When amending a clay loam soil to be sandy loam, for use in a garden bed, what kind of sand should be used? In a container environment, we would be restricted to larger particles of horticultural sand. For in-ground use, I guess we can tolerate much smaller sand particle sizes.

Do you specifically want sandy loam or is the goal of amending it more accurately getting things like looser soil with better drainage?

If it's the second sand may be a bad call for amending it. Larger grains help prevent turning your heavier clay into something like concrete but it can still take a massive amount of sand to avoid making things worse. It might take as much as a 1:1 clay to sand mix to avoid it.

Tilling in a lot of organic material can help break up the clay and give you better drainage. That can be things like compost, yard and kitchen waste in a trench composting hole, tilled in cover crops, leaves, finely ground wood chips, coco coir or peat. Ignore the concept of no-till, which strips the nuance from trying to preserve soil microbes, until your soil is in better condition. Those heavy clay deposits are near dead zones for soil microbes currently. That organic material gives you a mix of good drainage and water retention.

I use a lot of non-composted stuff in trenches in fall when I am putting the garden to bed for the winter. It's been breaking up my clay nicely. The side benefit is that I have bred healthy sized worm colonies by doing what is effectively in place vermicomposting. (Peat, coir, or already composted material is less effective at feeding them.) They keep digging around breaking things up further as they do their business.

Once you've got loamy soil you can transition to sandy loam if you want less water retention and even better drainage. Fix the clay first then amend with sand. I've seen the potential concrete-lie results when my sister jumped straight to the end and added sand. You almost certainly don't want that.

pone31 said: When amending a clay loam soil to be sandy loam, for use in a garden bed, what kind of sand should be used?

My understanding is that this isn't something that should be attempted.

Maybe talk to us about what plants you intend to grow.
My personal experience is that clay will grow most things better than sand, due to the ability of clay to retain moisture and nutrients.

There are plants that will not grow in clay...
For those specific plants, you would probably have better results by building a bed on top of the clay and filling with sand...

Incorporating sand into the clay seems doomed from the start...
Everything I've read about mixing the two seems like it would be contraindicated.

Edit:
I just read your previous post about clay raised beds...
Ok... I'd read it previously... didn't really have much to contribute to a post that seemed directed specifically at @tapla

We probably need specifics here before we'll be able to provide information that will help you.

I can't tell if you are interested in theory, or in growing something.

To give you some specific results that I experienced...
I once did some gardening in some very sticky clay.
I got immediate results by turning the garden into raised beds... No borders were required...

As long as I was adding organic material, results were good... But the clay remained sticky.

When I brought in some manure that had sand mixed in... the results were not what you would expect... Instead of turning friable, the beds kind of hardened.

But... maybe your results will differ... be sure to take lots of pictures.

Agreed, I have also read you really cannot add sand to clay and MAKE sandy loam.
And clay is not a death knell. Read more here..

https://today.oregonstate.edu/....

Informative article

PattyPan said:
If it's the second sand may be a bad call for amending it. Larger grains help prevent turning your heavier clay into something like concrete but it can still take a massive amount of sand to avoid making things worse.

If we go by the famous "soil triangle" then you need between 60% and 80% of the soil to be sand to qualify as a sandy loam. Certainly I would want at least 50% sand otherwise why bother.

I am NOT amending garden soil. I am interested in using a sandy loam amended with organic content for use in a raised bed.

stone said:
Maybe talk to us about what plants you intend to grow.
My personal experience is that clay will grow most things better than sand, due to the ability of clay to retain moisture and nutrients.

As per my last reply I am not amending the ground soil. I am developing a raised bed and want to try sandy loam amended with organic material. You can make sandy loam out of clay loam, as long as you know your starting fractions of clay, silt, and sand, and choose the right end target for sandy loam, which I think is around 60% sand, 20% clay, and 20% silt.

For those specific plants, you would probably have better results by building a bed on top of the clay and filling with sand...

That's what I am doing. Sandy loam in a raised bed over native clay loam soil.

Incorporating sand into the clay seems doomed from the start...
Everything I've read about mixing the two seems like it would be contraindicated.
...
To give you some specific results that I experienced...
I once did some gardening in some very sticky clay.
I got immediate results by turning the garden into raised beds... No borders were required...

As long as I was adding organic material, results were good... But the clay remained sticky.

When I brought in some manure that had sand mixed in... the results were not what you would expect... Instead of turning friable, the beds kind of hardened.

By experiment, I find that once the clay fraction in a soil mix gets above about 20% the soil tends to harden when dry. The traditional soil triangle has sand at around 60% to 80% of the mix, and the clay fraction never goes above 20%. So it's interesting that this triangle agrees with my empirical experimental results.

I would never try to amend hard clay soil for an in-ground planting. That's fighting Mother Nature and the amount of material required would be huge. I think building beds over the soil is a much better strategy if you have something that will not grow at ground level in native soil.

sallyg said: Agreed, I have also read you really cannot add sand to clay and MAKE sandy loam.
And clay is not a death knell. Read more here..

You definitely can amend clay loam to create sandy loam. The mistake people make is to not add enough sand and end up with a soil mix that is much more than 20% clay. That will harden when dry.

https://today.oregonstate.edu/....

I have to point out that farmers manage their soil for an organic content of 5% to 12%: very little organic material goes a long way. In a raised bed the situation is somewhat different since you have better drainage. In a raised bed you can get away with higher organic percentages.

pone31 said: As per my last reply I am not amending the ground soil. I am developing a raised bed and want to try sandy loam amended with organic material.

But... still no mention of what you intend to plant.

It seems like you already know what you are going to do...

Please take pictures.

stone said: But... still no mention of what you intend to plant.

It seems like you already know what you are going to do...

Please take pictures.

I would grow pretty much any plant in a raised bed, adjusting the pH where appropriate: Camellia, elderberry, conifers, and any herbaceous perennials to dress up the bed.

I did know what I wanted to experiment with: growing in a sandy loam amended with organic material, in a raised bed. The original question I asked was what type of sand can I get away with using. Somehow we went in other directions, which is fine.

If you can find 'sharp' sand it might stay open better. As opposed to smoother particles like river sand.