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Clay Soil to add or not to add sand...that is the question.

Edinburg, IL(Zone 6a)

I have read lots about soil amending but there seems to be a lot of conflicting advice. My soil is clay, thick and sticky when we have continuous rain and hard as concrete during a drought. Some advice says DON'T add sand because it will become like concrete. Some advice says DON'T add peat because it will remain soggy longer. I know compost is best. Every fall I pick up several truck loads of fall leaves that people have put by the curb for the city to pick up. I shred them with my leaf eater, put in piles and spead over the garden in the spring [even if it is only slightly composted] and till. I intend to continue doing the leaf thing as long as I garden. I have large gardens and I am rather impatient so I need to know how to convert the soil that I have into ideal soil only much much faster. Is sand a good idea and if so, how course should it be? Should I forget the peat? I am willing to spend the money for loads of sand, manuer, compost or whatever it takes.

Cincinnati, OH(Zone 6a)

I mulch with leaves in the fall and by spring my soil is crawling with big fat worms. My clay now has a huge network of big worm tunnels. Maybe you could try mulching with those leaves in the fall rather than tilling in spring. Let the worms come for the leaves.

If I were going to spend money on truck loads of something, it would be compost. First mulch with a couple of inches of compost in fall, then mulch with the leaves.

I have seen a big improvement in my clay soil by doing this in the past few years. I don't till or use chemicals. Maybe you could give this approach a try for a couple of years and see if you like the results.


Kirkland, WA(Zone 7b)

I have clay-based soil as well. I will never use sand again - it turned those areas into sandy clay with a cement-like texture. Peat - well, hard to keep it wet enough.
I would second kq's suggestion about leaves - You'll get great results in the long run. Remember that gardening will test your patience on every level, and as far as soil goes, if you don't take the time to provide good soil for your plants, you will more than likely have unhappy plants & more work on your hands down the line.
The worms will do the work for you if you give them something to work with. Do you have a source for spent coffee grounds nearby? (Starbucks bags theirs up & gives it away for free)
I have had great results doing the following:
fork into the soil lightly to break the top 4" or so, and layer whatever you can get your hands on: coffee grounds,shredded paper, grass clippings, leaves - there are never enough leaves! I top mine off with bark or wood chips - it keeps it all in place. The worms will come & help you out here, but it requires a little patience. Hope this helps.

(Sheryl) Gainesboro, TN(Zone 6b)

I totally agree with what has been said above!!! The K's have it!

Kirkland, WA(Zone 7b)

Only because i tried to rush things too many times in the distant past. I have learned much from experience, but the most valuable was learning to practice patience.
First: Soil - you just can't rush it. If you have access to great a supply & quantity of compost, that might speed up the process. But most of us don't. I really feel for those who have purchased new homes where the land has been scraped, and sits devoid of topsoil. Especially with neighbourhood covenants & all that accompanies them. The pressure & necessity to lanscape according to the rules can be daunting.

Second: - don't rush the juvenile garden. We can't expect our new or young gardens to look like those that are commonly featured in those glorious garden books & magazines. I hear so often people feeling poorly about their landscaping because it looks sparse. In other words - allow it to grow at a natural pace, give it the very best care possible, feed the soil in such a manner that your plants will benefit. I have encountered less problems this way.

(Sheryl) Gainesboro, TN(Zone 6b)


But Katye, I want it NOW!!!!!!



Kirkland, WA(Zone 7b)

I was thinking about this question today, and wanted to apologize if i sounded harsh to anyone, but particularly to Eden.
It would have been nice to have had access to a place such as DG when I first started into my gardening adventures some 30 years ago. But, aside from reading a lot, I tend to ask questions and then run with the most logical answer. I too, was told to add sand to my clay soil.
Sand does drain well, but in my experience, does not bring optimum results, particularly to a very dense clay.
The whole point of providing good soil is to grow healthy plants. The time & energy expended in soil preparation will save you time & energy (& frustration) in the long term.
It was such a waste to have to redo a huge area, and disappointing as well. So, in posting, it was my intent to hopefully spare anyone from having to go through this.
After I have amended with leaves & coffee grounds, leaves & grass, leaves & manure, etc., etc., I will typically achieve the soil consistency I want, depending on what I'm going to plant.
As far as peat goes, I have used it with mixed results. I prefer sawdust, composted with the leaves/grass whatever...

Pagancat - I want it NOW, too. Not only that, but I want it ALL, NOW!
How very cool it would be to live where you could grow everything - no zones allowed!
Oh, the dreamer's dream...
Summer was fleeting this year, and this is no Autumn tease. ColdWet has arrived, along with Greydays. Oh well - time for garden book & seed catalog reading!
Wishing you all a very fine weekend!

