tishtoshnm Zone 6/NMJune 28, 2011

We are preparing planting beds where we are running into caliche. What is the best way to prepare these beds? Will layering mulch and compost help improve the soil structure or is the only viable alternative to dig out the caliche and discard it (which may be difficult without power equipment)? We are hoping to plant roses, perennials and a blue spruce or 2. Thank you for any insight!

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eureka(SS11 LasVegas/Henderson)

This is an important subject to me because I have been trying to garden successfully in red clay in the Victor Valley along the 15 Fwy. You are going to get tons of advice about adding lots amendments and doing lasagna gardening which is fine if you have lots of stuff to shred or have the money to continually buy amendments. I live in the Mojave Desert, I don't have tons of leaves, woody matter to add enough to amend & keep my soil amended. I have short of a 1/4 acre. I have busted my back over the clay and caliche for a number of years and have just come upon a couple of things I'll share that will help you so that you don't run in circles for years. First, buy the book The Hot Garden by Scott Calhoun. He is a landscaper in AZ. He knows the desert soil and knows caliche. Your reference to using a jackhammer is no joke & often used. His book will help you. Also, see if you can find a landscapers supplier that will sell to the public. You want to buy a 50 lb bag +, depending on the size of garden, of Cal CM Plus made by the Art Wilson Co. This is an organic product. This is sold as Soil Buster at Lowe's and Home Depot in rather small bags last I checked. This will break up clay. Plus it unlocks the nutrients that get locked up in clay. You can read about it at If you have caliche, you likely have red clay soil. I just spread the Cal CM plus like a pelleted fertilizer on my backyard. I've done two deep waterings since, my plants are looking a brighter green, I don't expect the soil to loosen significantly until it has gone through several more deep waterings. Ideally, adding this product while creating a garden bed, as your turning over & tilling the soil is ideal.

Caliche sometimes is not very deep, sometimes very deep. It will stop water from draining away. Generally garden books will tell you to dig a "chimney", a tunnel through the caliche to the good soil beneath so the water will drain. The book addresses this well. Personally, I would discard it at the dump unless, your area has some kind of caliche recovery site. Caliche is calcium carbonate and I have not read anywhere how it can be salvaged or why. I can imagine your city may not want it taking space in the landfill so you might check with the city as to how to get rid of it.

I am thinking it likely you are dealing with red clay also; you need to know that clay breaks down amendments super fast and then returns to its natural clay state, that's why using mulch & amendments can become expensive. That is why using the Cal CM plus is what makes all the difference. Also another good solution that makes complete sense is to amend your soil with peat moss. It doesn't breakdown, makes the soil nice & light & once added it drains well. You may hear some tell you that peat moss should not be used due to environmental issues. I haven't done the research but incorporating peat into soil is another form of returning carbon for storage, at least to my way of thinking, to soil which is very organic thinking. Peat after millions of years becomes coal. So I say incorporate peat in the soil so it doesn't turn into coal. Do a search of peat moss on this site if you want to read more on the issue.

Buy the book, use peat moss, add the Cal CM plus for nice soil if you are dealing with red clay. This will give you the fastest results with plants able to do well. Find a good private nursery who have staff that are knowledgable in gardening in your soil. They will save you lots of money, direct you to the proper plants that do well in your area, help you to put the proper amount of water down so you don't drowned everything. You can buy roses that actually bloom through summer. Most roses can't produce flowers during summer heat, they are trying to just survive the heat. There are many roses that can take the heat and flower too. Again your nursery is your best guide. Check with your city or nearest University for additional landscape info.

I hope this all helps. Even if you have a small garden, this is an excellent solution. Of course if you have clippings & leaves, start a compost pile as that will enhance your soil also. I just fed mine canaloupe skins, a couple soft, chopped up apples, banana skins, & egg shells. I also spray fish emulsion once a month to keep the soil bacteria & earth worms happy & healthy, as well as throwing down composted manure twice a year. Your soil bacteria and earth worms are very important to the success of any garden.

