Althea, before jumping to conclusions about one particular amendment to your Minnesota soil, might I suggest you ask the people who are well aware of what constitutes your State's soil quality.

Just put into your browser: "Soil of Minnesota"...
and follow the yellow brick road.

I remember reading a while back; a lady asked why her particular tree was not doing all that well in her Minneapolis backyard.
The responder told her to dig up her tree and take it 200 miles east and it will grow beautifully. Such limited distance can make such a difference in your state's quantity of quality says a lot about it.
I forget just what tree it was....it was a common variety as I recall....not something out of any ordinary homesite.

Before jumping into making such a possible big change, it would prove your benefit to ask quetions first.....shoot later.

Hi Jeanne. It's fill, almost pure sand deeper than 8-10 inches, not really "native soil".

I have gardened many years with a sand clay mix without the use of compost or humas. It is one of the best mediums for garden use.

But the first thing you should do is find out how much silt there is with your sand. Do the jar test. If the test shows more than 30% non-sand, do not use clay as an amendment. Follow the advice on this forum using organics for amendment.

On the other hand, if the soil test indicates an almost pure sand, you can use clay. But don't use the porcelain clay, it's likely a form of kaolin, based on aluminum, bad for plants. Potters clay or ball clay might be OK. Do not use more than 1 part clay to 20 parts soil.

althea,

You are getting very good suggestions tonight IMO. Rodale is using clay subsoil to make their compost, they dug it out the ground. Ground clay is packed with nutrients, they are using it to coat the organic matter as it composts. The idea is to not spend any money, find what is around you to use if you can.

I can not speak on sandy soil, for I do not grow in sand, thus my agreement to seek answers close to home. You can make great compost without clay, you can use soil, you can use nothing but greens and browns. Composting is like using an adjustable wrench, it will open up to fit any size within limits.

Some with sand use the lasagna bed method, that may be an option to look into. The important thing I believe is have fun and don't stop learning...

Blutranes

A nursery I worked with in Ga had plenty of clay but not in the pots he was growing in. We set up a mixer with clay added then sprayed the pots with this water with clay suspended in the water. This improved his growing greatly with relatively small amounts of clay. You may find that you don't need so much clay as you need to hold it in the sandy soil. This can be done by putting the clay on the surface of mulch and let it be moved down by the normal process with the organic matter binding it with sand, silt, organic matter, etc.

I found this on a University of Minn site, this statement; "organic matter is absolutely necessary with sandy soil".
Now if you dig it in you will damage the structure of the sandy soil causing it to leach out more readily.

Good point about porcelain's high aluminum content pls8xx. That would have been my last choice because of the higher cost. Earthenware, my first choice is the least expensive and I don't think the iron would cause any problems. Also thanks for the ratio recomendation.

Blutranes, potters clay is mined just like the Rodale clay. The high nutrient content is another bonus.

Maggiemae, your nursery experiment is interesting. I had thought of just adding some to the surface along with compost topdressing and letting it settle as you suggest. This would be a good method in areas planted with perennials.

Looking at the properties of the three primary potters' clays, I came across this reference to paper clay, which is just adding newspaper pulp to clay. This seems like a promising idea for amending the veggie garden - mix a paperclay slurry in to the sand. Any thoughts on this? (It could also be good way to me to use up my porcelain by making it into paperclay for sculpture. :~) )

Here is a link that might be useful: paperclay

This is a link to the article Blutranes posted.

Here is a link that might be useful: rodale

althea,

I would experiment and find out for myself how it does, that way you know for sure. No soil is bad if you are willing to work with it given enough time and room. The Rodale Institute is experimenting with a process that has been documented successful for 80+ years. What you described is clay with some "brown" mixed in IMO, all you need now is the right amount of "green". This is my thinking, but then I love to test stuff...

Blutranes

That was an interesting article from Rodale. Many years ago I had a compost pile of shreaded oak leaves. After the first week there was little sign that the pile would heat up. But I did notice that there were hot spots about the size of a baseball. At the center of each of these hot spots was a small lump of clay.

The Rodale study does not surprise me. The early high heat should be expected. The ability of clay to absorb and hold plant nutrients is ledgendary.

But for most gardeners, adding clay to compost piles is a bad idea. Once the compost is applied to a soil, it begins to break down. In warm climates this happens quickly. Once the compost is gone, all that is left is the clay. Repeated applications of compost containing the clay amounts from the Rodale study will result in significant build up of clay in the soil, leading to trouble in silt based top soils.

