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Sunken beds in hardpan caliche?  RSS feed

 
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Hi, I'm new here, so pardon if I'm not doing something right.

I'm planning to start a garden, and I've been reading various websites, watching videos, etc. on how to grow your veggies with the most nutrition. I live in the South in a particular spot that gets very little rain, especially in the summer when temperatures reach 100 degrees. The soil on our slope of the hill is virtually non-existent. It's rocky and is solid caliche hardpan below the 6 inches of top soil. The hardpan goes as deep as you can get, hundreds of feet down. Moreover, in this area junipers, aka cedar, are abundant, and they have a nice and soft dirt collecting under them with plenty of organic matter. Last year I've put up some raised beds that I made myself and loaded them up with the cedar dirt that I robbed from the trees around the property (4 acres). Turns out that cedar dirt inhibits plant growth! Nothing could grow in those beds.

I'm not giving up, however, and am fully prepared to conquer mother nature with dozers and premium soil mixes.

I've been reading about the type of gardening that's appropriate for the climate here, and it seems that sunken beds are the best for the heat and the lack of rain. Raised beds tend to absorb heat from the air, plus the south side gets heated by the sun, and they dry up faster. So, raised beds are actually a terrible idea for the south, since they get hotter and dry out faster. Sunken beds seems to be the natural choice as the plant roots will be kept cooler and the water will be preserved better.

But sunken beds in caliche? Every time I want to plant a flower I have to break the soil with a pick axe, and a good 3 ft round hole that's a foot deep takes me two days of hard work. A friend of mine had to come help me break through the soil with the same machine used to break up asphalt and concrete so I didn't break my back just to plant some nice flowers around the house. When I watch videos where people dig their soil with shovels, I laugh. Not in my yard. Double digging? An 8x4 garden bed double dug with a pick axe will take me about a week to do. And I have 12 beds planned.

And yet I'm not giving up. I have a contractor come look at it and see how he can help me with heavy machinery. In the mean time, if any of y'all have advice for me I'd appreciate it.
 
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Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
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First thing to know about Caliche is that it is water impermeable.

That means, if you do sunken beds, the Caliche will need to be broken up over a far greater area than what the garden beds will take in.
Jack hammers and demolition hammers are the norm for breaking up Caliche.
Once this stuff is broken down into small pebble sizes it can be amended with compost and or wood chips.

As you found out Cedar (actually in your area it is most likely to be juniper, commonly miss named cedar) is allopathic, to combat the allopathy fungi work wonders at removing the compounds the "cedar" trees sent into the soil as exudates.
Expect it to take a year to remediate cedar soils to the point where vegetable and other plants will be able to grow.

Gardening in Caliche can be done, I have a friend who is doing it quite well, it just takes a lot of time.
The most organic method of decomposing Caliche is to use vinegars, Caliche is Calcium carbonate and vinegar will dissolve it just as it does in high school chemistry class. (Remember the rock that bubbled when vinegar was poured on it?)

Redhawk
 
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I am really glad Redhawk showed up to address this issue. His soil primer is really useful.

Caliche is usually (always?) basic. While I would always test the soil, I am pretty sure you'll need to adjust the pH.

As mentioned, you're going to need more than just the bed space broken up. Do you have any pioneer weeds that eke out an existence on the caliche? Maybe they could be encouraged to do the work of assisting to break it up, should any of their root systems work for that.

-CK
 
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Im curious if you have noted where the water pools, or runns, when the rain does come.
 
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I use a hammer drill for a few mins to make a small plant pot sized hole and then in the bottom of that a 1 metre long masonry drill goes in for roots to follow water down. Takes a few mins and then desert trees grow successfully. I've even got a few hybrid poplars going with this method but they need water at least a couple of times a month in summer.
 
pollinator
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This thread is located below your thread in "Similar Threads".  In case you have not seen it, it may contain some helpful info ...

https://permies.com/t/53929/Successful-annual-vegetables-Central-Texas

It will not help you dig the hole but it may offer suggestions on how to fill the hole.

Do you have Live Oak, Shin Oak or other oak trees?  You will find usable soft dirt collecting under them with plenty of organic matter.  This leaf matter is good for perennial plants.