    Bookmark   June 29, 2011 at 3:08AM
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What your soil does need is organic matter and you may well need to rely on peat moss if nothing else is available, lots of it. Soil bacteria and earthworms need organic matter to live on, and you will need to continue adding tht organic matter every year because they digest it and convert it into plant food. Clay soils do not eat up organic matter any more then my sand does, but if I do not continually add organic matter to my sand it will not hold moisture or nutrients.

    Bookmark   June 29, 2011 at 12:13PM
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Ignore kimmsr ... he's from Michigan and has no clue what caliche is and how bad peat moss is to deal with in a dry climate.

How thick is the layer of caliche and how far down is it?

If you can break through it in a few spots you will get good enough drainage. There are several ways to open up drainage in a caliche deposit.

If it's not too thick, whack it with a sledgehammer, pick, or a crowbar. You can even use a 3-lb sledge and a "rock drill" to hammer some holes into it.

If it's more than a few inches thick, you have to get creative. And you have to get a gallon or more of pool acid. Hammer out a basin or small hole and fill it with acid. Let it foam and bubble and eat away the caliche. When it stops bubbling, the acid is used up. Carefully dilute it with some water and hammer out the softened caliche. Keep doing this until you have a hole through it.

Once you have a few holes in the layer, deep-rooted plants can be planted. Their roots will open the cracks even wider. Squash, for example, has roots that will go down 6-8 feet if you water that deeply.

The usual thick mulching and composting and keeping the soil moist will help. When you water, water deeply enough so the water goes through the holes and into the dirt under the caliche - that attracts the roots and they break up the caliche a bit more.

Be careful to avoid over-improving the soil over the caliche or you get the dreaded "flower pot" effect and your trees will not spread roots widely enough.

NOTE: Unless you see blue spruce thriving in your area, try an Atlas Cedar, the blue variety. They deal with alkaline soils and summer heat better than blue spruce.

    Bookmark   June 29, 2011 at 2:35PM
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albert_135(Sunset 2 or 3)

Ditto: lazygardens ... Ignore kimmsr ... he's from Michigan and has no clue what caliche is ...

I once lived in a place where the caliche was only about three inches thick. This "flower pot" effect mentioned above is quite real. I had a drill, about 2 inches in diameter. I could drill holes in the caliche and plant poplar trees above the holes and they would send roots through the holes and break it up - somewhat. You might try this and see what your perennials and spruce would do. I am not recommending this unless you are predisposed to be fascinated with experiments.

    Bookmark   June 29, 2011 at 3:42PM
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eureka(SS11 LasVegas/Henderson)

Geez poor Kimmsr, and such a knowledgable guy too. Although I gotta differ with you Kimmsr on organic material added to clay soil breaking down super fast. I don't know exactly why any organic amendments breakdown so quickly but it sure does as if I had never added it just a couple months before. Never saw that when I lived in Orange Co.,CA or when living in San Francisco. Maybe it has something to do with red clay but it is clearly noted in several of my books on desert gardening and I've seen it mentioned in various univ. papers. It happens year round, doesn't seem to matter what the temp is. If I add Kellogs amendment for clay soil which has some sizeable woody chips to a planting hole, 2 mo's later, there is no sign of any amendment. The soil will be a bit looser but that will return to hard clay not long after. Here in the Mojave Desert, I struggle to find enough stuff to shred, compost, and add to the soil. Cannot afford to buy enough amendments, city gives very little away cuz they need it and use it up fast. And we have two huge commercial composting facilities that gobble everything from the US Forests in the area, sardine die offs in beach cities, anything they can get their hands on. The wind blows leaves away, don't know where they end up but not many on the ground. Red clay soil has a voracious appetite.

    Bookmark   June 30, 2011 at 3:12AM
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While my experience with caliche soils is limited, I only gardened where they existed one year, anyone that thinks that just because I live in Michigan and therefore have no knowledge of them is wrong. Caliche soils are formed where CACO3 is not washed out of the soil due to the little rainfall available to wash it out. The year I did garden in caliche soil we did add lots of organic matter, or it had been added in previous years, and even with low rainfall and not much available irrigation water we grew lots of food.