Greensboro, AL

Ive been reading about how soil is made. It is made from the action of rain on fallen plant matterial--leaves, twigs, branches. In a forest this is called "litter" and a whole bunch of forest animals live in litter, rooting around in it, eating and digesting it and excreting it, and the result is a nice thick layer of humus that feeds the trees who dropped the leaves to make the litter in the first place.

That is the process you are trying to mimic when you add compost to your soil. Humus, that's what you want.

Alexandria, IN(Zone 6a)

I have clay/silt/loam and either fine sand or screened river sand works well with my soil to loosen it. Actually my soil is good to start with, but I have made raised "beds"....without edging to better grow melons, watermelons, potatoes, and carrots. I have also added a lot of peat moss too. I get this peat from a local bog. It comes very hydrated and dryness is not an issue, but rather it is nice, loose, and slightly moist at all times...plus well drained. This peat is spagnum but rather a better form for gardening.

Course...all the organic matter you can get is vital to soil building and soil maintenance.

This message was edited Sep 2, 2011 3:09 PM

Edinburg, IL(Zone 6a)

Thanks all.
I think I will step up the amount of shredded leaves I put down. The people in the city do all the work for me by bagging up fallen leaves so all I have to do is load them up, take them home, and shred them.
I visited the Missouri Botanical Gardens today and noticed that they were doing just as Karen said. They put down a 3 inch layer of shredded leaves and grass clippings that were slightly composted.
Good advice, thanks...I will forget about the sand.

Tempe, AZ

Note also that many sand products you can get have a relatively uniform distribution in their size. This is not ideal, as the sand will sort itself and result in a pattern which holds a lot of water, thus increasing drainage problems in clay. If you must use sand, and it may be reasonable to do after a few years of amending, try to get some of the sand that is used on baseball infields, sometimes known as 'lava sand'. It is very heterogenous in size, and does not sort as uniformly, thus leaving airspace for drainage. Combined with extensive amending, year, after year, you will notice a change. For me, in hard, heavy and anoxic Arizona clay, it took approx 3 years for my soil to loosen sufficiently to allow a sparing use of sand in some spots that actually did GOOD things for my soil. Previously, sand + clay = concrete.

Greensboro, AL

Dreamer; where do you get the lava sand?

Edinburg, IL(Zone 6a)

DesertDreamer, I will take your advise. You explained it well and it makes sense. I will focus on compost for now and some sand later.

Ozark, MO(Zone 6a)

Leaves are great and I use large quantities of them, but grass clippings are also very good to amend clay soil. One of the best things I've done was to get the grass catcher accessory for my riding mower and start using the clippings.

In the fall, I also pick up and compost leaves that way. We have a bunch of big oak and hickory trees, and we get truckloads of leaves. I mow over them a couple of times without the catcher, and that chops the leaves up fine. Then I put the catcher on, mow again, and dump the chopped-up leaves in the compost pile.

McLean, VA(Zone 6b)

I agree with everything that was said about leaves and compost. I would add that in order for me to work a new section of my garden I found the addition of "soil fines" to be essential. "Fines" are simply really fine mulch - in my case hardwood. Adding this to the soil allowed me to dig without using a jackhammer. As with everything else, it will also breakdown over time, and further enrich the soil.

Within a five minute period I went from barely able to push the shovel into the soil to moving with ease when I added the fines. It basicly serves to loosen the heavy clay soil. In your area it may be listed as a soil conditioner, but it is basicly mulch. You don't want to overdo it, but I think it is fantastic when your shovel is stuck solid!

Tempe, AZ

Lava sand can be purchased from your local 'compost' source. Most large cities have a company that they contract with for composting their yard waste, which the company then sells back to the public. Many of these also provide material to contractors, including various grades of sand. If you cant locate anything under the 'building materials' section of the yellow pages to suit your needs, try asking the local parks and rec dept. about where they source their material for the infields of the local baseball diamonds. That material is usually very similar to lava sand.
Ive found a few sources around PHX. It cheap, you just have to ask around a LOT before people figure out what you are talking about.
Between massive amounts of organic material, lava sand, and a judicious use of Turface, my soil is turning out very nice. Im happy.

Anderson, SC(Zone 7b)

I have extremely hard clay with no top soil on it, and the very first layer I put in, under everything else, is a heavy dose of Gypsum, watered in. Gypsum loosens up the clay.

Right now I'm only using it under the lasagne beds or individual plantings I'm doing, but I'm going to start broadcasting it on the lawn shortly. Maybe eventually I'll be able to plant something right in the ground.

(Sheryl) Gainesboro, TN(Zone 6b)

Mmmm - I wonder if your clay is so hard because of the drought conditions? Not that it's ever fun stuff, but you might want to pour some water on it before starting to dig.

Also, using cardboard as one of the first layers seems to invite the worms and loosen things up, too.