If your property is large enough you may be able to find pockets of clay soil.  I am not sure how to tell you how to find it, maybe by looking for pockets that do not have lots of rock.  Our clay pit was about 5'x5' and 3' deep.  It no longer contains any clay as we used it to make our raised beds but it now would make a great sunken garden. Since you plan to have a contractor come out he may be able to help you find a pocket.
 
Anne Miller
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Have you researched using  "Zai Holes"?

Here are some threads:

https://permies.com/t/38879/Sinking-Sand

Bill McGee wrote:

My soil is a very fine silt and land is on a slope.  Inspired from this site  I do a modified "post-hole dug zai pit" for each plant
1. Shovel off top soil layer and save
2. Use post hole digger and go 18" down (or as needed for roots of plant)
3.line bottom with biomass gley (leaves or paper, etc) to slow water absorbtion
4.  Mix in mature compost with soil removed. At top mix top soil and organics
5.  Leave a small basin so it collects water
6.  Build a small semi circle basin on the down slope side to also help collect run off rain
7. Plant

It might be efficent to compost directly into the "PH zai pits" and save a handling step.



https://permies.com/t/36823/restoring-land-permaculture-methods-photos#287561

Jennifer Wadsworth wrote:I live in a hot, dry climate here in Phoenix, Arizona.  I have also lived in Kenya, Somalia and Lesotho. 

Here are some resources that may help you - some of them are happening close to you:

Farmer Managed Natural Regeneration:  http://fmnrhub.com.au/

Niger has had some fabulous success with reclaiming desertified lands with FMNR:



Zai Pits and the story of Yacouba Sawadogo - the "Man who Stopped the Desert"

How to build Zai Pits:  http://en.howtopedia.org/wiki/How_to_Start_Culture_in_Zai_Holes





 
Tatiana Trunilina
Posts: 11
Location: Central Texas
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Thank y'all for your helpful replies! The contractor said he'll take the top layer off and mix it with manure, and I want to add some mulch to mix into the soil, but I'm still deciding which mulch to use. I decided not to do sunken beds, just soil-level beds, since I don't have that much depth to do sunken beds. I can only add dirt and raise the whole garden by about 6 inches.

Bryant RedHawk wrote:First thing to know about Caliche is that it is water impermeable.

That means, if you do sunken beds, the Caliche will need to be broken up over a far greater area than what the garden beds will take in.
Jack hammers and demolition hammers are the norm for breaking up Caliche.
Once this stuff is broken down into small pebble sizes it can be amended with compost and or wood chips.

As you found out Cedar (actually in your area it is most likely to be juniper, commonly miss named cedar) is allopathic, to combat the allopathy fungi work wonders at removing the compounds the "cedar" trees sent into the soil as exudates.
Expect it to take a year to remediate cedar soils to the point where vegetable and other plants will be able to grow.

Gardening in Caliche can be done, I have a friend who is doing it quite well, it just takes a lot of time.
The most organic method of decomposing Caliche is to use vinegars, Caliche is Calcium carbonate and vinegar will dissolve it just as it does in high school chemistry class. (Remember the rock that bubbled when vinegar was poured on it?)

Redhawk



Yes, it is Juniper, and it's a local pest for multiple reasons.

I like the idea of using vinegar! How would you use it though? Dissolve some in 5 gallon buckets and pour all over the place? And then, after a couple days try it with a masonry hammer. The problem is I don't have that much room to break up the caliche around the garden. On one side there's a fence to out neighbor, on the other there's a hill that we're going to cut partially to fit the garden, on the third side there's a slope with trees that's mostly solid rock, and only the fourth side of the garden I can probably work on the caliche beyond the garden's boundary. I wouldn't say that our caliche is impermeable, the water goes down within a day after a rain.

And what is this soil primer Chris Kott is talking about?


Chris Kott wrote:I am really glad Redhawk showed up to address this issue. His soil primer is really useful.

Caliche is usually (always?) basic. While I would always test the soil, I am pretty sure you'll need to adjust the pH.

As mentioned, you're going to need more than just the bed space broken up. Do you have any pioneer weeds that eke out an existence on the caliche? Maybe they could be encouraged to do the work of assisting to break it up, should any of their root systems work for that.

-CK



Hmm, we have very little grass, and it'd take a lot of time to do it that way. I'd need to maybe feed it with manure and mulch. Even trees can't break through. I heard sunflowers may be useful, so I'm gonna plant some within the garden to see how it works. Along with every other cover crop that is known to break up hardpan.