    Bookmark   June 30, 2011 at 7:00AM
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tishtoshnm Zone 6/NM

Thank you for the responses, this site is awesome. Pool acid sounds like it could be fun. Before I start with that though I'll have hubby evaluate whether or not that would contaminate the groundwater.

My clay is not red clay, which sounds like it could be a blessing. When our house was built on a sloping lot, instead of building up the site, they cut into it which seems to be the reason why we are hitting the caliche in this area and not others. DH thinks that the caliche layer is in the process of forming (he has a much stronger geological foundation than I) and we are finding quite a few limestone rocks as we are digging. My biggest fear is the flower pot effect so we will be watching the water carefully. I have also considered planting alfalfa in the area to begin breaking up the soil even more. As I am on a 5 acre lot, I find places to discard the caliche pretty easily, although it is a bit of a walk.

BTW, Kimmsr, I do like peat moss and add it quite liberally in my vegetable beds and with my roses, but never, ever allow it on the surface.

An Atlas Cedar is too big for the spot I want it for so I may have to research more thoroughly. I am in the mountaints so my summer is not nearly as intense as it is in other areas of NM and I have seen many a blue spruce growing here so I may take a chance. Although, I bet I could get the Atlas Cedar in another area, what a gorgeous tree.

If there are any more ideas, please keep them coming. I appreciate them all.

    Bookmark   June 30, 2011 at 12:44PM
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tishtoshnm Zone 6/NM

And Albert, I love experiments and so have no problem experimenting with say roses that are roughly $20 a pop. I am not inclined to experiment with the tree though at whatever a decent specimen is going to cost me but I will need to figure some of that out soon because we were hoping to use the tree as part of a windbreak.

    Bookmark   June 30, 2011 at 12:50PM
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eureka(SS11 LasVegas/Henderson)

Tishtosh: I have a lovely Raywood Ash in my yard. This tree turns dark purple w/cold temps & has narrow, long, green leaves. They grow well in this desert environment, also Modesto Ash. It was quick to grow to twenty feet and still growing. It is 20 ft wide. Branches tend to grow up and out. Modesto Ash grows wider and the leaves are bigger. They are recommended for this area. They do not seem to have issues growing in clay soil so anything better but with low rainfall will likely do fine.

I thought I heard it all when it came to clay/caliche but acid is a whole new one. Yikes.

    Bookmark   July 1, 2011 at 2:46AM
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dchall_san_antonio(8 San Antonio)

When I think of caliche I think of a rock that can be sawn into bricks and used to make buildings. I believe it is the same rock which is called caprock in parts of Texas and New Mexico. Here is a picture...

The type of rock called caprock has different connotation in other parts of the country and the world. Texas caprock can be several feet thick. As a garden growing medium, it is best to call it a crushed rock rather than a soil.

    Bookmark   July 3, 2011 at 2:35AM
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The caliche that really matters to gardeners is the stuff that forms as a subsoil layer.

Here is a link that might be useful: Wikipedia on

    Bookmark   July 3, 2011 at 1:18PM
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Hello folks. I've been doing a little research into caliche, and I'd like to share the following results of that research with you. Rather caliche is a problem or not depends on the surface soil depth before you get to caliche, what kind of root system your plant has, and what you want. So, you need to know all three before deciding what to do.

For instance, caliche is hard for roots to penetrate and will more or less force plants including trees to send roots horizontally on top of the caliche layer through the surface soil if you have any mentionable surface soil. This is one reason some ranchers and farmers hate mesquite trees, but it's partly because the mesquites can't get through the caliche so it spreads out through the surface soil competing with other plants for water and nutrients. If the mesquite trees were able to get through the caliche and grow deeper it wouldn't be such a problem. Make sense? So, consider the surface soil depth, the plants root system, and what you want the plants root system to do.

As some of the other posters here have mentioned finding out what kind of soil you have will help your overall plan of attack. The good news is that in many cases someone has already done the work for you like the United States Department of Agriculture. Below is a link to where you can find published soil surveys for your state and county.

