How do you dig a post hole in dry sand????

Hey everyone,
I finally got my little permaculture piece of heaven. Sadly, it is mostly beach sand. (But had other aspects worth dying for) Sadly, we are 300 miles from the actual beach.

I need to create almost 100 fence post holes on the property, about 3' deep. I have a tractor and a 12" post hole PTO attachment.
It digs just fine. The problem is that when I dig a hole 4' deep, and pull out the auger, the hole just collapses in on itself. The area where the fence posts are going currently has no vegetation on it.
It hasn't rained in 5 weeks, so the sand is described as "sugar sand". There is just no structure to the "Soil" (If you can call it that) at all. It just doesn't hold.

Aside from waiting for rain, and I am quite impatient, or wetting the ground with a tremendous amount of water, are there any ideas?

thanks,

Richard

Maybe try a piece of pipe just larger than the auger as a sleeve for the hole? T posts might work, just drive them into the sand with a t post driver.

Jd Gonzalez wrote:Maybe try a piece of pipe just larger than the auger as a sleeve for the hole? T posts might work, just drive them into the sand with a t post driver.

Yeah, Tee-Posts are nice, but in this case I have to use 2 & 3/8" pipe. And these have to be pretty solid, so I don't feel comfortable just driving them in. I want to drop a bag of cement into each hole. It is in sand, after all.

In other words, I don't need alternatives to digging a hole. A 32" hole is what is called for.

As for a sleeve for the auger, any idea how to find a 13" sleeve?

Would that work in this case?

rihard

Wet the sand. It holds its shape much better when wet.

Edit- Just read it again. You want to avoid wetting. Should you change your mind, drive lengths of pipe, then fill with water. This directs water to exactly where needed.

We always just use a pounder instead of holing them. A hydraulic post pounder is fairly quick in the overall scheme of things. Is this an option for you?

Agree with Stephan on this. Drilling a hole in sand is a Sisyphean task, until you have a large crater and destabilized sand to try and hold you post in place. A hydraulic post pounder would leave the sand "intact" and would even form a compressive layer around the post so you wouldn't need to concrete it in.

If that isn't feasible for you, then a big hole, stabilization of the post with sticker wood (board or what not to hold the post upright and level) while your concrete dries, and then backfilling.

R Hasting wrote:
In other words, I don't need alternatives to digging a hole. A 32" hole is what is called for.

In The Fellowship Of The Ring Frodo famously says "Go not to the elves for counsel, for they will say both no and yes." Our local version of this ought to be "go not to permies.com for advice on how to do a thing, for they will tell you at length how to do something else entirely."

I'm afraid it's the permies.com superpower. That hard thing you want to do? People imbued with permaculture thinking are much more likely to have some clever scheme for doing an easier thing instead, or possibly even for doing nothing and calling it "more sustainable". I've been on the receiving end of this enough times to know how infuriating it can be, and yet it really is the permaculture way.

Are posts driven into three feet of sand truly not stable without concrete? Because that sounds like a much easier approach if it would serve.

Bless you for the post Dan...

I get myself into "hot water" too often trying to answer folks questions...like this one, for exactly the reason you just cited. So, I have come to the conclusion of:

Don't post anything...(not my nature or very helpful in my view)

or...

Per the wise counsel of Dale H...(thank you Dale) make a statement...move on...

So with your opening Dan...here goes...

I won't belabor how many post I have placed (or helped place) in this lifetime, and how often that was in pure beach sand...(probably pushing someplace between 700 and 1000?)

Keyword..."pushing."

"Pile driving" is the dominate way posts are placed (to meet PE specification of "resistance by friction") in any "loose or open grained soil types." This is how Venice was built, this is what many stone ramparts/buttresses to bridges in rivers rest on...and it is how most "beach houses" on stilts get there foundation built...Pile driving is simple the best method generally.

The reason??

1. Holes "dug" in sand cave in...making place a post in the hole very frustrating...

2. Resistance by friction is superior in these soil types...


Now, with that stated...Yes, I have "dug in post" in sand soils because "pile driving" is not really accessible all the time (though generally faster and more cost effective if doing more than 20 posts.)

If digging by hand we employ batter boards that slide into the hole as we dig.

If "auger digging" we set up a plastic pipe sleeve (24" to 28" for a 32" auger bit) that slides down the hole as it is excavated. Then the post is place in the hole (there is simply no reason for concrete at all for it adds nothing to the post stability and often just rots it out quicker...not to mention that portland cements contribute 20% of the pollution we breathe in...)

Spin the tractor around and off your bucket clip a chain to the pipe sleeve and extract it from the hole. Cave in is fine at this point and all that need to be done is help along the process, pack the area around the post further, and if need be in a few months (or years) drive in "post wedges." This is a traditional method for straightening and "firming up" posts really tight.

I will presume that these are not chemically treated post and of some naturally rot resistant species...If not...well PT is not a permie material and I will leave the PT issue for others to address.

That is my 2¢ and I hope it was of some help...

Dan Boone wrote:

R Hasting wrote:
In other words, I don't need alternatives to digging a hole. A 32" hole is what is called for.

In The Fellowship Of The Ring Frodo famously says "Go not to the elves for counsel, for they will say both no and yes." Our local version of this ought to be "go not to permies.com for advice on how to do a thing, for they will tell you at length how to do something else entirely."

I'm afraid it's the permies.com superpower. That hard thing you want to do? People imbued with permaculture thinking are much more likely to have some clever scheme for doing an easier thing instead, or possibly even for doing nothing and calling it "more sustainable". I've been on the receiving end of this enough times to know how infuriating it can be, and yet it really is the permaculture way.

Are posts driven into three feet of sand truly not stable without concrete? Because that sounds like a much easier approach if it would serve.

Dan, So true here at Permies...

These are 13g 2 3/8" steel posts, and if I could design them so that I could sink them 48" I probably wouldn't bother with concrete...
But I only got 32" and these are for a 6600 SF greenhouse.

Ok, so my son came up with this solution. It works!!!
We have water available. I place the post hole digger into the ground and turn on the pto. My helper sprays it with water. I will try to post a video of it in the next couple of days.

But this works... Hooray!

R Hasting wrote:
But this works... Hooray!

That's awesome. I'm glad you found a way. And, yeah, driving them would probably require longer posts than it sounds like you have.

That's one off the reasons the "permies way" can be infuriating, actually. "Life gave me lemons, how can I make lemonade?" "In the long run, you'll be better off growing apples and making cider." "But my kitchen, it's full of lemons today!"

I’m trying to dig a 2’x3’ hole in the sand in my backyard in FL to drop a sump basin in for runoff surface water.(later to be pumped out) Sand just caves due to high water table..any thoughts? I feel like i’m swimming upstream..thanks

Hi Mark,

First, welcome to Permies.  Consider building walls to keep out the sand and set it on top of the sand. A piece of culvert would work as well.  Dig out from inside it so that, as you dig, the culvert/box will drop down.  This is one of the methods that used to be used to dig wells.