Technically speaking he is not incorrect--(good double negative on my part). When you apply sulfur to a good "living" soil, the microcritters change the sulfur into sulfuric acid which in turns lowers the ph of the soil. This will also have the effect of dissolving any salts in the soil (sort of like using vinegar to clean your coffee maker). This process takes time however---up to a couple of years to actually have a noticable effect on ph.

When applying sulfur to something like desert soils with very little microcritters, the sulphur will actually combine with the calcium in the soil over time and form calcium sulphate, better know as gypsum. Gypsum incidently is also a salt.

I would add sulfur to any planting beds if I wanted to lower or maintain the ph at a certain level. However, I would not apply it on top of the bed as the guy mentioned, but rather mix it in the soil itself. The sulphur will only have an effect in the vicinity around where it is applied. Obviously, applying on top of the soil will have a minimal effect on the soil acidity near the roots. You can also get an immediate effect of lowering the soil ph by using peat moss when establishing the bed.

Before adding any more to this, what are you going to be planting in the bed? For vegetables, you probably don't need to add too much, if any sulfur. For tropicals or other ornamentals, it is probably a good idea.

Sorry if I was a little fragmented here--I am just trying to give you as much info as I can.

HTH

This is an interesting conversation to me, and I'll tell you why. At one of the recent rose society meetings we had a person speak. They are recommending soil sulpher instead of Gypsum for use in rose beds, and in your lawns. Not because it brings ph down, which would be a good thing for the roses, but because it allows for far better softening of the soil than gypsum. There statement was that newer research is showing that gypsum may be what increases the possiblities of having caliche soil. All the conflicts in information drive me nuts sometimes. Sometimes I think it's better to just take a garden hose and let it soak in the harden area over night really good, and get everything washed down deeper. I wonder if everything we add to our soil other than good ole compost and mulch really is benefical at all. I will say I have used soil sulpher on a particularly bad spot in my yard where it was virtually impossible to get water to soak in, somewhat of a hill area, and now the soil drains much, much better in that area. It did take a couple of years, and several applications, before I saw the end result of application, as you stated.

Easy

Thank you for all your thoughts!
It is a veggie garden (or hopefully will be soon).
I actually had already planned on heading out to get some peat moss today to mix in.

I am so happy I had this forum to bounce the idea off of before making potential mistakes!

DSol, don't believe everything you read!!!!

Just messing with you - everything that comes out of AZRat's mouth is gospel.... heh heh... with a name like that, how could you go wrong?

Hey, was that Elvis?

Hmm, well, I think weve got two processes working here. One is chemical: sulphur. This allows for lowering of the pH in the immediate area, which allows salts (sodium, mainly) to become detached from the soil particles. Add some water, and you have a more "water friendly" and porous soil which absorbs more readily. Plus, the removal of sodium (and other salts, including calcium) allows infiltration of other, more beneficial (from a gardeners point of view) elements/compounds to bind with soil particles.
Gypsum, essentially calcium, plays a similar role, but through a more physical means. It infiltrates the small spaces between clay particles and allows them to disperse more readily. Plus, it can preferentially bond with particles in the soil, thus displacing sodium.
Both processes are good, but take some time. On the order of 3 years is what Ive read. BUT, the chemical process initiated by sulphur can occur more rapidly (albeit in a small area immediately surrounding the sulphur itself, hence the need for multiple applications as our alkaline water counteracts its acidity fairly rapidly), and have a more generalized effect in a given time period. Gypsum, since it has to physically infiltrate the spaces, can take longer and require more manual mixing of the soil. No small feat given our heavy clays. And, if you think about it, we already have plenty of calcium in our soils, but its usually not in a form that can help disperse clay clumps.
Finally, keep in mind that many plants like a slightly acid environment in order to access nutrients.
So, bottom line: you probably want to attack the problem from both a chemical and a physical level. Sulphur can likely yield the quicker results, with less manual labor. But gypsum can also play a role. The addition of compost provides acidity in the form of humic acid (a substitute for sulphur in this case), while introducing a range of material that can mix with, and disperse, clay soils. Simultaneously, it introduces readily available nutrients (read: nitrogen) that allows for more rapid and full growth. This allows root growth to do some of the physical work of breaking down clay-ey soils too. Whew! That was a lot of stuff! By all means, if anyone can explain it better or if Ive gotten something wrong, please tell me!
Not a plug, as Ive not used it yet, but I hear that Disper-Sul, a soil amendment, is what is preferred by some people. Its basically sulphur and gypsum. Seems like killing two birds with one stone to me. Anyone have experience with it?

Let me add a bit more to this conversation. For the most part we are talking about changes in the soil physically as with the case of gypsum and chemically as with the use of elemental sulfur.

Let's clear something up first--use of gypsum will have little if any effect on soil ph. The main benefit from gypsum is improving the soil structure. From an article in Backyard Gardener, Jeff Schalau writes

Gypsum is the common name for calcium sulfate, a very water-soluble form of calcium. This makes it a good source of plant-available calcium and sulfur. In most soils, calcium is primarily responsible for helping to hold clay particles together into clumps, clods, or peds, thus ultimately improving soil structure. In most Arizona soils, the concentration of calcium in the soil is already high, so an application of gypsum will not significantly improve soil structure.

