sand vs. vermiculite/perlite

[dice]

Expanded shale research results:
http://www.ashs.org/index.php?option...xes&Itemid=145

[outsiders71]

Ami: What do you think of pool filter sand?

Dice: Thanks for the link and info on the expanded shale. I think i'll try both shale and pool filter sand in my mixes this year.

[amideutch]

outsiders71, try to get the coarsest grain size as possible. I think it runs between 0.5mm to 1.0mm. Ami

[outsiders71]

Anybody know anything about Hydroton Clay?:

http://www.plantlightinghydroponics....er-p-1443.html

[Polar_Lace]

Originally Posted by outsiders71

Anybody know anything about Hydroton Clay?:

http://www.plantlightinghydroponics....er-p-1443.html

Googled it:
Information taken from a web Search:

Hydroton or "expanded clay," is a lightweight gravel which is manufactured specifically for hydroponic cultivation. This media is the first choice for many commercial Dutch growers specializing in flower and vegetable cultivation. Not to be confused with many other kinds of expanded clay which look similar but which are often toxic, Hydroton is pH stabilized and releases practically no minerals into the nutrient stream; in other words Hydroton is almost completely inert - except for offering excellent moisture and oxygen capacity to stimulate healthy root development.

~* Robin

[outsiders71]

Sounds like this stuff may be beneficial to my peat:silica sand mix.

[amideutch]

Basically this is a standalone inert aggregate used for growing plants hydrponically in pots where a constant nutrient level is maintained. It doesn't break down and it remains as long as the plant does. It's quite common here in europe and I'm growing a rubber tree in it. It's a little bit expensive to use for one season unless you want to go through the hassle of separating it and cleaning it so you can use again. Perlite is a lot cheaper and has better water holding properties than this product. Ami

[matilda'skid]

I am also looking for something cheaper than perlite. What do you think of scoria (landscaping bubbly volcanic rock).

[dice]

[scoria]

Red volcanic rock may lower the pH over time, so if you
reuse it, you probably want to check the pH of your
planting mix long enough before planting to add some
lime or wood ash if necessary (wood ash breaks down
fast and will quickly raise pH; lime takes months to
break down sufficiently to raise pH).

[mtbigfish]

I have used white pumice instead of perlite for many years

[jackdaniel]

I am using Perlite right now, but have read good things about Vermiculite, so next time I will combine the two. Perlite is a bit larger, and is good for aeration. Vermiculite is smaller and blends in better, but is shiny. I can't see such small particles holding much water, though, unless you use a lot of it. Perlite does not hold much in my opinion. I am trying ProMix BX also. Got some Coconut Coir as well. Sounds like time for an experiment!

[mtbigfish]

jackd
there are variou grades of both perlite and vermiculite from fine (plug grade) to course planting grade

in my plugs I use pro-mix pgx plug grade perilite or pro-mix bx which uses both perlite and vermiculite - I use those with biofungacide

The two have completely different purposes as perlite is for aeration and drainage whereas vermiculite is for maintaining moisture content

both are for seedling and potting up of plants and bx works in containers though I add white pumice
I do not recommend for planting in the ground as it's too costly - I make up my own mix for that spagum peat, pumice, vermiculite garden and bloom vegetable mulch and more

Dennis