What the difference between Ocean sand and River sand

[rockm]

There should be no flat sides if you're using decent "sand" in your soil. This is the "sand" ingredient I use when making bonsai soil.

Mystic White II® Premium Swimming Pool Filter Sand

www.ussilica.com

 

[Cajunrider]

This article is very interesting.

Effects of Particle Shapes and Sizes on the Minimum Void Ratios of Sand

The minimum void ratio is an important parameter for evaluating soil properties. It is closely related to the compressive properties, permeability, and shear strength of soil, and it is affected by particle size distributions and particle shapes. However, existing research generally focuses on...

www.hindawi.com

 

[Leo in N E Illinois]

If you have a wide distribution of particle sizes, your mix will compact, it will not breathe. You will have low oxygen at the roots, poor water penetration and other related issues. If your mix is mostly 4 mm to 6 mm diameter particles, sand, 0.5 mm or less is a less than desirable thing to add. It will clog up air voids and cause drainage issues. Ideally bonsai media should be fairly uniform in particle size, no fines, no coarse chunks.

 

[Pixar]

If you have a wide distribution of particle sizes, your mix will compact, it will not breathe. You will have low oxygen at the roots, poor water penetration and other related issues. If your mix is mostly 4 mm to 6 mm diameter particles, sand, 0.5 mm or less is a less than desirable thing to add. It will clog up air voids and cause drainage issues. Ideally bonsai media should be fairly uniform in particle size, no fines, no coarse chunks.

The sand I'm using is really fine ( it's the finest sand I've seen from the East coast of New Zealand ) and I'm using less than 10% now in my soil mix . My trees seem to be happy so I'll continue to use it .
I'm going to collect some iron sand from the West coast of New Zealand ( the sand is really heavy ) I'll using it to add extra weight to a bonsai ( with prevailing wind etc...)

 

[Lorax7]

The sand I'm using is really fine ( it's the finest sand I've seen from the East coast of New Zealand ) and I'm using less than 10% now in my soil mix . My trees seem to be happy so I'll continue to use it .
I'm going to collect some iron sand from the West coast of New Zealand ( the sand is really heavy ) I'll using it to add extra weight to a bonsai ( with prevailing wind etc...)

Leo is right about how particle size affects packing density and AFP. Here's a study someone did that compares packing with uniformly sized spheres vs. 2 different size spheres that shows the resulting density of each packing. They did this in a different context (civil engineering), but the math is the same for soil particles. The TL;DR is: packings of uniformly sized particles are substantially less dense (leaving more empty space for air) than packings of 2 sizes of particles.

 

[Pixar]

The TL;DR is: packings of uniformly sized particles are substantially less dense (leaving more empty space for air) than packings of 2 sizes of particles.

Just remember the soil mix completely mixes the sand with compost & potting mix and a bit of sawdust ( so the sand particles are completely mixed ) you can't see a concentration of sand anywhere

 

[Lorax7]

Just remember the soil mix completely mixes the sand with compost & potting mix and a bit of sawdust ( so the sand particles are completely mixed ) you can't see a concentration of sand anywhere

Which changes nothing whatsoever about the analysis… Random packing (complete mixing) is what was represented in their model.

 

[Pixar]

And the sand will eventually wash down between the pumice layer and down to through the bark layer ( which is has layer of spagnum moss underneath )

 

[Lorax7]

And the sand will eventually wash down between the pumice layer and down to through the bark layer ( which is has layer a spagnum moss underneath )

…thus increasing the density of those layers, causing them to lose air-filled porosity and have drainage problems eventually.

 

[Pixar]

Seems to drain just fine when I pour water into them

 

[Lorax7]

Seems to drain just fine when I pour water into them

…for now. How about in another year or two when the organics in the mix are breaking down and the sand migrates downward and starts to compact at the bottom of the pot?

 

[Pixar]

How about in another year or two when the organics in the mix are breaking down and the sand migrates downward and starts to compact at the bottom of the pot?

My bonsai are reasonably small , so I'll be re-potting by then

 

[Leo in N E Illinois]

The most traumatic thing we do to our bonsai is repotting. Root pruning often takes a year or more to recover from.

In general, exhibit quality bonsai should not be repotted more than once every 5 years, possibly less frequently. If your choice of potting media forces more frequent repotting, you are building in set backs to your bonsai development.

Do as you like, but you should rethink your choices for potting media.

 

[Taste]

Wonder why we have Pine trees growing as forest in river and ocean sand ? The forest has been there for years

Because it’s not in a container, and the roots can reach for better soil.

Sand is one of if not the worst soil component that could be used in a soil mixture. It’s non porous, will get cold quicker, hotter quicker, will compact the soil.

As others have said you seemed to have made your mind up. But whole honesty. If you can use anything but sand do.

Pumice, lava rock are my main components, some bark if needed, and maybe some charcoal in my drainage. Sand is only good for use in humidity trays, stone displays, and sand specific designs.

In michael hagedorns book bonsai heresy he has a part about sand as a soil good read.

 

[Pixar]

We must be silly here in New Zealand we grow Pine tree forest in the stuff

 

[Taste]

We must be silly here in New Zealand we grow Pine tree forest in the stuff

its just one of those things where yes, it may work, but theres better ways of doing it.

 

[Lorax7]

We must be silly here in New Zealand we grow Pine tree forest in the stuff

You are indeed very silly if you think growing a miniaturized tree in a container is the same as growing a full sized tree in the ground. Here’s something to ponder: Water pools at the bottom of a pot where it meets with the impermeable barrier of the ceramic container. Where does the water pool when a tree is growing in the natural environment in the ground? What are the distances involved? What are the implications in regards to drainage?

 

[Pixar]

Water pools at the bottom of a pot where it meets with the impermeable barrier of the ceramic container.

Water drips out of the drainage holes of the pot ( I'm using normal bonsai pots )

 

[Lorax7]

Water drips out of the drainage holes of the pot ( I'm using normal bonsai pots )

Some water remains. Water a tree thoroughly and wait until it has stopped dripping through the drainage holes in the pot. Then, tip the pot at an angle. What comes out of the hole? More water. Why? Because there was water perched on top of the impermeable ceramic bottom of the container.

 

[Pixar]

Water pools at the bottom of a pot where it meets with the impermeable barrier of the ceramic container.

Water drips out of the drainage holes of the pot ( I'm using normal bonsai pots )

Because there was water perched on top of the impermeable ceramic bottom of the container.

So that's three layer below the soil mixture ( pumice , bark & spagnum moss )
I really don't see a problem