improve heavy clay quick, cheap?

I am in the process of mulching and tilling my back garden. The soil is very heavy clay and easily gets water logged. i've been adding organic matter and sand but so far i've not seen much improvement in the soil. What is the best and quickest and cheapest way of turning the soil into good plantable soil. I'll be using raised beds but the raised beds will partly be the original soil i can't completely fill it with new compost as the area is too big so will be too expensive.

Personally I would definitely stop tilling it once you get the raised beds built, because tilling tends to damage the structure and cause compaction at deeper levels, making water-logging worse. Unless you can afford literally tons of compost, I don't think there's an instant way to build good soil. Just keep adding what organic materials you can find as compost and mulch and grow a variety of green manures. You might even trying concentrating at first on improving a smaller area with compost, while growing green manures on the larger area, putting your favorite crops in the most improved areas and gradually improving a larger and larger area each year.

Here's an inspiring video about making raised beds in a wet climate: http://www.youtube.com/watch?v=ugFd1JdFaE0

Of course there's also hugelkultur if you have access to logs....

And quit with the sand! Unless you bring in so much that your topsoil ends up being more than half sand, the clay will simply fill in around the sand grains and you will have something that would make good adobe bricks! Organic matter is the way to go. I would mostly lay this on as mulch and let worms or whatever incorporate it.
Especially beware when planting trees or anything else for which you mightl dig a hole into the clay. Be sure to backfill the hole with unimproved clay, and add any compost, etc. as a mulch on top. If you want to use humanure or some such that needs to be buried, make a separate hole beside the plant....the roots will find their way over to it at leisure. The problem is that in wet weather water will pool up in the more aerated loose soil right around the plant, and be very slow to drain off. Unless the plant is fully dormant and leafless, it stands a likely chance of drowning in a day or two. I eventually started planting a lot of things on shallow mounds against this danger. As the plant grows and establishes and the mound settles it becomes less of a problem.

This isn't really a quick solution and I hate to till, but in a pinch I'd rather till once than wait months for a garden in a new spot., but.. I created a new garden this year in some clay soil. Laid out about an inch or so of manure from nearby farm on each space. Tilled once. Planted as many beans as I could. Mulched, mulched, mulched, and mulched some more. The spots with beans are now the most fluffy and friable, i can reach my entire hand in easily where in the spring I could hardly poke a finger in there. Now if only there was no bermuda grass.... Seeing as it's fall and not much is going in the ground right now, I would just start mulching your area with whatever you can get your hands on, and make some compost for next year. If you have chickens they are great at shredding mulch and tilling for you, prevent pest buildup, and add their manure at the same time.

I would also second the buried logs/hugelkultur. The effort is well worth it.

I had similar problems with my heavy clay soil. Spent 3 years digging in leaves and pine needles to little effect and little harvest. It was just not enough, the clay was too much.

This last year I really put my shovel (and myself) to work and used hugelkultur and dug in wood chips, all free material. Fertilized with free "human liquid fertilizer".

My harvest was great and best in the combined hugel and wood chip beds.

With a lot of work you can take clay soil to highly productive soil right away, with free material.

My anticipation is that my garden beds will become no-till from now on, just using wood chip mulch.

Also definitely stop using sand.


This link shows pictures of digging in wood chips and stumps into the soil:

http://lowcostvegetablegarden.blogspot.com/2012/10/garden-bed-construction.html

monty ali wrote:I am in the process of mulching and tilling my back garden. The soil is very heavy clay and easily gets water logged. i've been adding organic matter and sand but so far i've not seen much improvement in the soil. What is the best and quickest and cheapest way of turning the soil into good plantable soil. I'll be using raised beds but the raised beds will partly be the original soil i can't completely fill it with new compost as the area is too big so will be too expensive.

I have had really good results with cover crops with my orange clay soil. I've used different seed mixes from Peaceful Valley Farm Supply, including a buckwheat/cowpea mix and their soil builder mix. The improvement in soil structure was amazing. In the lawn, I could stand on a garden fork, and it would go in maybe 2 inches. After one season of cover cropping, I could push it in the full length with one foot. In one case I started by turing the soil with a shovel, then planted, covering with a thin layer of compost. In another, I killed the grass, scattered the seeds and covered with a thin layer of compost. No tilling afterwards, just cut the crop down or let the winter kill it.

Alex

thanks for all the replies

I don't understand the no tilling idea? how do you plant in the soil without digging it? My garden is covered in grass and weeds...

