@Rickcorey I think Amber needs help with her clay soil, the daylily help has been given. Many blessings to you!

Good link, Larry!

Here's a simple example of "the soil triangle". But beware: it's a little like USDA Hardiness zones. The soil triangle ONLY talks about "texture". Size of grains. It specifically is NOT about the second-most important factor to garden soil (organic content).

http://www.oneplan.org/Water/s...

Probably our intuitive associations with each "soil texture class" are based on our unconscious assumption that the soil ALSO has a reasonable amount of organic matter from compost or decaying humus.

But the "soil triangle" wouldn't distinguish between rich, fertile, organic "silty clay loam" with 8% OM and abundant soluble and slow-release NPK, vs. sterile inorganic "silty clay loam" that had had every microgram of organics and nutrients leached or burned out of it. (*) The soil triangle is only about texture.

As with USDA Hardiness Zones, if you want to know something USEFUL, you have to combine the soil triangle with OTHER factors, like organic content, temperatures, grade, rainfall, salinity, microbe populations (helpful or disease), mineral nutrient content, pests ... ad infinitum.

I think this is why people say (wrongly) that "clay soil plus sand equals concrete".
Actually, it should be "clay soil without any compost really stinks for gardening
and is rock-hard whether or not you add sand or even grit."

Clay without compost is for making bricks and ashtrays.
Adding or subtracting sand or grit is almost irrelevant for gardening
until you get up to half sand and grit, or 70% sand and grit.

Clay plus compost still drains rather poorly -
but clay plus compost PLUS GRIT AND SAND
drains and aerates a heck of a lot better than just clay plus compost.

Anyway, that's how it works in my yard, even if other people had other experiences. I do mix and "fluff up" my clay-compost-sandy grit and then firm it again gently, and it only lasts a year or two before it slumps down again, but I can grow things in it during those years, and then add more compost and fluff it up again.


(*) I think that if you had ENOUGH organic matter that was still particulate instead of soluble, the soil triangle would recognize the organic matter - and treat it exactly like crushed granite of the same particle size. But my impression is that you can hardly keep soil organic content above 5-7% unless you're adding compost and mulch several times per year. If you feed microbes that much, they will multiply and eat it faster than you can add it.

Well, faster than I can add it. I have to buy it and wheelbarrow it around, and seldom have more than 1" to add at a time.

Thank you, Sharon.

Umm, if I used coir again, even outside, I would rinse the heck out of it first. Some cheap vendors have salt in their coir ... I don't know, do they float their coconuts in the ocean or something?)

>> I also intend to prepare a bed for seedlings which will be planted next spring. Would I use the same products to amend the soil in the seedling bed as I would in the bed for the larger DLs?

Again, I think that's a fairly technical question about daylilies. I know nothing. I would try to narrow down whether I had almost no N, or some strange reason the tube didn;t have any color at all. Have other things grown vigourously there, to indicate it is already fertile?

Many plants' seedlings do NOT want much fertility if you want them to grow stocky and healthy. So MAYBE low fertility is what you need ... again, I would listen to those with specific relevant experience.

I found this about coir saltiness:

http://www.madehow.com/Volume-...

>> the coconut palm tree (Cocos nucifera). Before being shipped to market, the seed is stripped of an external leathery skin and a 2-3 in (5-8 cm) thick intermediate layer of fibrous pulp. Fibers recovered from that pulp are called coir.

>> Fresh water is used to process brown coir, while sea water and fresh water are both used in the production of white coir.
Read more: http://www.madehow.com/Volume-...

>> The husks of fully ripened coconuts yield brown coir. Strong and highly resistant to abrasion, ...
>> white coir comes from the husks of coconuts harvested shortly before they ripen. Actually light brown or white in color, this fiber is softer and less strong than brown coir.

I guess most of it is shipped from India and Sri Lanka

-
Also: http://www.fao.org/docrep/005/...

Traditional method:
>> highly polluting of surface waters and results in the accumulation of large dumps of pith.
>> generally in ponds of brackish waters (for three to six months) or in salt backwaters or lagoons. This requires 10-12 months of anaerobic (bacterial) fermentation.
>> yield the highest quality of (white) fibre for spinning and weaving.

