Clay soil is generally very high and nutrients and with the addition of copious amounts of organic matter can be a an excellent growing medium.

There are different types of clay--I know around the TX/LA coast you can get something nasty refered to as gumbo clay, but the clay around here once it is fluffed up with organic matter (something my horses provide in abundance!) so that water can move through it more easily can be wonderful. I just need to be careful about re-compacting it.

I would never assume that simply because it is "clay" it should be replaced!

You might try adding some garden gypsum with the organic matter. Truthfully, it depends on what is easiest for you. At my last house, the clay was so dense it was good only for making bricks so I dug it out (with an axe). It was less work overall than trying to amend it. Breaking up all those clumps was exhausting so I tossed it all in a wheel barrow and dumped it in low spots in the yard.

Evenie

Generally it's good to work with the soil you have, and clay is fine as long as you avoid treading on it or working it when it is too wet. Give it an inch of water and let it dry just to the point that clods will break up rather than dent or squash when struck with the shovel blade. Use a mattock to turn up the clods and let the weight of the tool do the work--whacking on hard soil will give you tennis elbow. You only need work the soil 12" deep. Unless your soil has been very badly compacted, working it won't be impossible if the moisture level is correct.

Probably you don't need to worry about drainage unless there is a layer of salty hardpan down there. These have to be broken up with a pick and removed. Normally there are cracks in clay subsoil that allow some drainage. In the desert, the only reason you need drainage is to allow for flushing the soil with extra irrigation a couple of times a year.

Don't add sand to clay soil. Add organic matter. As Evenie suggests, gypsum helps salty western soils, say 3 cups per square yard. You will also need about 12 oz of sulfur per square yard to adjust the pH. and you could add 1/3 cup of triple super phosphate. (All of this dug in.) There is no need to worry about low potassium as this is supplied by a normal fertilizing program and it moves down through the soil.

When you have moistened the clay soil so that it is easy to dig in (but not WET or you'll be digging sticky gluey gunk), dig that foot deep hole (maybe even a bit deeper if you can) where you will want to plant a rose. Then fill up the hole with the loose clay dirt and water well (as in nearly fill it up with water)--and see how long it takes to drain--10-20-30 minutes? Good drainage. Not drained an hour later? You may have problems.

A couple shovel fulls of manure/humus mixed in with the clay soil in the hole is definitely a good idea. For ph, follow Michael's directions.

I only find clay to be a problem when it is gooey wet or when it is all dried out and therefore nearly brick-solid--but in most gardens, the ground would get watered more than that.

Kate

My house was built on former cotton fields (I think it was cotton that was grown), but that was 40 years ago, so the soil when I moved in was not too bad, at least compared to the newer houses built in the desert areas, more on the edge of town. So, when I moved in the soil was clay, but somewhat tillable. Since I moved in (which was 13 yrs ago, geez, that long), I have consistently attempted to enrich the soil with compost, kitchen vegetable scraps, alfalfa pellets, etc. So, the soil in my beds is pretty friable.

So, in my experience, the clay soil is ok, but needs to be generously amended with organic matter, as others mentioned.

Personally, the only way I would remove and replace soil is if it was actually construction debris and not something that could be worked on to improve.

What we did to create our veggie beds was to wait til the winter when the ground had gotten enough rain to make it so I could get a shovel in to it. I would dig a shovel height out and flip that dirt out on one side of a trench I was creating, then I would dig another shovel height and flip that dirt to the to the other side of the trench. We added compost and leaves collected in the fall to those piles of dirt, breaking up cods with a hammer and mixing it up well and then shoveled that back in to the trench. Then we would dig a new trench next to the first until we had areas that were about 20x8 that had been dug up and amended. We were very careful to avoid walking where we dug and staying out if we had gotten any rain because we did not want to recompact the soil. We got more veggies out of that soil than we can use and it is soft and easy to work with even when dry at the end of the summer season.

We keep adding more compost and watch where we walk

I should have said--gypsum is good provided your soil test showed high sodium, not high calcium. If there are white sheets or lumps in the soil, these are probably limey and indicative of excessive calcium. Gypsum would add more calcium. A bloom of white crystals at the soil surface after rain or watering could be gypsum.