I think i need to at least once otherwise i'll have to wait over a year befor i can plant anything. I have about a ton of sand and pebble mix left over from my building work on my house which is the stuff i have been adding. I have 3 compost heaps set up made from kitchen veg scraps, leaves, grass and twigs i turn them every 2 weeks or so but they don't seem to be cooking well especially the twigs. I have another compost heap made up from wood chips and leaves which is cooking brilliant it's the same stuff i've been using to mulch and mix into other parts of my garden.

Should i add all the wood chips an mix into the soil?

As well as the sand i've been adding bag fulls of chopped up paper and cardboard. Because i've not had a garden for so long i want to make the most of what i will have. So i want to be able to plant in the spring.


What is cover cropping? and where do you get free wood chips from? i made all my wood chips myself
I did have access to some huge logs just had them taken away though. I do have left over building timber some of it has paint on though i was going to use it for building the raised beds fire fuel

From what I understand the advantage of using mulch and green manure is that it allows the bacteria, fungi, and worms to help condition and break up the soil by providing food and keeping in some moisture. Plant's roots will also help. Some plants like Daikon radish will create a nice taproot, then rot away and create humus. When you till you actually cause more weeds to sprout up by mixing in and bring up weed seed. Of course you need to dig to plant. When soil lays bare the microbes populations decrease, if it's clay soil then it bakes in the sun. When you consistently have plants growing in soil it will help to create better soil.

thanks mate, i'm with you on constant growing, the area i'm trying to use at the moment is what used to be a lawn full of weeds. are there types of cover crops i can plant in november? i want to plant c=garlic and onions the planting season is comming up soon

Deep rooted plants are the way to go. I've had the most success with seed mixes heavy on vernal alfalfa. Super deep roots (up to 30ish feet) that get in and break up that clay, pull nutrients from down deep, and fix nitrogen from the air on top of it all. Planting alfalfa, lupine, radishes, burdock and the like with good, quick biomass producers like comfrey might do you well.

Hi there Monty,

I have been gardening on heavy clay in SE England for years and my encouragement to you is that you can look forward to a really fertile soil which holds water well once it has plenty of organic matter mixed in. To lighten your soil you can add lime (which I believe helps the clay particles flocculate; make sure it's the natural sort) and start making leafmould which is a brilliant soil improver. You can make it in a year if you are in a fairly damp climate, and if you collect the leaves from grassy areas by setting your mower blades to the highest cut and mowing over the leaves. This way you get a mix of chopped leaves and added grass tops, which add nitrogen and water to the leaves and mean that they are breaking down through more than just fungal action.

We made our leafmould heap like this last year and were amazed to find how good the product was after a year - usually it takes 2 years to get this far - and interestingly the leaves I had only raked up and added whole had definitely not broken down so well. Local reports say the appallingly wet spring/summer we had in GB helped!

I would also recommend using rock dust rather than sand - it contains all the volcanic minerals which a clay soil might be missing. Also lots of well-rotted horse manure.

The friends above recommending cover crops are also bang on - I grow overwintering broad beans (from which I get a crop in early summer). Not sure if you can do that where you are, our weather is probably more moderate than yours!

Good luck!

Hi Rosalind thanks for your advice, i'm having to restart my compost heaps so i'll be adding all the composted materials to the soil in the next week or so. In terms of lime can i add old plaster? I'm in leeds so we get a fair bit of rain. I've got loads of it lying around at the moment. I racked up all the leafs in my garden that have fallen and piled them up. Can i add green privet leafs?

I've ordered some alfalfa seeds and brad bean seeds but will i be able to get them planted and get them growing this time of year.

That depends on how far north you are, how cold it gets, and how tolerant those plants are to cold. At worst, if you sow them out now they might not sprout till January or February, but they should definitely still sprout (as long as nothing eats them, anyway).

How large is the area? It might be an idea to focus on one area at a time, or it can be a bit overwhelming.
I live on a sand dune and I'm not very familiar with clay, apart from wishing I had some!

monty ali wrote: the raised beds will partly be the original soil

Original soil is awesome:D

monty ali wrote: I have about a ton of sand and pebble mix left over from my building work on my house which is the stuff i have been adding.

As far as I know, people with clay are advised to avoid adding sand, as it can set like concrete.
I definitely wouldn't be adding pebbles.

monty ali wrote: Should i add all the wood chips an mix into the soil?

If they're 'cooking', I dunno, might be best to leave them to compost. I wouldn't dig chips into the soil unless I had a huge amount of really high-nitrogen stuff to mix it with, otherwise there's likely to be a pretty major nitogen/carbon imbalance for a while.

