the structure. It is no longer as compact as it used to be.

I'm not sure about the rootball, I've always had extra soil left over.... Perhaps is how big/wide you dig the hole or how you break up the dirt.

 

[silkiechicken]

Chincing the veggie patch are we!!!

I only have extra soil to kick around when I dig in pavers or pathways . . . or trenches, oh, or ponds! I'm working on digging a trench/temporary pond for my ducks, because when it rains they always gravitate to the puddle in the middle of the driveway and it drives me nuts when people come over and actually [imagine this!!!] drive through the puddle!!!!!!!!!! The nerve of some people! :/

Talk about puddles... when this 8 inches of freak snow melts, the puddle that forms in our drive way is going to be HUGE. On a heavy rain it's oh... 20 ft by 30 ft...

 

[Rosalind]

Because when you are digging up a hole for a plant, chances are its previous occupant was grass. Most of the dirt is still stuck to the sod you removed, and the volume of air added is not very great. Whereas when you are digging a hole for a water line, you are supposed to dig below the frost line.

Mathematics of Dirt Teleportation:

Let the density of soil before digging, and the density of what you are putting in, D0 = 1 kg/100cm^3
Let the density of soil after digging and re-filling, D1 = 0.95 kg/100cm^3
Let the surface area of hole, SA = 1m^2, about the size of a hole for a bush
Let depth be represented as L for length
Let the depth of the sod = 8 cm, we'll be generous

For each hole dug, you will lose soil = SA x 8 cm = 80000 cm^3.
The volume of the hole = 1m^2 x L

Pre-digging, the mass of soil in the hole can be calculated as 1m^2 x L x D0

Post-digging, the amount of soil in the hole can be calculated as 1m^2 x L x D1 - (80000cm^3 x D0) + (volume of what you put in x D0).

1m^2 x L X D0 = (1m^2 x L x D1) - (80000cm^3 x D0) + (volume of rootball x D0)

After correcting for units, you can see that the equation is generally linearly dependent on L.

10000L = 9500L - 80000 + (rootball volume)

500L = rootball volume - 80000

L = rootball volume/500 - 160

We can see from inspection that if our rootball volume = the volume of sod we removed, there will be no difference in residual dirt. However, there should be two solutions to this equation. At L = 160cm, rootball volume = 0, therefore at 160 cm depth there will be neither extra dirt nor insufficient dirt to re-fill the hole, in absence of anything you are trying to plant.

 

[justinszoo]

Well.......there is a technical answer if I ever saw one.

I guess if u ask u shall recieve.

 

[whatnow?]

That's pretty good, Rosalind. I thought about throwing in some geotech stuff, but I now know that Pat is way too educated to bluff.