Top soil is good, clay is great, but don't ever mix the two together.

I hate to be a spoiled sport, but if I had a sandy soil I would not add any clay.

Sands have the disadvantage of not supplying water well, they do not maintain organic matter, and are loved by plant parasitic nematodes. But on the plus side they warm quickly, can be worked right after a rain, and tend not to compact.

The only reason I can think of for adding clay is to improve the water supplying capacity. In that regard clay wonÂt help much. Clay holds water, but it does not like to give it up. It may help slightly by creating some structure, but I would rather just irrigate more often than deal with the challenges associated with clay.

If you want to amend your soil I would suggest silt or compost. If you have your heart set on adding clay I would advise you to add a small fraction of what you think you need because a little goes a long way.

Clay also is important because it holds nutrients, as far as I know

fertilizersalesman, you make me smile sometimes, no, a lot. We are speaking of adding clay to the compost pile, not the soil. But you did say you don't click on links; again an understatement...

Blue,

I swear I read every one of these posts. I made the assumption that the clay in the compost would eventually end up in the soil.

Hooray,

Good point, the clay would increase the CEC of the sand, but so will the compost.

Yes, but the clay in the compost will give it more CEC due to the microbes and the organic matter that composted. A clay compost blend will add with the sand better than just adding raw clay; we know what happens when one tries that. Seems they are attempting to create a artificial humus (CEC 500) by using clay (CEC 40). I am surprised you didnÂt mention Rodale is using Leonardite ($159.85+shipping and handling) on their pile. One would think they should have had some humus laying around somewhereÂ

Blutranes

OK, I admit I did not read the link. However I will make a few comments. Clays are not all created equal. As a general rule the higher the CEC of a clay the stickier it is and the more it shrinks and swells. Although sands have a low CEC that is not neccesarily a big deal. I would not add clay just to raise the CEC.

There are no 'bad' soils, they just have different properties. Learn to work with what you have, with a sand you have to water and fertilizer with lower rates more frequently. If you can do that sandy soils are very forgiving and easy to work with.

Pls8xx, I was thinking we could just shovel the topsoil off to the side and work some clay slurry into the level below. What happens when one mixes topsoil with clay?

Fertilizersalesman, increasing the waterholding capacity is the primary reason for this experiment. (Blutranes, I love to experiment as well.) We're new to this gardening space - 2 years. These first two years I went the compost and organic matter route which helped a lot. Last year we had a drought with an extended stretch of 90+ degree temps. I would rather not garden than have to water almost every day. This fall Altheo dug the biggest and deepest hole yet revealing the seriousness of the problem. The pure sand beneath the topsoil was bone dry. On the good side, we don't have any problems with a wet basement. :~)

"Clays are not all created equal. As a general rule the higher the CEC of a clay the stickier it is and the more it shrinks and swells."

This is exactly what I'm hoping to learn about the primary clays used for pottery. The choice is between earthenware and stoneware. I'm leaning toward earthenware. Unfortunately, the searches I've done deal primarily with properties of the clays for making art, not as compost or soil additives.

damn fertilizersalesman, I thought you had changed your evil wicked ways (Smeagol swore!...Smeagol lied). And you still have the nerves to want to comment? I told you, you make me laugh when I really can't afford to breath real hard. At least you are honest about it.

Ok, your point about "bad soil" is valid over here, but you knew that. Sand evolves to silt evolves to clay, nothing wrong with starting at the beginning. A raised bed comes to mind; that will work on cement if thick enough. Again it boils down to the gardener and what he/she is prepared to do...

Blutranes

OK, I hate to always be on the other side of the fence BUT adding clay will increase the soils water holding capacity, but it will not increase the water supplying capacity much. Clay holds water so tightly that plants are not able to get it. For a little more trivia, soil organic matter simmilarly holds a great deal of water but does not release it thereby increasing the water holding capacity but not the water supplying capacity. What organic matter does do is improve the soil structure creating pore space that holds and supplies water. Again I would be hesitant to add clay. There is the potential to create problems associated with clays without increasing water supplying capacity at all.

Clays used in pottery are 1:1 (aluminum to silica) layered clays that do not shrink or swell -otherwise the potery could crack when dried. These are not sticky clays and have low (for clay) CEC's.