Hi Monty

You should be able to sow broad beans in Leeds now and they may germinate quite well if we do not get too arctic! You must get the right variety - I always use Aquadulce Claudia which are bred to stand over winter. They only fail if you have a warm autumn/early winter and then very cold weather after Christmas. This happened to us once - our beans were 10" high at Christmas with soft, green growth throughout a very mild December, then on 6 January we had a -10C frost and they all died overnight. If they start slowly they are hardier, and you can protect them with fleece if you are worried. Alfalfa needs to be sown in summer: http://www.organiccatalogue.com/Seeds-Green-Manures/c21_51/p363/ALFALFA-112g/product_info.html and although there are some other winter "green manures" (which is what they are generally called in the UK rather than "cover crops") they usually need sowing by September, which is always too early for me!

I would worry about using plaster - goodness knows what's in it, including perhaps fungicide. You can buy a bag of lime pretty cheaply from a garden centre (or Homebase or similar). Lots of good information here: www.gardenorganic.org.uk/. Also here: http://www.rhs.org.uk/Gardening/Grow-Your-Own where you can download a "when to plant what" information sheet.

Pebbles: useful for mulch on top of pots to keep the moisture in during hot weather. I wouldn't dig them in, although the very small kind can be useful if your clay really is solid and smooth.

Also, if you need some bulking material, try asking your council - they should be making compost and selling it. There is a particular grade of council-made compost called something like "Veridor" which is recommended as high-quality.

Also, early winter and early Spring are good times to plant shrubs and perennials, so if you are planning to put some in, with plenty of well-rotted manure, you could start quite soon. It's a good time to plant raspberry canes, too, for example, and you can plant small fruit trees in about February if the ground is not frozen!

Oh yes - and privet leaves. They would take a long time to break down as they are shiny and hard. They will break down, but not as quickly as the softer kind, so it might be better to stack them separately if you have room, or burn them if you're able to have a bonfire and spread the ashes on your soil.

Good luck!

Also... we have just planted overwintering peas too. Use Meteor or Feltham First. There are others, for example: http://www.organiccatalogue.com/Seeds-Vegetables-Vegetables-P-R-Peas-Autumn/Spring/c21_22_23_32/index.html. We just scattered them and poked them in 2" deep.

If your soil is pretty unimproved you may not get much of a crop, but they will fix nitrogen and you might get something edible! They need sticks or netting as support (I always use sticks). I've never sown autumn-sown peas before so am looking forward to seeing what happens.

Rosalind

There was a comment about adding sand to heavy clay soil. There is sand and there is sand. Vocanic sand is a porous sand. Common sand is a cube. Add these lttle cubes to clay and you can make some nice bricks Add vocanic sand to clay and you can increase pore space and help your plants. So with clay you will use worms to make holes and aggregates in the soil. You will plant tiller radish and other plants with roots that can grow into heavy clay to again make holes and this time leave organic matter other organisms can use. And you can add amendments to soil and subsoil to provide pore space. In heavy clay the limiting factor is generally oxygen.

What about clay soil but in a Mediterranean dry climate instead; I was reading an steve solomon book about dry farming; and he said that it was one of the worst combinations.

If we are talking soil structure then porosity it KEY.
We are talking micro, meso, and macro pores.
Adding a cube of sand does not greatly increase pore space.
Adding a porous material will increase pore space.
Meso pore has capillary action to bring in water, but does not hold the water so tightly that roots have a hard time obtaining this water.
Macro pores are key to soil quickly absorbing water and allowing water to make contact with meso pores.

Perlite used to increase porosity in clay soils.
http://library.greenocean.org/swglibrary/seaweedassoil/seaweedassoilref/effect%20of%20alglal%20fibre%20on%20varoius%20soils.pdf

Expanded shale used to increase porosity in clay soils.
http://www.dallasplanttrials.org/Articles/ExpandedShale.pdf
http://horttech.ashspublications.org/content/12/4/646.full.pdf

Biochar as a soil amendment.
webpage

Ceramic conditioner used to increase porosity in clay soils.
http://www.proschoice1.com/downloads/WP_Soccer.pdf

Coal fly ash used to increase porosity in clay soils.
http://www.ncbi.nlm.nih.gov/pubmed/11758395

Edited by moderator to shorten crazy-long link

I have heavy clay soil..see my blog below

I did top one somewhat hugel bed with clay soil one year by accident (my son and husband filled it when I wasn't looking)..and it is a real bear to work with. I still have been mulching and planting it but it isn't a very good bed..maybe someday it will be.