William Bronson wrote: Im curious if you have noted where the water pools, or runns, when the rain does come.



The water runs off the ground and doesn't get absorbed well. We have a few holes left by the guy that did the septic after he dug a few trial holes (about 4 ft deep), and they fill up with water which stays in them for a few hours.


Steve Farmer wrote:I use a hammer drill for a few mins to make a small plant pot sized hole and then in the bottom of that a 1 metre long masonry drill goes in for roots to follow water down. Takes a few mins and then desert trees grow successfully. I've even got a few hybrid poplars going with this method but they need water at least a couple of times a month in summer.



Yeah, I'm planning to do that for fruit trees as well. But for a garden a wide area needs to be broken up.


Anne Miller wrote:This thread is located below your thread in "Similar Threads".  In case you have not seen it, it may contain some helpful info ...

https://permies.com/t/53929/Successful-annual-vegetables-Central-Texas

It will not help you dig the hole but it may offer suggestions on how to fill the hole.

Do you have Live Oak, Shin Oak or other oak trees?  You will find usable soft dirt collecting under them with plenty of organic matter.  This leaf matter is good for perennial plants.

If your property is large enough you may be able to find pockets of clay soil.  I am not sure how to tell you how to find it, maybe by looking for pockets that do not have lots of rock.  Our clay pit was about 5'x5' and 3' deep.  It no longer contains any clay as we used it to make our raised beds but it now would make a great sunken garden. Since you plan to have a contractor come out he may be able to help you find a pocket.



We have very little leaves available, even though we do have a few oaks. The problem is they all get washed out with rains. And we've already looked at the whole lot a few times with different contractors, there's no clay here.



Anne Miller wrote:Have you researched using  "Zai Holes"?

Here are some threads:

https://permies.com/t/38879/Sinking-Sand

Bill McGee wrote:

My soil is a very fine silt and land is on a slope.  Inspired from this site  I do a modified "post-hole dug zai pit" for each plant
1. Shovel off top soil layer and save
2. Use post hole digger and go 18" down (or as needed for roots of plant)
3.line bottom with biomass gley (leaves or paper, etc) to slow water absorbtion
4.  Mix in mature compost with soil removed. At top mix top soil and organics
5.  Leave a small basin so it collects water
6.  Build a small semi circle basin on the down slope side to also help collect run off rain
7. Plant

It might be efficent to compost directly into the "PH zai pits" and save a handling step.



https://permies.com/t/36823/restoring-land-permaculture-methods-photos#287561

Jennifer Wadsworth wrote:I live in a hot, dry climate here in Phoenix, Arizona.  I have also lived in Kenya, Somalia and Lesotho. 

Here are some resources that may help you - some of them are happening close to you:

Farmer Managed Natural Regeneration:  http://fmnrhub.com.au/

Niger has had some fabulous success with reclaiming desertified lands with FMNR:



Zai Pits and the story of Yacouba Sawadogo - the "Man who Stopped the Desert"

How to build Zai Pits:  http://en.howtopedia.org/wiki/How_to_Start_Culture_in_Zai_Holes








Wow this is a really good idea! I'll probably do this throughout the lot to encourage vegetation, since it looks pretty miserable right now. Our entire lot is on a slope, so these zai holes will work pretty good I think! this way I can prepare the spot for the fruit orchard that we're planning in a few years.



Thank you guys so much!
 
Tatiana Trunilina
Posts: 11
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This is what I'm talking about when I say caliche:



This man stripped the grass and this was under it. We have a thin layer of topsoil 4-6 inches, 8 inches under oaks in densely wooded areas, and under that it's all pretty much solid concrete just like on the video. I think I need to dig chimneys like he did to drain excess water and fill them up with composted mulch.
 
Bryant RedHawk
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Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
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quest for supersoil This is the second part of my soil series in this forum.

What we need to know about Soil This is the first thread of my soil series in this forum

Redhawk  Together they make up a fair "Soil Primer"
 
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I assume the vinegar is sprayed or allowed to spread in whatever shallow trench that you can provide. You can test by pouring a gallon of white vinegar into a test hole, and watch for the fizzing, which shows the chemical reaction. If the vinegar works, you will be able to break up a layer of dirt that you can then use to create a soil, using your compost, manure, or other amendments. Get a bunch of pH soil testing strips to keep track of how your soil treatments are affecting the pH of your soil. If the vinegar makes your soil too acidic, you can try adding some ground up gypsum board (drywall) or other base pH material to neutralize your soil to the desired pH. Starting small, and seeing what works could save you a lot of work in the long run. Try to get the plants and animals to do most of the hard work for you by doing what they do naturally.