Anderson, SC(Zone 7b)

Hi Pagan,
No, this dirt is just this hard; putting water on it doesn't help much. I can stand, stomp, even jump on the shovel and it won't budge after the first couple of inches. Another poster from GA & I were talking about it in another thread, and she's seen it break heavy equipment (we're not too far from each other).

I put newspapers on top of the gypsum, then leaves, then all the other layers. I know the layering itself will do the trick, but I put the gypsum in to lead the way. ;)

Greensboro, AL

SCNewbie: When we did excavations on the Tennessee River in sticky red clay (the kind that goes PING when you snap a trowel agaist it) we used Viscuine i.e. fairly heavy black plastic after a rain. If no rain hose down the site with fire hoses. Let soak in then cover with viscuine. Check to see when the moisture has evened out--usually over night. This is called "conditioning" the soil so that it would be suitable for excavation and preserve the stratification and features that we wanted to record. In this condition you can slice a 10 cm deep thin slice off a soil matrix fairly easily with a sharp shovel.

We use cut-off shoves, sharpened several times a day.

We always covered our excavation unit with black plastic over night to keep it in condition for the next day's work.

Anderson, SC(Zone 7b)

Wow, that's an clever way to do it, but it would take me forever to dig a hole that way. HOWever, it does give me some ideas about some other parts of the yard. :))

My yard (about an acre) badly needs to be graded all over & leveled in some spots. I haven't been able to bring myself to get it done, tho, because of that freaking clay. All I can think is that I'd have to deal with either the dust or the mud, and both choices pretty much suck.

Greensboro, AL

You can get a sheet of viscuine that covers 25 x 25 or 30 x 30 ft. It really takes 2 people to fold and roll it up. But that way you could do smaller unit at a time.

Kingston, OK(Zone 7a)

Eden try a small section and see if this helps.
Use Turface to work into the clay. It is better then lava sand and is used in gardening and also on sports playing fields.
Find out where your school gets it. I get mine at a AG supply.

Anderson, SC(Zone 7b)

I have 160' x 10' of frontage to work on over the winter, to get ready for planting in the spring. I just got rid of the landscape lumber that was in there by advertising it on craigslist for free, but now I have to get rid of the weeds and scattered plants that are in it, so the viscuine might do the trick. :)

Greensboro, AL

There is also a process called "solarization" where you use clear plastic. If you have sunshine, it is supposed to sterilize the soil, kill weeds, and give you a surface ready to go.

Also, lasagna is a method of cardboard/newspaper + mulch. It smothers weeds and gives you a mulched bed ready to plant.

Anderson, SC(Zone 7b)

Yes, gloria, I've thought of doing the solarization on the frontage, too. Wouldn't the viscuine work the same? I do lasagne beds in the other parts of my yard, but this area is pretty big so I'm trying to find a less labor-intensive way to do it. I have lung disease, so it takes me a LOT longer to get things done than other people. lolol

Greensboro, AL

SCNewbie: Supposedly clear plastic lets the sun in so the soil is "solarized", while black viscuine excludes the sun light but it does intensify heat so it cooks the soil. ive used both methods and I don't see a difference in practice. The clear plastic lets you see what's happening. If there is a hole don't be surprised if something grows up through it!

Don't for get to apply the plastic after a rain, or after a day of running the sprinkler. The moisture provides a "medium" for the process to work, and some steam to make it more effective.

Edinburg, IL(Zone 6a)

Can someone tell me how Gypsum works? Can I use too much? Should I till it in or can it be broadcast?

Greensboro, AL


The amounts and how to's are here.

Edinburg, IL(Zone 6a)

Awesome, thanks.

Fredericksburg, VA(Zone 7b)

SCNewbie, I too have lung disease, so I can relate. How about trying some sheet composting in that large area? If you have access to a tiller, you can shallow till the area, that will flip up a lot of your weed seed and just start adding wet newspaper, grass clippings, leaves, you can even you use big pieces of cardboard to kill out the weeds. I don't shred the newspaper, just lay it down in layers and then wet it and you can do the same thing to cardboard. I just weight it down with some old bricks until it gets nice and soggy. It take the cardboard longer to break down, but it's killing weeds and works very well on quack grass, which is my personal none favorite.

Anderson, SC(Zone 7b)

Hi doccat5, Yes, I'm doing the sheet composting or lasagne beds (with newspaper) for my small flower beds scattered around the yard, but what a job this'll be for my front border. It's about 160' x 5', so it covers quite an area.

I looked at the solarization, but that has to happen during the summer months, so that's not going to work. If I do the cardboard, do you think that'll be broken down by next spring/summer? I'm buying the plants now, to put in in the spring.

Greensboro, AL

In the south there is usually enough sun year round for solarization.

As for the cardboard, water thoroughly before application. Then make sure the cardboard is wet, before applying mulch. Most people plant directly into the mulch. Doccat5 gives an excellent description.

