Home Forums Hunting & Shooting Hunter's Campfire Clay Soil Amendments

I have a few spots in my garden that even after about 8 years of adding organic compost amendments could be used to make bricks. Plants that I set out are stunted, and barely grow roots beyond the size of the containers they're transplanted from.

At first I was thinking it was a nutrient deficiency or pH and the pH was high (8.0) but I've corrected that with elemental sulfur. And the CSU soils lab tells me the nutrients are fine and specifically advised not to add any more organic amendments at this time because the organic content is already high, and that accumulation of salts from fertilizer may be a problem.

Which squares with what I've been reading about clay soils, i.e. that they're very good at retaining nutrients but also good at accumulating salts from fertilizers, and also cause poor root development because some plants just can't spread roots in heavy clay..

So I'm looking at pelletized gypsum because everything I've read says organic compost is the best way to loosen up clay soil but that's not working.

Anybody had success using gypsum, and any tips for application or working it into the soil?

Powdered lime don’t do it on a windy day

Soil is alkaline here so I don't want to use lime.

After four years of hitting it with peat and compost, the pH was still at 8.

Some people just can’t grow anything . All kinds of stuff grows here in red clay.

Sand and potash.

Till in some sand to amend the clay, the deeper the better.

Got the same problem with Georgia clay - add peat moss.

Another vote for adding sand. I spread about 6" of sand evenly on my garden plot then ran the tiller over it. It has been the thing for production of fruit and vegetables that I have done to this garden plot.

LOL, Pard!!

Some parts of the garden do well, others not. Some plants do well, others not. This area is notorious for the clay soils, they formed from volcanic ash and they're not only [bleep] growing soils, they have high shrink swell.

And like I said above, I've been adding peat, composted manure, and other organics for years to the point that the CSU soils lab told me not to add more organics at this time.


And from what I've read, sand is a good amendment if you have loamy soil, but not if it's a really heavy clay with no silt like the one we have. All the local experts say don't use sand for these soils. They recommend organic amendments first, and then gypsum. I do appreciate the recommendations but apparently what works in a lot of places doesn't work so well here.

Sand...

No sand unless your replacing at least 50% of the clay soil with it.

Know anybody with chickens??

I used gypsum, but my pH was only 7.4.

I got it extremely cheap and broadcasted it, disk, harrow, fresh seed. I liked it.


I would consider daikon radish to loosen her up .

What’s your soil pH now?

My two cents. You are trying to change the texture of the soil from fine clay particles to coarser silt or sand. Adding coarse organic matter in the form of manure, straw or a cover crop that you incorporate is one way to loosen up the soil but it will be an ongoing process. You could bring in sand or silt as suggested but that would need to be incorporated as well and it will take a lot of it. Trying to change the texture on a large scale is difficult. Chemicals are not going to change the texture of your soil. However, nothing is impossible except skiing through a keyhole.

Clay is the finest of all aggregate materials... Twice as fine as silt actually...



To make compacted clay soil Loamy... Clay must be broken up with other materials.

If I was working your soil (without actually having any idea what actual soil you have (See USDA soil maps for your region via the Web).

I would break the soil to a solid 2' of depth and commingle wood chips (from a wood chipper business)... several tons... as well as a LOT of sand (and possibly even cinder). Peat moss is also a fine organic (but not cheap in the volume you will probably need).

The wood will decay (and from a volume perspective... 80%+ "disappear").

Local arborist brings me 20-40 loads of chips a year free of charge. They become "Top Soil" in 2-4 years. (i.e. a 8' tall pile will be 10" of soil after the decomposition). During the decomposition the soil may be "too hot" to grow anything (be forewarned).

That is how I would fix the problem... maybe?

Raised boxes, filled with whatever soil you want.

Agree with the above that adding chemicals will not remedy your situation.

Heavy clay in places here in the Willamette Valley. I get dump truck loads of free leaves from the local refuse company when the streets are cleared in late Fall. 10-12' tall piles of this will get hot and compost. This compost has been great to remedy the clay, though it has taken some time. In Winter I put a foot thick cap of compost over the entire garden. By spring that has disintegrated into the soil, lightening it considerably as well as supplying fungal and microbe components. Can plant straight into it - haven't tilled here in over 20 years - then side dress everything with more compost. Keeps moisture in during summer and prevents any weeds. In my opinion peat is too light for what you describe.
Only other additions here are ag lime to raise pH and lots of chicken manure. Hot (straight from the coop) between the rows of garlic in February.

Try bowling.

vermiculite?

Several conundrums for folks east of the Mississippi. Eastern Kentucky, unless you are cultivating river bottoms is predominantly yellow clay soil. Around here, I have never heard anyone say that you can get too much organic matter (tilth) into clay soil. The more soil tilth you have, the better plants grow. Did a quick google search. Main issue that came up with too much organic matter is release of potassium. Unless you have a YUGE garden and are situated on a water course with endangered species, not clear how potassium run off from a garden is going to have significant impact. In re: high soil ph. Curious what "fertilizer salts" the CSU folks are concerned with? "My understanding", nitrates break down to form nitrites. Nitrites are highly acidic. Around here, high soil ph is self correcting. Two or three years of applying nitrate fertilizers, and the soil is so acidic that you have to spread 3-4 tons of ag lime per acre every few years to get anything to grow.

I wish you good luck with sorting out your garden. Curious how things vary from one part of the country to another...