In Arizona, gypsum will only benefit soils when there is excess sodium present. Some water sources have naturally high levels of sodium and, when used for irrigation, sodium can accumulate. This is especially true when sodium containing irrigation water is not applied deeply and losses to evaporation are high. The first signs of this may be a white crust on the soil surface when it is dry, but a white does not necessarily mean that sodium is present.

Over time, excess sodium causes clay in the soil to become dispersed. When clay disperses, the individual clay particles are no longer held together, thus releasing them to move through the soil and concentrate in a single dense layer. Frequently, this layer of dispersed clay is so dense that the movement of water and oxygen is severely limited. Here roots find it difficult to penetrate the layer and water will not percolate into the soil. In situations such as this, applications of gypsum can provide a dramatic improvement in returning the soil to its original condition. The calcium present in gypsum actually displaces the sodium and allows it to be leached deeper into the soil when accompanied by deep irrigation.

.....

Another myth is that gypsum will help reduce soil alkalinity. Sulfur in the form of sulfate will not significantly reduce the pH of the soil. Only elemental sulfur (soil sulfur) or some other acidifying agent will reduce soil alkalinity. Acidification occurs when elemental sulfur and water chemically react to form sulfuric acid. The resulting effect is a slight acidification of the soil near the individual sulfur particles. This is a temporary effect so sulfur can be incorporated on a yearly basis in garden soils, flower beds, and other areas where alkaline soils may impact plant performance.

Full article here

Keep in mind that you need lots of soil microorganisms for this process to work effectively. That is why adding sulfur to bare desert earth with not acidify the soil This is why the addition of organic matter is so important. The organic matter is always in a state of decomposition and supplies materials and conditions for soil born microcritters to thrive. These microcritters break down these materials in a form that your plants can survive. The byproducts like humates and humic acids improve the soil tithe in a similar fashion like gyspum does on sodic clay soils. The process is not permanent. Organic material eventually decomposes away and must always be replenished (hint: add compost every year--twice a year is better)

Note: They do have humates on the market. Most scientists don't even know much about them so for these products, so Caveat Emptor

As for Dispursul, again, the question is whether you need it or not. If you are using raised beds with "imported" dirt and growing something like tomatoes, it probably wouldn't hurt. Gypsum and sulfur bought separately would have the same effect IMO at a considerably less cost though.

DesertSol: Since you are adding peat moss, remember to thoroughly wet the stuff before applying it. I am talking soaking it overnight in a wheelbarrow if that is possible. Peat actually repels water when it either applied dry or is allowed to dry out completely. Here in Arizona, the latter is easy to do.

HTH

i'm over 2.5 feet down and i'm tired of digging. i've reached the hardest caliche. i don't think it really matters at this point. it is what it is! so, what do i do now.

a friend suggested that i place gypsum at the bottom of the hole before i start backfill.

matt at the bamboo ranch said that he plants all his bamboo in 100% composted horse manure. i have access to some +1 yr old manure. that should be composted enough to plant in straight. i want to do this. from what i've read, the gypsum would be good for my situation. however, it might not be necessary since i'm backfilling with organic material.

can someone help me??? i want to plant the bamboo next week.

thanks,

detrick

one more thing.

i dug out over 59 cu. ft. of rock, soil and caliche. i would like to use most of that to create berms. i obviously can't sort out the caliche component, as much of it has crumbled. how would i treat this mix so that i could use it to create berms and build up areas in the yard?

thanks again!

detrick

Welcome to Arizona. Im sorry. Gardening in AZ is a long term project. Caliche is a bummer. Your bamboo probably wont need soil any deeper than what youve dug out already. Id be careful of the horse manure, mix it with other soil, maybe something you purchase from home depot (I like the cactus mix). As far as using it for berms, I wouldnt suggest it. Over time, and not very much time in certain cases, youre just going to be putting the caliche back into your soil. Not good. Dump the caliche (BTW, Im impressed with your persistence), get a friend with a compost pile, start one yourself, and get a home depot credit card.
For the longer term, hire some workers to begin to penetrate the caliche. You dont really have to remove every speck of it, just punch through in as many areas as you can. If you can. Sometimes it (caliche) can be very deep/thick. Since youve removed so much material, you are probably well on your way to creating an area that can be flood watered. The holes punched in the caliche, regular additions of sulphur, compost, flood watering, and time (possibly lots of it) will hopefully cure the problem.
Again, sorry. For what its worth, it might help to know that I now consider picking clods of clay out of my garden to be my meditation time.....

Detrick, from your last post, it looks like you might me over a river bed, hence the nicer dirt underneath. I do think you have dug deep enough---I have dug pretty deep in my yard, but that was to get rid of any %$#%^ bermuda grass that was hiding there.