If you must hurry to get up and running in a single season, you may have to start with Zia pits for each plant, then infill between established plants as you progress, eventually ending up with the first row of your planting bed.

(I am not a plant-person, so you'll have to do some research to determine which plants might work in your area.) For your orchard, consider planting an upper-canopy tree to nurture and shelter your orchard trees and to pull up sub-surface nutrients. Think in terms of establishing a forest-garden guild of companion plants.

You may not be able to create a traditional-looking planting bed from the start, but perhaps you can let your plants do the work for you. It may take a series of steps to prepare the entire area to be planted. I would start with some test holes to see what works.

You may try to establish some sort of litter-producing ground cover first, to form a habitat for useful microbes, earthworms, and dung-beetles to take hold. Plant some deep-rooting cover grass, such as big bluestem or a clumping type of deep-rooting grass. Remember, you are in this for the sustainable long-haul, so you may have to change your expectations for which yields you can work with along the way to get you to your eventual goal. Be aware that if you do end up achieving some sort of sunken pit, you'll need to allow for the run-off (both surface and sub-surface) to avoid ponding and drowning out your plant's root systems after it rains. If you can utilize the property's natural slope, so much the better. Otherwise, you'll have to allow for the water to sink below the level of the roots. As I recall, Texas can get some pretty serious rain and floods at times. One extreme possibility is to install some 4" perforated pipes underneath your planting beds and feed them into a sump-pit, where you can pump or drain the excess water out from beneath your flooded beds. Think in terms of an absorption field such as one might use for a septic system. Ideally, any such extreme measures would be as a last resort, and whatever method you use should use as little energy as possible.

Reading your replies, I see that you do have a slope at your disposal, so you could allow any water that would fill up your zia pits to run out to daylight.  Just leave the downhill side of your zia pit open to the slope below. You wouldn't need any pipes to do that. Water flows downhill, even if it is underground. Just plan for adequate drainage.
 
Posts: 110
Location: Gaines County, Texas South of Seminole, Tx zone 7b
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I feel you pain I am up here in Gaines County Texas and know what you are talking about with hard pan.  For the most part I been letting my yard get messy like this picture and once it gets tall and seeds I come through with a weed eater and cut it down and then let it grow up again.  I have found just by gathering up this material and laying down as stray builds up my yard better over time.  These pictures are an area dug this year and what the grasses did with water collecting in from rains this year on my caliche area.

Also if you want to see more of what I am doing you can go the following link and see other tests i am doing.  I am tempted to go across the draw and see what the guy raising sheep is doing with the manure and see if I can take that for my land.  Just Getting the land covered I notice that by the next year I am able to work it a little more.

https://permies.com/t/71712/Everjams-Farms-Gaines-County-Texas
20171115_111307.jpg
[Thumbnail for 20171115_111307.jpg]
Area around this Hole By end of August with hole below just filling with water from the few rains this year.
20170612_192506.jpg
[Thumbnail for 20170612_192506.jpg]
My Caliche Hole dug out this June 2017
 
Tatiana Trunilina
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Bryant, I'm currently reading your threads, very informative!

Update:

We have a contractor coming to build our garden. It's going to be an enclosed area with 8 ft tall fence, covered all around with mesh to keep critters away, except the good ones. We have several kinds of hungry critters who can decimate the entire garden in one night: deer, rabbits, raccoons, armadillos, opossums, foxes, mice, snakes, coyotes, sometimes wild hogs, and various bugs, but not as much. There is no fencing around our property, so we at least want to fence in the garden with metal wire fence that's going to be partially under ground.

Because of that, the garden itself will be a limited area, so we can't really employ some fancy techniques like zia holes in it, due to just not enough space to grow enough food. What we're planning to do is incorporate good dirt, (manure compost + rice hull compost + granite sand + gypsum) available at a local soil supply place, with the existing topsoil, hopefully to 4 inches. The contractor said he will loosen up some of the caliche with his dozer. That's just for the vegetable garden. Let's see how that works. I'm also planning to innoculate the soil with various microbes, like make compost teas, buy fungi supplies, etc.