The soil surveys do take a little navigating. Pick your state, pick your county, wait for pdf to load. In the pdf should be a "index to map sheets" section where you can locate your exact location visually. There isn't a lot of additional information on these maps except the soil survey data so you may need to compare the soil survey map with another map in order to find your exact location. I was able to find my exact location by comparing a "mapquest" generated map (use the satellite view) of my location to the soil survey maps. Take your time comparing the maps and make sure you have the right location. Once you see the USDA soil survey map I think you'll understand.

Soil survey and classification maps are not neat and orderly in the way you may be used to and rely on land features to determine boundaries and soil types rather than roads, property lines, etc. For instance, if you live on a hill, but you also have property that is in a valley the USDA folks will use the hill you live on as a boundary and having one type of soil and the valley as another boundary and having another type of soil. Again, take your time and make sure you have the right location.

Once you've found your location there will be a number or something similar indicating the soil classification for your location. Then you want to find the "detailed soil map units" or "detailed soil description," and look for your number. Now, you have to do a little interpreting because the USDA folks don't use caliche as a term so much as they describe the layers. Read the description and plug in your knowledge of working with the soil in the area. The descriptions often use very technical wording so look up any words your not certain of and it'll make better sense.

Caliche can be amended by mixing it up with other stuff to make the dirt better so you don't have to get rid of it. Caliche is alkaline, partly composed of calcium carbonate, and holds water really well when absorbed. Vinegar can be used as a fertilizer (diluted), it dissolves calcium carbonate, and increases acidity (decreasing alkalinity). So, break up the caliche into smaller chunks, mix it with some other material like sand to help improve drainage and maybe some other material that's a little more nutrient rich, water the mix down with a vinegar fertilizer, and you'll have a fairly decent soil. Of course do a little experimenting and check the ph with a home test kit and make any other corrections as needed.

    Bookmark   August 4, 2011 at 4:45PM
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Screw your sand and vinegar Brandon

    Bookmark   August 6, 2011 at 2:14AM
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Two fundamental errors- the sand, the vinegar. If you don't know why, you shouldn't post about it.

    Bookmark   August 6, 2011 at 3:00AM
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Pool acid sounds like it could be fun. Before I start with that though I'll have hubby evaluate whether or not that would contaminate the groundwater.

It won't, because the acid reacted with the caliche and neutralized itself.

    Bookmark   August 6, 2011 at 1:39PM
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"Two fundamental errors- the sand, the vinegar. If you don't know why, you shouldn't post about it." - mackel in dfw

Firstly, here's a link on a vinegar fertilizer solution, why it works, how often to apply it, and how to dilute it.

Secondly, I'm guessing you ran across some articles on vinegar and sand reacting or perhaps you have something else in mind. In any case, all of it is fairly negligible considering how much the vinegar is diluted and how often your supposed to use it.

Caliche = little to no drainage.
Sand = plenty of drainage.
Caliche = hard calcium carbonate.
Vinegar = break down of calcium carbonate = looser soil.
Caliche = alkaline = needs an acid source to balance ph.
Vinegar = acidic = ph balancing agent for alkaline soil.

Using a vinegar solution as described in the link above is a long term slow amendment of caliche at best due to the vinegar being diluted so much and soil ph should be checked on occasion to ensure your not overdoing it, but it will aid in making caliche more favorable for planting in over time.

I use a 50/50 mix of sand from a wash nearby and whatever came out the hole I dug, mostly caliche the majority of the time, for planting native vegetation I use for landscaping in out here in the Sonora Desert. I also use the vinegar fertilizer solution as described in the link above with no ill effects. The neat thing is people can try it for themselves and see how well it works. If your skeptical try it with just one plant.

    Bookmark   August 7, 2011 at 8:45AM
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Aaargh! Please stop! I lived with caliche in Texas for 20 years. It had no bottom that I could find. If I had to do it again, I'd build raised beds for drainage and fill them with garden soil and compost.

Peat moss is fully decomposed and provides NO fertilizer. It only dries up and washes away. Instead, use mature COMPOST (plant or animal manure) to hold soil moisture as well as fertilize. Now that I live in the land of "peat harvesting", I try never to use the stuff! Totally NOT sustainable, and useful only for seed starter in POTS.