Hi,

The area in my front yard is clay that drains properly. The area in question is on the side of the house in the backyard, and when an 18" x 18" square hole is filled with water, it has moved down about 5-6" about 6 hours later. This is giving me the most cause for concern, especially since as I continue to dig deeper and deeper, I do not seem to dig up anything but more clay soil.

Michaelg, my soil usually ends up retaining too much salt and consistent with your recommendations, the soil testing company suggested that gypsum be added. The suggest a rate of 13C per hundred square feet. The level of calcium was in the high range and the magnesium was at an even higher level.

Kippy-the-Hippy, boy have I been trying to work with that soil. I have been planting veggie scraps about 12" down in between the plantings hoping to add organic matter to an area that tested low within the low range for soil.

Thank you all for the advice regarding the moisture that is most ideal when digging. I probably have given myself tennis elbow, plus more back and neck problems. We are now paying my teenage stepson $10 per hole; it will be money well spent.

Lynn,

Rather than bury veggie scraps, if I was you, I would purchase some compost and mix with the clay. You can sit next to your pile with some gloves and do it at an easy pace. I find that things buried under layers take a long time to break down. On the other hand the compost seems to vanish in to crumbly soil

Hi Kippy,

I usually mix a generous amount of compost in my planting holes, along with soil sulfur and most recently gypsum. So am I correct in surmising that compost would be better for my soil than the veggie scraps?

I am so new to composting; I just began a couple of months ago after asking questions on the soil forum, figured I would just jump in with those scraps ( cucumber peels, lettuce, carrots, bell pepper minus the seed, banana peels are primarily what is buried), as it did not seem that it would cause harm but be beneficial. Given the poor organic matter in my soil, whatever will yield the best results compost vs. what's created by my scraps, is my goal.

This post was edited by desertgarden561 on Sat, Oct 12, 13 at 20:10

When you are amending the soil with compost, it is a not good idea to dig holes and just amend them. It is better to dig the whole area and amend it entirely all at once. If you just dig holes you can create drainage sinks that will pull all the water and your roses can drown from too much water.

If you do decide to dig holes (and I can't blame you; it sounds like quite a job), then put the compost in a thick layer on the top of the ground and allow the worms to work it into the soil over time. It will take a year or two. Renew the compost when it gets too thin. This should be an ongoing process. And be sure to pull the compost away from the canes of the rose canes by several inches. The compost should not actually touch the plants.

We've given you lots of choices, haven't we! Best of luck with your project.

Rosefolly

You are being very smart and thorough in appriaching with what seems to be a problem soil.

The rate of drainage you report from your percolation test (1 inch/hour) would be barely adequate if the subsoil was already saturated when you started the test. If the subsoil was dry when you started the test, then I think you are right to be concerned about drainage.

By amending the soil, you are creating a better environment for rooting, but I doubt you are improving drainage much. Water would still need to escape through the unamended deeper and surrounding clay, which apparently is compacted.

If it is possible to raise the bed even six inches, that would provide a zone for the feeder roots that is capable of being flushed. Feeder roots are concentrated in the upper soil where there is oxygen. If raising the bed is not feasible, the roses may be OK anyway. At least you don't have to worry about heavy persistent rain rotting the roots.

About organic amendments: compost provides a temporary fluffing, but bacteria will eat up all the visible particles in short order. What causes long-term improvement is humic acids, a black syrupy material that remains behind in small amounts. This glues the clay particles together into crumbs and darkens the soil.
By volume, manure is a much richer source than compost, and compost a much richer source than raw vegetable matter. It's all good, but manure is the best stuff for digging in to change soil texture permanently. Continuing to mulch with any OM will continue to add humic acids to the top zone. In the West, it might be well to use weathered (rained-on) manure, which would be lower in salt content.

Rosefolly,

Good.... whew!!! You confirmed that I have been doing the correct thing here. I have been gardening for over a decade, but definitely lack experience in various areas. I finally received my Vintage Catalog and have been drooling... but learning about the O.G.R.'s too. I am so enamored with the teas, noisettes, bourbons and gallicas. I have thought of joining a rose society again.