I continue to pile organic matter on top..but it fills up with weedy stuff mostly..the kale did well on it and the podding radishes and the lettuces were OK..but that is about all that survived (of course we had a horrible drought last year as well)

Brenda,

You may wish to try one of the Tiller radish family in the clay bed this fall. These daikon radishes may be able to dig into the clay and open gaps. The radishes will die in winter freeze and decay quickly in spring.
If you apply mulch when the radishes decay you can work in some organic matter along with the decaying radish into the soil. If you do this every year in time you should loosen up the soil in your bed.
Also if you are mulching you should in time get some earthworm action going. The right mix of earthworms will create tunnels and work organic matter into the soil. This should also help soil structure.

You may also try getting some cowpeas, sweet potato, beans, or other cover crop started and weedwaking the bed to knock down the weeds then putting started cover crop all over it to smother the weeds for a year.
Just make sure you use something that will not reseed and will die with the coming of winter.

alex Keenan wrote:Brenda,

You may wish to try one of the Tiller radish family in the clay bed this fall. These daikon radishes may be able to dig into the clay and open gaps. The radishes will die in winter freeze and decay quickly in spring.
If you apply mulch when the radishes decay you can work in some organic matter along with the decaying radish into the soil. If you do this every year in time you should loosen up the soil in your bed.
Also if you are mulching you should in time get some earthworm action going. The right mix of earthworms will create tunnels and work organic matter into the soil. This should also help soil structure.

You may also try getting some cowpeas, sweet potato, beans, or other cover crop started and weedwaking the bed to knock down the weeds then putting started cover crop all over it to smother the weeds for a year.
Just make sure you use something that will not reseed and will die with the coming of winter.

Radish dying over in winter doesn't work for everyone. I grow Daikon Radish as a winter crop.

Steve you got me there I keep forgetting that this blog is global in scope and covers many climate zones.

I never thought of having freezing winters a lucky before. However, it does allow me to use cover crops that cannot winter over.
If you live in a climate where radishes are a winter crop then the question becomes how do you get rid of the cover crop? Well there are a number of root crops that can get a foot hold into clay soils and expand. Daikon radish is just one of them. Several of these are tasty to pigs. In fact some people plant such crops as forage crops and let the pigs harvest them. To do this you need a pig species that is an active forager not the common massed farmed pigs. You will also need to train them young to respect electric fences. If all these conditions are met, you then grow your cover crop and let the pigs do the harvesting. I have seen pigs totally plow up an area mixing plants, pig waste, etc. into the soil. It looks like a real mess when they are done! But remove the pig and the ground is ready for planting. You can find a lot of information on pig tractors. I tend to use poultry tractors to clear areas out. With some crops I have had amazing luck with geese. They destroy dandelions, clover, and many other plants. My grandparents used them for weeding potatoes and strawberries for decades. My family has done this for generations. So you may want to think some plant/controlled foraging system.

From reading some of these comments and my own experience, putting in a hugel bed in thick, reddish-brown clay soil, especially in a dry climate can cause problems.

I'll be digging up some of my hugel beds from last year and redoing them this spring.

The problem is the logs aren't rotted yet and the clay is too thick to support good vegetable growth.
With logs close to the surface it becomes impractical to dig in more compost and organic matter each year.
And it becomes impossible just to loosen the soil as you definitely need to with thick clay.

For the new hugel beds I dug, I placed all the logs (vertical stumps actually to help with drainage) 8-12" under the top of the soil.
Now I can dig in more organic matter every year as needed using a standard shovel. And as the stumps rot, the lower layers will become
more organic.

Here's what I did in my Chapel Hill, NC red clay garden.

1. Check google maps for the nearest horse stables, dairy farm, etc. Manure from any herbivorous animal should be good. Maybe not goats though, I've heard they have lots of worms.
2. Call them up and ask if they're selling or giving away their manure, stable cleanings, etc. Any organic matter is good.
3. Get a truck or trailer and go pick up as much as you can. Some farmers will even load the manure for you. Make sure the give the farmer something for his trouble.
4. Till the manure and maybe some lime amendment into your soil as deep as you can. I try to double-dig and usually shoot for 2 feet deep. This is the only time I'll be tilling the soil so I try to over do it.
5. Level the soil higher than the surrounding grade (maybe as high as 6") since the soil will compact over time. Remember, it's always easier to take away than add more so shoot for a little too much.
5. Plant immediately. I've put plants into horse manure fresh from the animal and it was fine.