I just learned: If I quote someone else who flagged my name as "@RickCorey", I get a system notice that "Rick Corey flagged your name in a post".

Post #1227889 (12)

And now I'll get another.

I know that it is very wide-spread to say not to add to add sand to clay soil. But since the only "why" given is a cute reference to concrete (which is made with MORTAR and aggregate like crushed stone plus large gravel - not clay). That never impressed me. Argument by analogy is for poets, not scientists or engineers, farmers or gardeners.

If they had said "adding sand OR GRIT to clay soil that has ALMOST NO COMPOST OR VERY LITTLER COMPOST does not help much", I would agree with them. But what that really means is: "clay soil needs compost!"

AFTER you've added ALMOST ENOUGH compost to lighten the clay soil significantly, THEN try adding 15-20% very coarse sand and grit.

Then believe that the results you get under your own conditions are the answers that are most relevant to your garden.

What I see when I do it in my yard contradicts the cute sound bite that I hear repeated over and over.
So I go by what I see, not what I hear.


>> When I do this, I replace almost all of the clay, so only maybe 10-15% of the soil that is left is clay

I also remove all the soil from my "raised and sunken" beds, so I can slope the "floor" towards a slit trench that utilizes the grade to escort water from the sunken part of the bed to a lower part of my yard.

But then I screen it repeatedly to break up the clay balls and mix the clay with compost, bark, grit and sand. I amend it with as much of these as I can: compost, crushed stone, bark fines and even sometimes the coarsest sand I can find.

I add very roughly as much amendments as clay soil. For my best beds, more than 50% amendments. When I run short, maybe only 30% amendments ... but that isn't enough.

I think I start with "clay soil" that's at least 60-70% clay and 0% organic. I amend it until I wind up with maybe 30-40% clay, 30% bark fines and undigested compost fibers, at most 10% grit + sand, plus as much compost as I can afford (up to 20%? I wish I had 50% compost, plus another 3-4" to add every year.)

I let it "digest" for some weeks or months if I'm patient, before dumping it back below grade (but trenched). That also lets me watch it settle while it "digests" and decide whether I need to buy more bark and compost. Crushed rock and sand are SO expensive and heavy that I very seldom get more than 10% sand and grit added. But when I really need good drainage, like one well-drained square yard for bulbs, I use a lot more grit and bark, and then it drains great for around 1.5 to two years.

(After the compost and bark are digested, I have to fluff it up a again and add more compost. Maybe that's what scientists really mean when they say "don't". But until I find their papers, I can't really comment on the reasons for their conclusions.)

When I added a lot of crushed stone and bark and compost and a little sand, pure dead clay gave me excellent drainage for two years, then it subsided by almost a factor of two. Things will still grow in it, but it's HEAVY again. And my solution for subsidence would have been more crushed stone!

RickCorey said:I just learned: If I quote someone else who flagged my name as "@RickCorey", I get a system notice that "Rick Corey flagged your name in a post".

I think you won't get a notice for this one. You contaminated the flag with the quotation marks "@RickCorey". A space after/before the quote marks would have cleared it up for notification. Like a link to a webpage, it needs to be free standing for the flag to work.

Good comments about the clay. I have clay to work with - all kinds - smooth, gritty, mostly red but some gray and yellow - and I've used sand ranging from fine, smooth blow sand (the grains are rounded and tiny and won't lock) to fairly coarse sharp sand. The key is copious amounts of organic material in conjunction with using sand. It's the operative ingredient. As you say it doesn't last long, even with a high percentage of organic added. Clay, at least what I have, will consume considerable quantities of organic material. Gritty clay is a bit easier than the other types and I've always suspected it contains more organic material even though it's not visible. Clay is just hard to work with. Pick axe hard when dry and like stiff chewing gum when wet. I don't worry much about adding anything except organic material to change the texture.