Also, sand does not evolve into silt. Sand evolves into clay. Clay is a secondary mineral that forms from the chemical weathering of primary minerals. Silt (which holds and suppluies water far far better than sand or clay) is a result of physical weathering. High silt soils come primarily from glacial weathering.

Again, if you are going to add clay, add a very small amount. But what you are really need for improved water supplying capacity is silt.

fertilizersalesman, that was the whole purpose of the Rodale thing, their new/old composting technique is suppose to enable compost to mix with sand better with a higher CEC. The page is not old, and it does have pictures.

In my last post I did make two mis-statements; the confusion about clay/silt/soil, and raised beds. I meant lasagna bed. Thanks for the heads up, so good to not be perfect.

Again, since I do not plant in sand I am not qualified to comment about adding raw clay...

Blutranes

Blue,

I finally broke down and read the Rodale page. I was thinking it looked kind of familliar then I realized I have seen those experiments when I was at Rodale. They were adding clay in an effort to catch nutrients that are lost in the composting process. Interesting, but I would not say it relates to adding clay to a sand soil.

Sand compost clay will be bound together by the soil organisms at work in the whole process leading to structure that does it all.

Let's take a closer look at that Rodale article. Yes, I read it. Now I'm gonna tear it apart.

Rodale makes a point to tout their "patent pending" amended compost as superior to a standard for the reduction of nutrient loss. They say the superiority is most noteable under high rainfall conditions. It is that part of the study I consider. See the graphic below.

Their study includes three mixes of 20 cu yd. The Mix 3 is all manure and under downpour conditions had a total N loss of 18.3 lb, or 0.915 lb per cu yd. The total P loss was 74 lb, or 3.7 lb per cu yd. These rates of loss will be applied to the amount of manure used in the other mixes.

Mix 1 was the standard mix of 5 cu yd of manure, 15 cu yd of leaves. The 5 cu yd of manure should give up a total of 18.5 lb of P and 4.575 lb of N. Since the mix total loss was 3.1 lb P and 1.14 lb N, we can determine the absorption rate of the leaf portion to be 1.03 lb per cu yd of P and 0.23 lb per cu yd of N.

Mix 2 was the "patent pending" one containg 4 cu yd manure, 14 cu yd leaves, and 2 cu yd clay. The 4 cu yd of manure gives up a total of 14.8 lb P and 3.66 lb N. As seen in the graphic the nutrient loss from the pile is almost zero. But if the rate of retention by the leaf potion is calculated, it is no better than that of the standard Mix 1. Would anyone like to guess at why Rodale put 5 yd of manure in the standard mix and only 4 in the "patented" mix?

{{gwi:317298}}

Adding clay to compost may or may not reduce nutrient loss, but the Rodale study proves nothing. The organic nuts are no better than the chem companys when it comes to spinning their own version of truth.

Makes me wonder if we are going to see some "magic" clay for our piles on the store shelves next year.

pls8xx,

You were a lot kinder to Rodale what I was on another post. Rodale can't even keep the grass off the concrete. They are using the same technique Sir Albert Howard used in 1920 in India. Howard used what he called urine earth because the soil was full of calcium. He also inoculated his piles with more mature compost, while composting in pits. I have made compost using his technique since I first learned about composting. I tell you what, If you can get your hands on urine earth you will find it is the most powerful amendment there is IMO. My main issue was all these Ro-ganic gardeners telling everyone not to add soil or clay to their compost. While I am watching compost mature almost in front of my eyes to a certain extent. The second half of the discussion is on the "Humus" thread; the beginning is linked in that thread...

Blutranes

"Makes me wonder if we are going to see some "magic" clay for our piles on the store shelves next year."

And will it be earthenware, stoneware or porcelain? ;~)

Althea, what you need in your soil much more than clay is organic matter. To make much, if any difference, in your sand you would need to add about 20 percent, by volume, clay and that is a lot of clay and will be very expensive. Work on getting the level of organic matter, which is mostly free in your area, built up in your sandy soil and forget the clay.

Kimmsr, 20% clay?
In sandy soil the bottom is still porous so the 20% will still leach out, the only clay of value is that which could be tied up with the sand in the top soil area.

So, a small amount added over time with a lot of organic matter will tend to be bound with the sand and organic matter by the soil organisms. If of course you are not tilling which messes up the organic process.