The results for me were outstanding. I had to water some in the first year but after that no irrigation was necessary to get great results. It was a game changer for gardening in clay soil.

Alder Burns wrote:And quit with the sand! Unless you bring in so much that your topsoil ends up being more than half sand, the clay will simply fill in around the sand grains and you will have something that would make good adobe bricks! Organic matter is the way to go. I would mostly lay this on as mulch and let worms or whatever incorporate it.
Especially beware when planting trees or anything else for which you mightl dig a hole into the clay. Be sure to backfill the hole with unimproved clay, and add any compost, etc. as a mulch on top. If you want to use humanure or some such that needs to be buried, make a separate hole beside the plant....the roots will find their way over to it at leisure. The problem is that in wet weather water will pool up in the more aerated loose soil right around the plant, and be very slow to drain off. Unless the plant is fully dormant and leafless, it stands a likely chance of drowning in a day or two. I eventually started planting a lot of things on shallow mounds against this danger. As the plant grows and establishes and the mound settles it becomes less of a problem.

Sand is not the problem, it is they type of sand you are using. Common sand is a cube block with no pore space.
There were a number of decades long tests done with porous material like flyash used on hiking trails.
It was found that around 20 percent to 30 percent flyash used prevented soil compaction. This is because you are adding a stable porous material.

I did a number of tests with Hosta over a decade ago using organic and porous materials.
The soil was a heavy clay soil and all the hosta were planted in the same sized holes.
I tested a number of soil amendments under trees with aggressive roots using a single species of host.
The hosta were left in place for years and finally remove and roots measured. In many cases the ones planted with organic amendments only had very short roots. The ones planted with stable porous materials had long stable root systems.
My results were published in a couple of magazines.
What I found was that there is a steady state that most soils will go to over time regarding organic matter content.
The highest tends to be at the mulch or leaf litter area and it decreases until you hit the subsoil.
When you plow or double dig you are forcing organic material to deeper layers. Over time this organic material will decay and if the decay rate is higher than the rate worms, plant roots, etc. can add organic matter than the percent of organic matter in the soil will decline. If you are depending on the percent of organic matter to provide the needed soil structure you will see a decrease in soil structure.

Now when I double dig I apply stable porous material such as perlite, expanded shale, porous sand, etc. I add this to the first and second dig. With this I now know I have forced mesa and macro pores into my double dig area. Since the upper layer will have a higher level of organic matter over time you will likely not need as much porous material. In my heavy clay I use 30 percent porous in the lower layer and 20 percent porous material in the upper layer.
I can now either plant deep rooted cover crop like tiller radish into this to increase organic matter to the level that roots can now penetrate. By doing this I am establishing organic matter at the depth that roots can penetrate on a repeated basis since I can add a deep root crop on my rotation schedule.
If my beds are only four feet across at a time with four feet on either side left alone I will get worms and other critters migrating into my new beds in short order. Once a bed like this is finished and the first deep rooted crop is done you will never need to till this bed again. You can use cover crops and mulch or a combination of the two. In some cases if the weeds take over you can just mow it short and cover with a heavy 5mil or greater weed barrier or tarp long enough to kill the weeds.

monty ali wrote:I am in the process of mulching and tilling my back garden. The soil is very heavy clay and easily gets water logged. i've been adding organic matter and sand but so far i've not seen much improvement in the soil. What is the best and quickest and cheapest way of turning the soil into good plantable soil. I'll be using raised beds but the raised beds will partly be the original soil i can't completely fill it with new compost as the area is too big so will be too expensive.

I will give you my experience. It certainly isn't the only way, and conditions do vary, but works for me.

I have some sandy clay soil here that was hard as a rock. I mean seriously rock hard. I just moved here to Oklahoma 5 years ago and wanted to start a garden. I did what I had normally done in those circumstance, got my shovel and garden rake out and tried to turn over the sod. The soil was so rock hard I was jumping up and down on my shovel like a pogo stick, and I weigh over 200 pounds. I literally tore up my shoes and my feet hurt so bad I really had no choice at all. I was forced to figure out some other way. Now I had been an organic gardener since childhood. So I was very familiar with Ruth Stout. I always mulched. But like many people I would turn the soil first, plant, then mulch. This time that just wasn't in the cards. My feet were so sore I could barely walk and I had managed only about 100 square feet turned over in a weeks worth of painful effort. Not a single worm was found. So I just mowed the rest of the area right to the soil line (scalped it) and laid down 6 layers of newspaper covered with grass clippings. Watered that down and planted a week later. Even in a week the soil was already noticeably improving. Even in the transplant holes I was starting to see worms. The no till section ended up doing far better than the tilled section. I have refined this quite a bit since, but the basic technique of weed barrier covered with thick mulch is basically the same. I can go out right now, 5 years later, and dig in the ground with my bare hands. The whole area is like potting soil.