I was told by a soil scientist that it is true that adding sand to certain clay soils can result in a worse soil texture than you started out with. The problem with adding sand is that you have to add it in such large amounts, something like 50:50 sand:clay soil or even higher to actually make a difference. Organic matter is best for amending both sand and clay. To quote the Royal Horticultural Society:

"Adding grit, sand or gravel to clay soils:
Clay particles are amazingly dominant in a soil. This is explained by the relative size of the different particles (clay, sand and silt) that soil contains. Clay particles are very small but, because this allows more particles to fit in any given space (say 1cm cubed), they have huge surface area that dominates the physical properties of soil. In comparison, sand and silt particles are larger, so fewer particles are needed to fill a space (say 1cm cubed again). As a result, the overall surface area of sand and silt is smaller and so much less influential on determining the characteristics of a soil than the clay particles.

In practice what this means is: to dilute the proportion of clay in a heavy soil requires very large volumes of grit or other material. It is seldom feasible to do this on anything but a small scale and, for most gardeners, other options such as raised beds, adding organic matter and choosing plants that thrive in clays are more practical.

Even where a clay soil contains for example 40 percent clay particles (a relatively modest content compared to heavy clay soils), the proportion of clay in the top cultivated part of the soil would have to be reduced by half to make the soil easy to work. This would require 250kg per sq m (460lbs per sq yd) of grit or gravel. Adding materials to clay can also make the clay less stable, so the soil becomes harder to manage. Experimenting on a small scale at first is recommended to be sure that any additions are worthwhile and won't have damaging effects on workability of the soil."

From: https://www.rhs.org.uk/advice/...

Donald, you're right that the adjacent quote broke the notification.

>> The key is copious amounts of organic material in conjunction with using sand. It's the operative ingredient.

I agree. Especially with the word "copious" (even if I have trouble spelling it).

>> I don't worry much about adding anything except organic material to change the texture.

I understand how that would work, as long as you add a LOT of OM and keep re-applying enough to keep the clay grains or micro-plates separated.

I should probably stress even more that my experience is with not enough compost. Like 20-30% compost is not enough to "redeem" clay even briefly. 50% compost - maybe.

But 20-30% compost, plus 10% grit and coarse sand (whether I add it or there was already some in the clay soil), THAT works pretty well for me.

Hi Sue

>> The problem with adding sand is that you have to add it in such large amounts, something like 50:50 sand:clay soil or even higher to actually make a difference.

I agree - if the soil has only a very small amount of organic matter. I think of that as "not enough OM to work", because buying OR wheelbarrowing 50% crushed stone, grit, or very coarse sand is just impossible for me.

If they did a test like "start with very heavy clay soil containing almost no sand or grit or OM", and then added 5% grit/sand, 10% grit/sand, 15% grit/sand and 20% grit/sand, then still found that the soil had worse drainage and aeration with increasing amo8unts of sand, I would be very surprised (based on my observations of MY clay).

I understand why a materials scientist would assume that clay+sand was harder and stiffer than clay - the idea of a plastic matrix making a composite material with solid grains stiffer than the plastic material would have been on its own is a basic assumption and usually true with engineered composite materials. And, probably, if you packed and pounded the sand and grit and clay down as tight as you could, maybe it would make a fine concrete until it got damp and oozed away. (Is that what adobe is?)

And a real soil scientist is probably assuming "soil for field crops", with tractors and cultivators and ten-ton-harvesters rolling over it repeatedly. That situation is different from my situation: raised beds 2-3 feet wide fluffed up like an omelet every few years while I talk to it lovingly to encourage it not to slump back down next year, either.

Clay grains are sticky, and flow together to exclude air. Composite materials engineers don't have that to worry about, but if they thought about it, they would cheer that the material was making itself denser and harder.

What matters most to the soil in my yard is not anything that concrete designers worry about: the material slumping and flowing together: voids filling with clay instead of either air or water. If someone designing a composite material sees voids, he or she promptly changes the processing method to eliminate the voids. Those voids, pores and tortuous crevices are what I am trying to encourage to sustain themselves for more than a few weeks. That's where the snad and grithave been helpful to me.

That said, if someone offered me 6 cubic feet of compost OR 6 cubic feet of crushed stone delivered to the sides of my beds, I would probably take the compost, even if the crushed stone cost 2-3 times as much and weighed ten times as much, and lasted 1,000 times as long.

Because I agree with the most important factor: you need a LOT of compost to redeem clay.