Fredericksburg, VA(Zone 7b)

If you put your cardboard down nice and soggy or get it nice and soggy, it will breakdown and you will have a lovely time planting "purties" in the spring time. Just make sure you tag it down well. You'll be surprised at the worm activity under the cardboard once it gets rolling. Worms love newspapers and coffee grounds, but some of them are secret cardboard junkies. LOL In the mean time, you might want to give some thought to scrounging as many newpapers as you can get your hands on. I use them as a base for mulch around most of my plants. I really have to watch controlling the moisture as we have a very shallow well (as soon as I win the lottery, I'm gonna fix that), but I find it really makes a difference in controlling moisture loss. I also mulch everything heavily.
Check some of your local stores that sell big appliances...at lot of them will give you those boxes for hauling them off. You can use a box cutter and cut them to fit what you need. You could also use the cut off ends of clothes hangers to tag them down. I usually have more than I can use, donate etc, so I'll take a pair of wire dikes and make myself some homemade cleats to tag down various garden items. Just haul a piece of sandpaper to sharpen the end for a quick need stick in.

This message was edited Nov 12, 2007 6:01 PM

Anderson, SC(Zone 7b)

Kewl beans - think I'm going to do that. Thank you!! :)) Thank you for all your input, too, Gloria. ;)

Lakeland, FL(Zone 9b)

i use pine shaveings

Cincinnati, OH(Zone 6a)

And the cardboard doesn't need to break down before you plant. I have planted in fairly fresh lasagna, like a couple of weeks after building the bed with cardboard.


Plano, TX

are you familiar with eucalyptus mulch? would it be good to throw into the compost pile? it is being sold for only 1.50 for the 2 cubic feet and is said to deter bugs

Everett, WA(Zone 8a)

I agree with many that the first need is lots and lots of organic compost. Maybe even 50%. The cheapest source I found was bagged steer manure (aged or composted). And add more every year since it breaks down.

But, in my yard, that made a dense, wet clay + compost mix (not really soil) extremely poorly draining and with little or no aetration or crumb structure. While softer than the clay used to be, it still didn't crumble (wasn't friable). It held water forever, mostly in a surface layer showing no eagerness to drain. And after only one year, it started to revert to plastic, forever-wet, gooey sticky clay.

I think that soil needs something larger than clay and humus/silt to improve porosity.

Pine bark (shredded mulch or nuggets) might be good. Coir (chunks or shredded) or peat might help. All those will break down over enough years, so why not start out pretty coarse, like 1/8" or 1/4" (3-6 mm)?

I don't like shredded wood, after using soil conditioners that had too much of it. It gave structure, but lots of fungus and looked more like dry rot than soil. Probably the best place for wood is sawdust in a compost heap to balance sources of N.

But lately I seem to be having better luck adding sand - AFTER getting lots of organics into the clay. I'm undecided between relatively fine sand (play sand) or medium-coarse "multi-purpose" sand. Both seemed to help friability, drainage and aeration. Probably the "multi-purpose" is good enough by itself, since it includes a wide range of particle sizes.

I probably have only 10% sand in most of my beds, at most 15% (it's heavy and expensive). Where I wanted assured good drainage for bulbs, I think I did get it up to 20% sand, maybe even 25%. (Though I also threw in 4 cubic feet of commercial potting soil!) That now seems very well-drained.


Everett, WA(Zone 8a)

After more experience, I would urge against sand if you get crushed rock instead. Every form of sand I've seen had rounded grains that were too willing to pack together.

And even "coarse" sand is finer than what you want for improving structure.

Crushed rock from 2mm to about 4 mm now seems best to me for structure (impriving drainage and aeration).

I may be misled because I started using pine bark at the same time I bought a cubic yard of coarse crushed stone (which the dirt yard guy called "sand", but it wasn't). Bark fibers plus grit seem like a great combination: the bark has some long fibers, and the grit holds them apart so that a little bark adds a lot of air.

Another reason I may be worng is that I'm continuing to add more OM every year, and that certainly is the single biggest factor in improving clay.

So I THINK that crushed rock helps with drainage and aeration. But I'm sure it helps in combination with almost enoguh compost and pine bark fines.

And I've seen many times when screening raw clay with way-not-enough-compost, that mixing in 15-25% sand, finer than the crushed stone, does at least help the clay to form somewhat crumbly clods instead of just pudding

MAYBE coarse sand or even medium sand has some use when mixed well with the clay - MAYBE it does im prove friability so you can break clods apart instead or just stirring pudding.

If you can afford to make soil from 30% clay, 30% compost and 40% crushed rock, you don;t need any advice: you can have good soil structure right away, and good soil as fast as soil organisms can populate it.

But if you don't have enough compost AND don't have enough crushed rock or bark, the combination of some-of-each is better than any one of them alone. (In my opinion, based on just a little experience.)


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