I really don't think there is any technique that is easier, quicker, cheaper, or more effective than that. At least none I know of.

I moved onto a property with heavy compacted soil, drainage problems, and thick sod. I started a half acre market garden by myself with limited resources. Sheet mulching everything was impractical in terms of labor and material available. I bought a 60 year old tractor and several 50+ year old implements for not a lot of money.

What I did was plow the whole field using a moldboard plow right before winter. I left the upturned clods without harrowing. This allowed the freezing and thawing to break of the clods. And it did so amazingly well! The clay became dust that slipped between my fingers like hourglass sand. Erosion was a concern. I dealt with that by digging a swale and berm all the way around my garden. I may get erosion into the bottom of the swale, but no further. The swale also helps solve the drainage problem.



In springtime I used a tractor cultivator to make paths/drains between 4' beds.



Most of my planting was done by transplanting 2" soil blocks. I had to rely on these for most of the fertilizer my first spring. Throughout the season I added wheat straw mulch when I had it, all had to be purchased and hauled in. I planted buckwheat, daikon, and sorghum sudan grass as cover crops in some of the beds I was not using. They are champion! Field pea, turnip, and rye are pretty good too and those seeds are less expensive for me.

At the end of the first season going into the second winter I am not using the moldboard plow, only a subsoiler and a disc. Then I broadcast rye and field peas which are about 3-6" high at the start of Nov. I added about 30-40 tons of compost and manure through the middle and end of the season, which was simply not possible for me at the beginning of the season.

ben harpo wrote:
I moved onto a property with heavy compacted soil, drainage problems, and thick sod. I started a half acre market garden by myself with limited resources. Sheet mulching everything was impractical in terms of labor and material available.

You might check out my Red Baron project on the project page. Not saying it is the only method. In fact you could call it an experimental permaculture method. But I solved the sheet mulching problem scaling problem and now use it market truck farm scale. If I can find the right property for the right price, I intend to try scaling it up to full size commercial scale.

I completely agree with Alex. We have terrible clay here. I have applied a mix of old wood, gravel and native soil throughout most of the deep hole, then mix in compost above. Then I usually plant trees, bushes or other deep rooted plants so the roots and life can get down there and stay there. It makes a huge difference in the long run.
John S
PDX OR

Davin Stewart wrote:Here's what I did in my Chapel Hill, NC red clay garden.

1. Check google maps for the nearest horse stables, dairy farm, etc.  Manure from any herbivorous animal should be good.  Maybe not goats though, I've heard they have lots of worms.
2. Call them up and ask if they're selling or giving away their manure, stable cleanings, etc.  Any organic matter is good.
3. Get a truck or trailer and go pick up as much as you can.  Some farmers will even load the manure for you.  Make sure the give the farmer something for his trouble.
4. Till the manure and maybe some lime amendment into your soil as deep as you can.  I try to double-dig and usually shoot for 2 feet deep.  This is the only time I'll be tilling the soil so I try to over do it.
5. Level the soil higher than the surrounding grade (maybe as high as 6") since the soil will compact over time.  Remember, it's always easier to take away than add more so shoot for a little too much.
5. Plant immediately.  I've put plants into horse manure fresh from the animal and it was fine.

The results for me were outstanding.  I had to water some in the first year but after that no irrigation was necessary to get great results.  It was a game changer for gardening in clay soil.

2018.07.16 Update

I have been amending my soil for a few years now with kitchen scraps, worm castings, and local horse manure.  I've dumped in significant amounts of organic matter but my humic matter content is largely unchanged at 0.3 - 0.5% according to my most recent soil analysis.

I'm honestly at a loss as to why this would be.  The soil is visibly darker, fluffier, and easily dug by hand ... not like the native heavy clay soil that I started with.

The issue that I'm now facing is that my potassium and phosphorous levels are so high that they're off the charts!  So adding additional nutrient rich organic matter is not an option.  The county extension agent said that I honestly only need to fertilize with pure nitrogen for about 2 years to get the potassium and phosphorous levels back to normal ranges.

So after doing some research, I discovered that aged pine bark fines will provide significant organic matter without locking up nitrogen or providing significant additional nutrients.