Unfortunately, 6 cubic feet of compost, at 50% compost, would only treat 12 square feet of bed (a 3' x 4' bed) to amend the clay 12" deep with 50% compost. Maybe I should have asked for the grit instead: at 10% grit, I could amend 60 square feet 12" deep with 10% grit. Then I could buy and carry more compost and have a 3'x 20' bed.

>> like stiff chewing gum when wet.

When I first started amending my current yard, I had forgotten the trick about wetting clay before trying to dig it. I was CHIPPING away at the clay and rocks with a big pick! Duhh. Yes, it gets even heavier and sticky when wet, but you don;t have to chip it like flint.

sooby said: ...
Clay particles are amazingly dominant in a soil. ... Clay particles are very small ...
... they have huge surface area that dominates the physical properties of soil. ...
... the overall surface area of sand and silt is smaller and so much less influential
on determining the characteristics of a soil than the clay particles.

In practice what this means is: to dilute the proportion of clay in a heavy soil requires
very large volumes of grit or other material. ...

That was very well said. You can also look at the soil triangle and note what a LARGE area is all called "clay". That's because, any soil with more than 35-40% clay just plain stinks ... until you dilute it with OM, silt, sand and grit.

I think it also matters a lot that soil with too much clay is FLUID as well as sticky. First it flows into gaps and pores or crevices, then sticks tightly to what it touches. Sometimes I found myself "dusting" clay balls with medium sand until they looked like little candies dusted with confectioner's sugar so they wouldn't stick together. But that's over-optimistic: as soon as the4y got wet, the clay balls would ooze all over the dusting and "consume" it. The clays needs ENOUGH stiffening grit and OM that it CAN'T flow easily.

sooby said: ...
... Adding materials to clay can also make the clay less stable, so the soil becomes harder to manage.
...
From: https://www.rhs.org.uk/advice/...

The words "less stable" are what I would have highlighted in that article and then gone researching their work for what else they had to say. If by "less stable", they mean that inadequately amended clay FLOWS and OOZES and compacts itself and STICKS to itself and anything else, and squeezes out air spaces as if it had its own tiny hydraulic ram - - - yes, I want to subscribe to their blog.

Yes. That's what happens and that's the whole problem. How to prevent that without spending my whole 401-K on bags of "coarse" sand and crushed stone, or adding 4-6" of compost every year.

I'm pretty sure any professional would bust a gut laughing at me when I described "fluffing the soil up like an omelet" every few years.

But that IS practical in my situation, whereas buying "enough" compost or grit isn't.

I guess the scientific experiment would be to spend equal amounts of money on buying and transporting and tilling in varying %s of OM and coarse stuff. Maybe each experiment would spend an equal amount of money, or replace an equal amount of clay with "the mix". Then test whether 20% compost + 5% sand is better than 25% compost and no sand ... a year later.

We would have to argue about using my wacky "fluffing" technique. A soil scientist would probably rather test PRACTICAL procedures, defining "practical" as whatever his or her funding agency wants to focus on. Like traditional agriculture in large fields using mega-tractors.

>> to dilute the proportion of clay in a heavy soil requires very large volumes of grit or other material.

I totally agree. But the scientists then seem to assume that, because it was necessary to get the results they wanted, that everyone CAN follow their advice and add 50% compost, or 50% whatever.

If you invert that and ask "what combination of materials can I make work on a TINY SCALE with repeated hand loabor every few years, I get a different conclusion than soil scientists who are speaking to big-field farmers.

>> It is seldom feasible to do this on anything but a small scale

Agreed. And I can't do it even on a small scale unless someone else does the wheel-barrowing and subsidizes some of the cost.

>> and, for most gardeners, other options such as raised beds, adding organic matter ...

Exactly. Maybe even "of course". Have they addressed the case where you are NOT adding "very large volumes of grit or other material", but only adding the amount that you can afford and transport, like 5-15%? I understand "that's not enough" to do the job all by itself.

But it's not "either-or". We don't have to choose between "50% sand right now" and "30% compost twice a year forever". 5-10% sand and grit, plus 30% compost now, plus whatever I can afford later, makes usable soil, and I can afford that.

And, in the subset of this exception to what they are mainly talking about that applies to me, I even have a hard time getting enough organic matter into the beds to do the job all by itself.

I never heard anyone address the relative merits of combining different amounts of compost, sand and grit when you can't afford 50-70% grit OR 50% compost added every year.