Now to get to some of your questions

i dug out over 59 cu. ft. of rock, soil and caliche. i would like to use most of that to create berms. i obviously can't sort out the caliche component, as much of it has crumbled. how would i treat this mix so that i could use it to create berms and build up areas in the yard

Is this part of your water retention project or are you going to plant anything on those areas that you build up? For any areas that you are going to plant something on, the only thing I can think of really doing is to get some 1/2" or better chicken wire or similar material from somewhere and it as a using it as a sieve to get rid of some of the caliche and rocks.

For the smaller stuff, I suggest a vinegar bath. Add 1 cup of vinegar per gallon of water and just soak the area. You probably need to do this once a month or so until most of the limestone and caliche is dissolved. You can get gallons of plain white vinegar from Costco or Sam's Club for about $1 a gallon.

a friend suggested that i place gypsum at the bottom of the hole before i start backfill.

I would suggest agricultural sulfur instead of gypsum. You have enough limestone (and therefore calcium) in your soil. I don't know what your soil ph is, but assuming it is about 8 and you want to lower it to 6.5, you need to apply about 4-5 lbs of agriculural sulfur for every 100 square feet and make sure that it is in at least the first 6" of soil. Just mix it in are backfilling. From a ph of 7.5 to 6.5, 2 to 3 lbs for 100 square feet would be the application rate.

matt at the bamboo ranch said that he plants all his bamboo in 100% composted horse manure. i have access to some +1 yr old manure. that should be composted enough to plant in straight. i want to do this. from what i've read, the gypsum would be good for my situation. however, it might not be necessary since i'm backfilling with organic material.

I have no problem with horse manure, compost or any other organic material. However, this is important. DO NOT BACKFILL WITH ANYTHING BUT NATIVE SOIL, unless you are amending an entire area like a bed. If you backfill with manure, compost or any other material, you will run into what is called the daisy pot effect. Basically what happens is that the roots are so happy with their amended soil that they don't venture into the native soil. In time, the roots will actually ball up in similar fashion to what happens in potted plants. You have to ask yourself a question. If the plants won't venture into the native soi, then why are you planting them in the ground?

My suggestion would be to throw a handful of an all purpose fertilzer, or something like kelpmeal, bonemeal or my favorite, worm castings in the hole when you plant, then cover the area in an organic mulch. After it decomposes, eventually, earthworms and other creatures will the nutrients down to the roots. I applied 6-8" of organic mulch in spring each year and by the end of the monsoon season, it was down to 2-3" left. The top foot of soil turned black from its native red and was full of earthworms.

DesertDreamer wrote

For the longer term, hire some workers to begin to penetrate the caliche...... The holes punched in the caliche, regular additions of sulphur, compost, flood watering, and time (possibly lots of it) will hopefully cure the problem.

This is pretty important too. It does seem from your last post that the water drains pretty well. If you seem so inclined (have to be motivated here), dig another hole nearby (not too close) about a foot deep. Fill it up with water and let it drain, then fill it up again. If it drains within 6 hours, your drainage should be fine. Anything longer than 12 hours, I would suggest you have someone come by and punch through the caliche layer at least to allow water to drain properly, or alternatively, plant in higher spots so that the water will naturally drain away. Because you are planting bamboo, my guess it that they won't mind "wet feet" for a small period of time, so this step is optional. However, when you get the inclination to start planting your plumies in the ground, it would probably be a good idea to do it, or go with raised beds, instead.

Good Luck and HTH

I've found the best method for getting rid of caliche is a jack hammer.

Beth, that still doesn't get rid of the caliche, it just allows you to dig through it.

If you want a surefire way to get rid of caliche, dig down to the caliche layer, get yourself some sulphuric acid or another favorite acid (maybe a truckful if you need that much) and dump that acid right on the caliche. 100% guaranteed to get rid of it. The beauty with this is that you don't even have to haul any of the caliche away. It dissolves right in front of your eyes. The downside is that it will cost you an arm and a leg for the acid, and you will need protective gear for the acid and fumes. :-)

Vinegar or pool acid works well in small areas if you are trying to put in a drainage chimney. Again, take proper precautions here also.

OK, I am joking about the first part (it will work though), but I have used vinegar to get rid of caliche in smaller areas. Please don't take the first suggestion seriously.

Now for another way to get rid of bermuda grass permanently, there is always liquid nitrogen............

:-)

Too much sulfur will make your onions HOT! I don't know if gypsum has the same quality, but I sure don't put it in my sweet onion row. So far they have been sweet and big. I do however switch rows every year, and it seems last year's gypsum soil doesn't make this year's onions hot. Good luck with your plantings!

Bizfarmer, you make a good point. The best sweet onions are grown in sulfur poor soils. When you cut open an onion, it is sulfuric acid (emphasis on sulfuric) that make you cry. If the soil doesn't contain sulfur, that acid is no longer made. Gypsum does contain some sulfur (calcium sulfate), so another amendment may be better here. Gypsum contains anywhere from 17%-24% sulfur.