Fresh wood chips would do the same but I've heard that they lock up nitrogen in the soil and harm plant life for a couple years unless supplemental nitrogen is applied.

Problem is that aged pine bark fines aren't easy to find and aren't that cheap.  ~ $2 / cubic foot ... also the quality is highly variable

Does anyone have any other options for adding organic matter to the soil without adding nutrients?

The method I use is cheap, easy, but it is certainly not quick.

Year 1
* Lay down cardboard, preferably 2 layers if you can.
* Wood chips on top of the cardboard, 4" or so.
* Sprinkle ammonium nitrate over the area.
* Lay fallow.

Year 2
* Repeat the year 1 process, water heavy.
* Seed with the cover crops of choice for the season and locale. Select crops with deep tap roots.
* Crop the cover as appropriate, reseed again.

Year 3
* By now you should have 6" of fertile top soil developing and a heavy residue cover to plant into.
* Pull a soil sample and you will find that the clay, still there, is changing color due to the root mass residue left behind by the cover crops.

To cover any serious area you need a viable source of chips and patience. But I find this easier than pounding a rototiller on hard Texas clay.

Howdy!
Yeah, trying to grow in clay soil is hard! There's a lot of really good organics in the clay, you just have to work with your soil to get to them.

I have Texas Black Gumbo clay. If I dug deep enough, there's a high concentration of sulphur and iron. Our well water is full of calcium, rust, and sulphur. It takes some getting used to and workaround.
I'm going to assume that others have offered you this same advice, or at least reasonably close to it (because I haven't finished what's already in the thread yet, but will after I share my experiences), so you may already have been given these tips.

We're not kidding. Stop adding sand. If you add sand to clay, you get adobe. It's great for building houses, lousy for trying to grow plants. It was old advice 40+ years ago when I first read that "You should add sand to improve drainage in clay soils". Complete BS. I know it's already been mentioned, but please Do Not add rocks or sand to your soil.
If you need to do something with that stuff, build a sandpit for your chickens, if you have any, and use any gravel or rocks for artistic paths or mosaics or something. Maybe make artful cement stepping stones of a table.

Free wood chips -  if you live in a more suburban area, or you happen to be friends with the tree trimming crews, you can ask that they drop off at your place. Where I live it's a case of "catch as catch can". If I *can* get to the crews (they come out for the county and the electric company, different crews, different styles), usually someone has already asked for the chips, but it's worth a shot. Most of my tree-like stuff comes from my trees. Sometimes I can get a neighbor's as well.

It's important to know where your mulch comes from, as well as what treatments it's had while growing/being chopped or whatever preparations were done. I know way too many people who have bought hay to use as mulch and ended up with a dead garden because the hay had been treated with some kind of herbicide. I usually only use my own carefully raked grass clippings as a mulch. And cardboard with any tape removed, or shredded paper, or ... I don't use wood chips as mulch because of the tendency of ants and rodents to move in - where I live at least - so I try other things.

Tilling versus No tilling - Here's where you can really get into some personal preferences and real issues. Generally speaking, if your soil is packed down from people driving or walking on it, or it was used as an over-grazed field, or was somehow otherwise compacted? Till it. Do something to relieve the compaction. I have to go out in heavy rains with my garden fork and punch holes in the soil where my "Very helpful" neighbor has mowed while the ground was still wet. Soil compaction prevents water from being absorbed by the soil and can cause horrible problems later.  Do what you need to do to prevent that.

I double dig when I'm first starting my beds because I live where it was an overgrazed field and then people drove over it with heavy machinery (and still use smaller machinery to be helpful).
I use a shovel, dirt fork, and tarp. I will dig out a two-foot (or so, it's a garden, not a rocket) hole for the length of the bed. That all gets dumped on the tarp. Then I move the next bit into the hole I made, incorporating good stuff with the soil I move as I move it - traditional double digging. Hard on your body, but worth it for the sense of accomplishment.  I only do this once unless it gets compacted again. Even then, you run the risk of hardpan forming underneath where you're digging. Garden forks are useful for punching holes in the hardpan. Once I've dug the bed, I'm done unless someone is silly.