My current issue was a non-issue with two previous homes because I was the first owner on virgin land, and saw to it that the planting areas were amended first. When I gardened in California, the soil was great and properly amended by the previous home owners. I just had to learn what to grow and where; one year I planted sun loving annuals in partial to full shade.... silly... silly... silly

I always lay down fresh compost twice annually. During the spring and then again in August. My husband had suggested to amend the holes for new plantings and then just amend or put my gardening scraps in the space between the existing plantings and new ones. I do believe what exists was planted properly with soil amendments; maybe these areas have caused issues for the rest of the soil in the area that is largely not amended???

Michaelg... weathered rain on manure:( we are having record rain this year as we hit 4" during our monsoon season that ended in September, and we get the greatest amount of our rain during February.

Would steer manure be good, as that is all I can find at the big box and sometimes at local nurseries? There are horse stables in the vicinity, but based upon what I have read, I would not trust it, and definitely cannot identify what should or should not be used. I added steer manure to the bottom of some of my planting holes; the roses described as "heavy feeders or requiring good soil.

Lynn

Hi Lynn

You have gotten some great advice.

Personally, I would be a bit careful of the HD type bagged steer manure even though it is cheap and easy to find. If you have a good local nursery that has a better quality of manure, you might like that better. I have purchased a couple of bags of the HD type, but it is full of plastic, tarp bits..etc pretty much anything you might find at the stockyards. Not sure they feed/treat the feed lot cattle anything better than you might find at a quality stable where the horse owners want to keep them in good shape.

One thing about our method of creating the garden beds, breaking up the soil, adding organics and putting in back in the same "hole" made it in to a raised bed. We are on a hillside, so we used that to create terraces. We still add more compost and mulch.

As a local organic gardener says in his classes: Compost is when you can not tell what it is any more and it looks more like soil than what it once was. Mulch is identifiable, you can tell it is leaves or veggie scraps etc.

Bagged steer manure is produced mostly at midwestern feedlots where it is composted out in the open in big piles worked with heavy machinery. Because it has been leached by rain, it is low in nutrients compared to stable manure, but also lower in salt content. I understand Kippy's preference, but for the purpose of altering soil texture, Black Kow would be fine. I have used it, a 2" or 3" layer mixed into 10" or 12" of soil depth.

Michaelg,

Thank you :) for the steer information and reference.

Michael G., Kippy., RoseF.., DublinB., Jasper, Thank you all for your input. I am breathing a sigh of relief and feeling enlightened.

Lynn

Drainage worries in Las Vegas? The Las Vegas with 4.2" of annual rainfall?

hoovb,

Timer driven drip line irrigation; homes are built with it included in the yard or you install it pronto. We deep water daily during the heat of summer, and actually year round, but then at different frequencies. If not, a lot of what we grow would become an annual. Many people have removed their lawn, and it is illegal to have front lawn in areas with homes built after about a decade ago. The system is if much more efficient, and not having a lawn reduces a lot of the water used.

All of the soil in my backyard except for the raised planter is clay.

This post was edited by desertgarden561 on Wed, Oct 16, 13 at 16:55

The only reason drainage is needed is to be able to flush the desert soil occasionally with excess water in order to keep the salts from building up to the point that roses have trouble taking up water. I have no idea whether that would be a problem in Lynn's yard, but a complete soil test will include a measurement of total salts. Fertilizers, and also the water from Western reservoirs, contribute to salt buildup. If at some later point the roses mysteriously stop growing well, that would be a possible cause to check out.

Sorry to be a bit pessimistic but saline or even worse sodic soil with pH of 8.6, low in nutrients and organic material is not what I would attempt to garden on. Very difficult to ammend, it will always be problematic for you. Yes you can use gypsum for unbinding the sodium ions if the soil is sodic but then you have to use lots of water to leach it out. If your water is scarce and alkaline and your soil is clay this may create more problems than it will solve. Acidifying irrigation water on a consistent basis is problematic for the average gardener. Yes you can add lots of organic materials but it will take a lot and depending on the material, your salinity and related pH problem will still be there. Yes you can use acidifying fertilizers like ammonium sulphate and urea to help with your pH but it can take years for that to have any real effect and you may make worse your salinity problem in the process. It can take many years of copiously amending the soil to have a reasonable substrata to work with.

I would opt for soil replacement if that will be at all possible. Failing that I would opt to plant plants tolerant of these conditions and do some of the basic organic material amending described above. Roses, in general, are not tolerant of such conditions.
Nik

This post was edited by nikthegreek on Fri, Feb 21, 14 at 9:29