For all trees, we're planning to dig holes with a mini excavator and fill them with good soil, especially for fruit trees, but that's a project for next year probably. We also need to provide irrigation to each tree.


We are looking at different ground cover options because we don't like to mow the grass here on the steep slopes. I don't know how groundcover would affect soil health, however.


Mark Kissinger wrote:I assume the vinegar is sprayed or allowed to spread in whatever shallow trench that you can provide. You can test by pouring a gallon of white vinegar into a test hole, and watch for the fizzing, which shows the chemical reaction. If the vinegar works, you will be able to break up a layer of dirt that you can then use to create a soil, using your compost, manure, or other amendments. Get a bunch of pH soil testing strips to keep track of how your soil treatments are affecting the pH of your soil. If the vinegar makes your soil too acidic, you can try adding some ground up gypsum board (drywall) or other base pH material to neutralize your soil to the desired pH. Starting small, and seeing what works could save you a lot of work in the long run. Try to get the plants and animals to do most of the hard work for you by doing what they do naturally.

If you must hurry to get up and running in a single season, you may have to start with Zia pits for each plant, then infill between established plants as you progress, eventually ending up with the first row of your planting bed.

(I am not a plant-person, so you'll have to do some research to determine which plants might work in your area.) For your orchard, consider planting an upper-canopy tree to nurture and shelter your orchard trees and to pull up sub-surface nutrients. Think in terms of establishing a forest-garden guild of companion plants.

You may not be able to create a traditional-looking planting bed from the start, but perhaps you can let your plants do the work for you. It may take a series of steps to prepare the entire area to be planted. I would start with some test holes to see what works.

You may try to establish some sort of litter-producing ground cover first, to form a habitat for useful microbes, earthworms, and dung-beetles to take hold. Plant some deep-rooting cover grass, such as big bluestem or a clumping type of deep-rooting grass. Remember, you are in this for the sustainable long-haul, so you may have to change your expectations for which yields you can work with along the way to get you to your eventual goal. Be aware that if you do end up achieving some sort of sunken pit, you'll need to allow for the run-off (both surface and sub-surface) to avoid ponding and drowning out your plant's root systems after it rains. If you can utilize the property's natural slope, so much the better. Otherwise, you'll have to allow for the water to sink below the level of the roots. As I recall, Texas can get some pretty serious rain and floods at times. One extreme possibility is to install some 4" perforated pipes underneath your planting beds and feed them into a sump-pit, where you can pump or drain the excess water out from beneath your flooded beds. Think in terms of an absorption field such as one might use for a septic system. Ideally, any such extreme measures would be as a last resort, and whatever method you use should use as little energy as possible.

Reading your replies, I see that you do have a slope at your disposal, so you could allow any water that would fill up your zia pits to run out to daylight.  Just leave the downhill side of your zia pit open to the slope below. You wouldn't need any pipes to do that. Water flows downhill, even if it is underground. Just plan for adequate drainage.



Yeah, we have a slope, so I think the problem in our garden will be with the water running on top of the hardpan and not absorbing through.

The vinegar idea sounds great! I'll see where I can apply it.


James Everett wrote:I feel you pain I am up here in Gaines County Texas and know what you are talking about with hard pan.  For the most part I been letting my yard get messy like this picture and once it gets tall and seeds I come through with a weed eater and cut it down and then let it grow up again.  I have found just by gathering up this material and laying down as stray builds up my yard better over time.  These pictures are an area dug this year and what the grasses did with water collecting in from rains this year on my caliche area.

Also if you want to see more of what I am doing you can go the following link and see other tests i am doing.  I am tempted to go across the draw and see what the guy raising sheep is doing with the manure and see if I can take that for my land.  Just Getting the land covered I notice that by the next year I am able to work it a little more.

https://permies.com/t/71712/Everjams-Farms-Gaines-County-Texas



Goodness gracious!!! That's a nice plan you're going with there.
 
Bryant RedHawk
garden master
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Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
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Any ground cover is going to be great to have in place, it will only help your soil microorganisms thrive and multiply.
There are quite a few that will work in your area, and you might want to think about trying a mix of those that you can locate easily.

Focusing your soil building to a small area is the best way to find what works best for your specific area, think of it as your experimental laboratory, do keep a note book on what you did and how well it worked.
It sounds to me like you have a good plan of attack, let me know how this plan works for you please.

Redhawk
 
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