In that sub-sub-subset that applies to me, I've found (or I imagine) that I get better results when I add a little grit and snad to as much compost as I can afford.

And I don't think anyone would argue about adding as much compost as you can afford to any pitiful clay that had less than 50% sand and grit. At least we all agree about that.

@RickCorey and @sooby. Thank you so much for the very educational replies. Can you clarify please what is meant by "silt" and "grit". If I wanted to add these two things to my soil what would I actually purchase at the garden center?

If I am understanding correctly, you are saying that even though I amend my soil now and plant in it, that I will have to amend it again in a few years? Is that practical to do with daylilies? Would simply adding a 2-3" layer of compost on the surface of my flower beds each year be sufficient to provide the ongoing nutrients my soil will need?

I will send my soil off to have it officially tested. Sue, you mentioned that there are many types of nitrogen that need to be tested for. How do I know if they will test for all of them? This is a list of the types of tests (and their cost) that my local extension performs...which ones do you recommend I get?

Soil analysis Analysis cost
Regular analysis: pHs, NA, OM, Bray I-P, Ca, Mg, K (includes grinding with recommendations) $10
Bray 1-P or Bray II-P (with regular analysis — $4) $5
Mehlich III or Olson P $5
pHw or pHs(with regular analysis — $2.50) $5
Neutralizable acidity (NA) and pHs $6
Sodium (with regular analysis — $2) $5
Zinc (with regular analysis — $4) $5
Fe, Cu, Mn (with regular analysis — $4.50) $6
Nitrate (with regular analysis — $4) $5
Ammonium (with regular analysis — $4) $5
Nitrate and ammonium (with regular analysis — $8) $9
Sulfate-Sulfur (with regular analysis — $4) $5
Boron $5
Organic matter $5
Particle size analysis (percentage sand, silt and clay) $12
Electrical conductivity $6

Is it time to introduce the use of gypsum in conjunction with clay? I have known several people who were gardeners that swore by it. Especially it's application on clay over a period of years. I have used it off and on, but truthfully I was unable to notice that it altered the clay to a more malleable state. However, my use has been sporadic. It probably has never been over a long enough time frame where it's supposed to effect things.

I amend my soil several times a year by adding a layer of compost or mulch. That is a great way to do it and let the worms work it into the soil. Also you end up not turning the soil and bringing the weed seeds to the surface.

Donald, gypsum only works with certain kinds of clay, kinds that most people don't have:

https://ag.arizona.edu/yavapai...

Amber, silt is a normal component of soil, which is made up of sand, silt and clay plus organic matter in various proportions. Soil texture relates to the proportions of sand, silt and clay in your soil. I wouldn't add grit to garden soil. If you add sand I don't think it would need topping up but it also won't do much good unless you add huge quantities of it in proportion to your native soil.

Yes adding 2-3" of compost every year or two is the way I would do it. If you're starting a new bed you could incorporate compost, otherwise topdressing it is the way to do it without disturbing the roots and it will work its way in as Larry said.

Which soil tests to get depend what you have already done and if you have a problem you want to solve. If you don't suspect an existing problem the regular test should be all you need. If you really want to test for nitrogen you could add the nitrate and ammonium test. Most of the time we just assume nitrogen is needed. That still doesn't tell you how much organic nitrogen may be in the soil that hasn't been converted yet, but for the most part that isn't available to the plants at the time of the test anyway.

You can test soil texture (proportion of sand, silt and clay) yourself. This article explains how:

http://www.ext.colostate.edu/m...

If you think you may have overfertilized then the electrical conductivity test might be relevant but otherwise I wouldn't bother.

I also wouldn't bother with the micronutrient tests (zinc, boron, Fe, Cu, Mn) unless you've seen symptoms of a deficiency such as interveinal chlorosis. If you have, often we can figure it out based on symptoms and soil pH. For micro problems a leaf analysis would be more helpful or, better yet, both soil and leaf. Usually micronutrients become less available to plants as the pH increases.

I can't think of any way to buy silt.

I look for the coarsest sand possible, but have never found a bag that was more than 30% COARSE sand. So instead I buy crushed stone for coarse sand.