    Bookmark   August 7, 2011 at 9:52AM
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dchall_san_antonio(8 San Antonio)

I just mentioned this in another reply. There is not enough vinegar or pool acid in the world to dissolve all the caliche. If you don't dissolve it all, then you still have it and still have the problems.

As Brandon says, try it.

    Bookmark   August 11, 2011 at 11:21PM
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Vinegar is also used as an herbicde... it kills plants. Stick with organic amendments that add to the soil composition rather than change it. Trying to change the chemistry of soil is a lot like trying to turn metal into gold... beware of the results.

    Bookmark   August 12, 2011 at 9:25AM
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dchall_san_antonio(8 San Antonio)

zuni, I don't want to take away from your second and third points, but vinegar is only a herbicide when sprayed on the leaves of the plant. As soon as vinegar hits the soil it neutralizes and becomes another carbohydrate used by soil microbes as food.

    Bookmark   August 14, 2011 at 10:34PM
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If what dc_hall says is correct, then pouring vinegar on caliche should have no effect whatsoever. If it happens to not be true, the plants will die. In any case, using vinegar on soil is a bad idea.

    Bookmark   August 16, 2011 at 4:00PM
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toxcrusadr Clay Soil(Zone 6a - MO)

Vinegar sprayed directly at full strength on leaves will kill plants. Diluted in water and poured into alkaline soil, not so much.

I am wondering why vinegar is perceived to be such a problem for the plants but not pool acid? Which I assume is concentrated hydrochloric, about 10,000 times stronger than vinegar. Not that I'm against it, I've never worked caliche. I tend to agree that it's going to be hard to change a leopard's spots though.

kimmsr's perennial advice to Add Organic Matter is always a good idea, it just isn't the solution to everything. Sand, too, can make concrete if you're not careful.

I'd be tempted to import something more like usable soil and make raised beds. I wish I'd done that 20 yrs ago for my garden. But that may not be practical for you.

    Bookmark   August 17, 2011 at 12:51PM
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zuni & mackel vinegar works & does Not kill my plants.
I have red & white clay in town, but not on the sandy farm 14 miles away.
Have you tried it.
I also added sand to my clay & have great drainage, even with 1/3 of the person on this site telling me It Will Not work.
It did work!
Some of us need to stop surfing the net, long enough to try what we read, to see if THEY know what they are saying, is fact.
I do not care if they are high school drop outs or PHD, one must try it to Know if it works.

    Bookmark   August 25, 2011 at 9:59PM
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toxcrusadr Clay Soil(Zone 6a - MO)

You are right about that. Sand in particular will work, one just needs to be careful how much is added. A small amount will have little effect. There is a range in the middle where (depending on the type of clay, probably) it can form a concrete-like mixture. Past that (usually 1/3 to 1/2 sand is recommended), there is enough sand to prevent the clay particles from 'concreting' together. But yes, one has to try it, it just helps to have some knowledge of the issues in hand.

    Bookmark   August 26, 2011 at 11:45AM
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toxcrusadr Clay Soil(Zone 6a - MO)

And, I've had pretty good luck adding a sand-silt mixture to clay regardless of the amount. Having the entire range of particle sizes gives you a nice loam.

    Bookmark   August 26, 2011 at 4:05PM
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jolj, In the interest of sustainability, I would not use unsubstantiated home remedies to "correct" the soil, such as pool acid or quantities of vinegar. They may be effective in breaking up caliche, but that is not enough to recommend their use. In most locations, dumping chemicals of any type on the soil violates environmental laws... with good reason.

    Bookmark   September 19, 2011 at 12:47PM
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tishtoshnm Zone 6/NM

Zuni, DH ran the chemical equation for using pool acid to react with the caliche and the byproduct of the reaction would be water. We are very cautious about interacting with our environment as this is the place we decided to make our home and hope to leave to the kids, someday. DH is also a water resource specialist for the stat and is very knowledgeable regarding the aquifer from which we get our water and we are very aware of the need to keep it as clean as possible.

    Bookmark   September 19, 2011 at 1:25PM
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curtludwig(New England)

DH is a smart man, zuni apparently failed highschool chemistry...

    Bookmark   September 20, 2011 at 1:12PM
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