With this most recent garden, I would start to double dig, giving myself a lovely hole, then I filled in the hole with sticks and chunks of wood and chicken poop and anything else that was biodegradable and seemed like a good idea at the time. Then I'd shovel the next row on top of that, giving me more lovely holes to fill up with biodegradable stuff.  Not quite hugelculture, but close.
This year - getting a late start, pulling weeds as I dug the holes and filled them in, I still have winter squash plants that have spread over the fence, into some shrubbery, and are trying to reach a live oak that's within sight of the garden. The sweet potatoes are a dream (as long as the rodents don't eat the potatoes), but the vines are lush and gorgeous and trying to cover the ground. The summer squash lost a fight with squash bugs, and the rodents ate the squashes, then the chickens got involved and ate the bush beans. So, I count it as a win. The garden fed someone living here and to turned into eggs which I enjoyed.

No-till is exactly that. You pick a spot, mulch the living daylights out of it, then plant into and through that mulch. If I leave my current garden alone until Spring, I'll probably no-till starting from then. I am actually planning to dig out the whole space and move an old "burn pile" into the spot as a slightly modified Hugel, then cover it in the soil removed.  A lot of work off the top, but almost no work for a while. In theory.

Start small. You will find that your garden can quickly outgrow your ability to manage it. I started with one bed in 2020, added three more in 2021. I'll be condensing them into one large bed in the Spring if all goes well.

I was paging through some of the other comments and you have some great people giving you great advice. Please, pick what works for you and try it. If it doesn't work, try something else. Keep trying. You'll learn something every year, and it's always interesting to see what happens.
I'm enjoying watching David the Good's YouTube channel (https://www.youtube.com/user/davidthegood ) . It's entertaining and I'm learning a lot about how to do different things, as well as how well certain theories work in Real World applications. He has sandy soil, the opposite of my clay, but the same solutions work for both things.

In my experience, there are a few things that can be solved by certain additions or subtractions, no matter the original problem - If you have a digestive issue, it can generally be managed with the addition of quantities of water and fiber, both soluble and insoluble. It doesn't matter if the problem is too easy versus too hard, the same solution works - add water and fiber.
Amusingly, to me, the same things work in gardens. If you want better soil add lots of biodegradable stuff. If you have sand? Add mulch and compost and anything else you can find. If you have clay, the same thing.
Water and fiber fix a multitude of sins.

I hope you have fun in your garden, no matter what you decide to do. That's the important bit. If you have fun, you'll do more of it. It means you're doing it right.
Best thoughts for a greener world!

Maybe shredded paper?
As far as I know, it has nothing other than bulk to add. I've used it as a mulch and have previously mixed it in with soil removed to get a lighter soil, but it only adds whatever is in the paper. I will soak it and let it get goopy, sometimes. Paper goop is easier to mix in if my experience holds true for you.

Good luck!

Kristine,

I have used newspaper as a top layer mulch to suppress weeds. But it degrades so fast in the south that sometimes one can be half way thru a bean season and wished you had put down more paper. :) My general preference is to get the cardboard if for not other reason than the worms love the glue and habitat it provides them.

Last time I tried putting down cardboard (and paper does degrade fast down here! I love it for that.), the chickens got into it. I still have chickens who hit the site of where I *had* planted potatoes, but the worms had moved in and the chickens dug up and ate everything. I have a pile of cardboard for the next time I decide to try that, and put a fence around it, but I'll wait until I feel more like that. Working on getting the beds together right now.

I hope your year is starting well!

One of the great things about these forums is the perennial threads.  They are like gifts that just keep giving.

This one was started back in 2012 and just keeps on giving.

There is so much great information given here.

I like to recommend wood chips and compost to help clay soils.

Here is a thread to help explain the difference between mulch and compost:

https://permies.com/t/166474/Mulch-compost

I also like to recommend reading Dr. Bryant Redhawk's Soil series:

https://permies.com/wiki/redhawk-soil

Especially this one:

https://permies.com/t/108953/improve-clay-soils-growing-year

LOL
I just had this conversation with my mother where I tried to explain that, because of her HOA, she would never be able to really improve her soil in a sustainable way unless she bought about 2 tons and had her yard, effectively, replaced. And that would still get her a few nasty letters, probably.
We talked about hugels and hugelculture. She loves the idea - saw it work out for me. Unfortunately, it's a no go.

In the course of talking about what she *could* do, I told her that all she really needed to focus on was somehow getting more organic matter into the soil. However she could. "Well," she asked. "What if there was a more sandy area and not just clay?"
Add organic matter.
"So, what are my options?"
Easy. You can add organic matter. Or maybe you could ... add organic matter. Or, just thinking out loud, you could try adding organic matter?

We both laughed. Gardening is easy once you figure out the secret. The hard part is the actual work! Now, time to get out and see what I can do about getting the hard part done a bit more ....