Actually, for grit-sized particles, I use pine bark chopped and screened. Lighter, cheaper, holds more water and gradually adds organic matter.

Grit can be bought as crushed granite grit, as #2 chicken grit. But look for the 50# bag "back in the warehouse". Don't let them sell you a half-gallon bag of grit for almost as much money as a 50# bag!


Clay, silt and sand are mostly about particle size, although it seems that particles small enough to be called "clay" are usually one of a few kinds of minerals also called "clay minerals" that break up into very thin, flat platelets that have highly charged surfaces. These minerals grab soluble plant nutrients like NPK and micro-nutrients when available in excess, because they have charged surfaces. Then they release the nutrients when their concentration in ground water falls lower. They buffer the nutrient concentrations and slow down their leaching away. Clay isn't all bad, in moderation! ("Moderation" is around 10-15% clay!!)

Once source "clarified" that silts are fine-grained soils that do not include clay minerals. I think it was Wikipedia that said that the word "silt" may be used differently by geologists, soil scientists, sedimentologists , colloid chemists and geotechnical engineers.

(I'm not positive, but I think that high-quality "rock dust" might be even smaller: colloidal dust, smaller than 1 micron. Colloidal particles tend not to settle out of water.)

Clay particles are smaller than 1-2 microns, but apparently sedimentologists just have to be difficult, and use 4-5 microns as the breakpoint. A micron is 1/1,00th of a millimeter. Say, "smaller than a bacterium". Clay properly so called is also one of several specific minerals: "Clays are formed from thin plate-shaped particles held together by electrostatic forces".
Clay feels slippery or slimy rubbed between fingers, and it settles very slowly in water.

Silt particles have sizes from 1-2 microns (or 4-5 microns) up to 63 microns.
Another system says "1/256 mm to 1/16th mm" .
USDA decided that sand starts when it won't pass through a #200 sieve (75 microns).
Silt feels "like flour" when rubbed between fingers and settles rather slowly in water.

Sand particles range in diameter from 0.0625mm (1⁄16 mm) to 1 or 2 millimeters.
Sand feels "gritty" when rubbed between fingers and "sinks like a rock" when it settles out of water.

Some people call it "grit" above 1 mm, others call 1-2 mm "very coarse sand".

Above grit, I only know gravel, pebble, cobble, stone and boulder.

" These minerals grab soluble plant nutrients like NPK and micro-nutrients when available in excess, because they have charged surfaces".

The clay minerals generally have a negative charge so they would attract the positively charged ions (cations). That's why nitrogen in nitrate form tends to leach more (negative charge) than ammonium nitrogen (positive charge). The major cations would be potassium, calcium, magnesium and sodium. Phosphorus has a negative charge as does sulfur. The micronutrients are a mix of positive and negative.

Does clay have a ph tendency?

cottelpg said:Does clay have a ph tendency?

Clay can vary, it depends on the amount of acid forming cations, like hydrogen and aluminum, as opposed to basic ones such as calcium, magnesium, sodium and potassium.

sooby said:" ...
The clay minerals generally have a negative charge so they would attract the positively charged ions (cations). That's why nitrogen in nitrate form tends to leach more (negative charge) than ammonium nitrogen (positive charge). The major cations would be potassium, calcium, magnesium and sodium. Phosphorus has a negative charge as does sulfur. The micronutrients are a mix of positive and negative.

Good point, Sue. Clay is probably only a good buffer for negatively positively charged plant nutrients. {Edited to change "negatively" to "positively"}

As to pH, clay mostly reflects what has been in solution around it recently. You can make it more acid or more basic.

But as a buffer, it RESISTS pH CHANGE much more than sandy soils. That might be partly the huge surface area of clay: its particles are just 1-5 microns in diameter, so they're "all surface area" compared to sand or even silt. Solid particles that don't dissolve only contribute to chemistry what's on their surface. A bag of big rocks has very little surface area on those rocks, compared to a bag of sand or a bag of clay.

So when a New Englander limes his soil with Dolomite lime, he lays it on pretty thick since he has rather acid, very clayey soil. If someone with sandy soil had acid soil (perhaps from acid rain), she would use around 1/8th as much lime as a clay-bound gardener would. Clay is a string pH buffer. Sand has almost no buffering.