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Silica sand

  • Thread starter xantius
  • Start date
So after much searching, I have managed to find 2 sources of silica sand in my area. One is .50 grain and one is .20 grain. Do I want smaller, finer sand or larger, coarser sand for CP's?

Xantius
 
The recommended size is a 16 mesh (US) sand = 1.20mm

Try pool/spa filter sand from a pool/spa supply or horticultural sand from a garden supply.
 
Why is this the recommended size exactly?

The recommended size is a 16 mesh (US) sand = 1.20mm

Try pool/spa filter sand from a pool/spa supply or horticultural sand from a garden supply.
 
It's readily available. #16 and #20 seem to be the most commonly used grades for sand-blasting.

If the sand is too fine it eventually separates from the peat moss and washes out through the drain holes. This can lead to hollow spaces in your pots where the roots can dry out. Finer grades also compact more, forming a dense mass.

I use #20 because I can get it for free. It's a little finer than I'd like but works well with Drosera and Dionaea. I would use a coarser grain then #16 with larger plants but #16 is ok for them.

From what I can tell from photos of sandy CP sites is that #16 approximates the average grain size, but then it is difficult to judge accurately with out a scale of reference (other than the plants).
 
After trying every other type of sand I could find, I finally went to a pool shop and bought a bag of #20 grade silica sand. However, they say on the bag that the effective size is .45-.55mm. I've used it for 7 months now, and it has worked wonders. The grains are larger than you'd think. I don't know if this is a mislabeling on their part, based on what NaN is saying, but it is working perfectly fine for me so far. I originally used horticultural sand, but it was basically chunks of rock for ten times the price.
 
That's good to know. Home Depot has a 100lb bag of silica sand for about $7 US. It said on it the following:

surface profile 3.0
effective size in filtration .5

I'd assume that it would work. What is the proper method for "washing sand"?
 
I am unfamiliar with the terms but if you can see a sample if the sand and it looks around 1mm in diameter it should be ok.

Be sure to wear a dust mask/respirator when working with silica sand that is not wet or has not been thoroughly rinsed. The silica particles can cause severe damage to your lungs (silicosis).

I don't think there is a proper way to rinse sand, just what ever method you find that works. For large amounts I fill a sturdy bucket up to half full of sand then push a water hose to the bottom of the bucket. I then turn on the water with enough force that the sand gets agitated without spilling out of the bucket. Pouring out some of the water as it fills will speed up the clearing. Holding a board over the opening as you pour will help you to keep most of the sand inside if you tip it a little too far or the sand shifts. It probably helps to turn off the water when you pour. Rinse until the water is clear (it usually has a tan hue at first).

Rinsing is very important as salts are often used in the grinding process as well as removing small silica particles.

Some people rinse the sand with vinegar or other weak acids to help remove the salts. I've found vinegar to cause other problems such as fungus/bacteria growth. Your Mileage May Very.
 
Hi xantius -

I was eyeing the very same bag - it was all I could find. It's is an awful lot, I wish they sold it in 50 lb bags.
 
Play sand comes in 50lb bags. It's pretty much the same stuff, just pre-washed a little better.
 
  • #10
Play sand comes in 50lb bags. It's pretty much the same stuff, just pre-washed a little better.

I always use play sand from home depot and my plants grow fine in it. I don't even wash it before use. I wouldn't worry about it too much... it's only sand! :)
 
  • #11
I would recommend rinsing all media you use. Collanders also work, depending upon what you are rinsing and the hole size. I've also used rag towels spread out on a small trampoline.
 
  • #12
So Jim brings up a good point. I'm having MAJOR algae problems in nearly every pot. I can only figure that either the perlite or the peat has something in/on it that is fostering this kind of problem. Pots with most or all LFS have little to no algae.

Do any of you actually rinse peat?
 
  • #13
I rinse peat. There's a lot of dust in there. If not for algae or unwanted moss, then for potentially toxic chemicals.
 
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