Is sand, basalt gravel or perlite better?

[richardhole]

Hello

Does it make much difference what I mix with the peat moss for carnivorous plants? I heard that washed quartz river sand or silica sand is good. However, the sand here for sale is probably mainly granite based which I heard has minerals in it and could be bad for carnivorous plants. I heard that it is mined from a quarry. Another option is crusher dust that comes from basalt and is used on out local roads. I was advised to use Quincan gravel if it is well washed. This is a porous volcanic rock. I heard that perlite is probably the best. However, I was a bit concerned about perlite after buying some once and reading the label that said it could be a health hazard if breathed in or handled. However, a web search tonight indicates no reported health hazards and that it is “used as filter aids in food processing” . See www.schundler.com/perlitehealth.htm and search Google for ‘perlite health risks’.
I am not sure if there are different types of Perlite where some types are more hazardous than others. Could that be the case?

Whatever material I use, I planned to wash it well by putting it on a fly screen and hosing it well to remove the fine particles and any dirt. I am not sure if this would be necessary if I used perlite or if I could just wet it??

Have you found any problems with any of the above gravel or sand?

Your help is appreciated
Regards Richard.

[Michael]

Forgive me if this seems like a silly/obvious question or answer, but doesn't it depend on how much drainage you want/need for a specific plant?

Mike

[richardhole]

Hi

I am referring to Sarracenia, Drosera and Venus fly traps. I know Nepenthes need more drainage and I am using half sphagnum moss and half Coir for them.

Currently I am trying one part Perlite and two parts sphagnum based peat for my Sarracenia, Drosera and Venus fly traps. If you know of anything else that is as good a mix, please let me know.

Your help is appreciated
Regards Richard.

[twigss]

I personally use sand and peat in a 1:1 mix in all my outdoor plants. Perlite would probably work the same or might even be better than sand for drainage but I refuse to use it outdoors. The first time it rains hard you will find that perlite floats and will completely cover the top of your pot. This doesn't really affect the plant but it makes the pot look terrible.

Recently I have given perlite a 2nd chance (only for my indoor plants). I have been layering the media for my my Cephalotus. The bottom 1/2 to 2/3rds is a mix of 1:1:1 peat:perlite:sand, on top of that is a 1:1 mix of peat and sand and I use pure sand as a top covering. This spring I might try this layering technique with some of my outdoor plants but I will keep the perlite layer well below the halfway mark of each pot.

The main benefits I see in using perlite are that it is much lighter than sand and it is cheaper per cu. ft.

[lordpyro]

We are using sand out of neccessity. Our local garden center doesn't currently carry perlite

[w03]

It depends on how much drainage you want, what plants you grow, and how much you water. Gravel and rock tend to be higher pH, and are best suited for mexican pinguicula that appreciate the high pH. Perlite and sand are usual components of soil that can be used for most purposes (although there are better substitutes at times). Sand usually gives less drainage than perlite, and both are fairly inert (if you are using silica sand). I have heard that perlite may contain mineral contaminants, but many people I know have used it without consequence.

As for health concerns, perlite does have fine dust particles that can cause disease. (Silicosis) However, silica sand has these particles as well, and I wouldn't be surprised if gravel contained such dust. It is not particularly hazardous, and probably at the same level as cigarette smoke. I wouldn't be too concerned. Having good ventilation when handling perlite and silica sand is enough of a preventive measure.

[spinnermaltese]

I voted perlite for the simple reason that it is a porous material, with a high content of oxygen needed by the roots, neutral pH (can be compensated by acidic pH water), Has a reasonable water holding capacity and light weight. Even under immersed conditions perlite can still provide reasonable amounts of Oxygen to the rooting system. For such reasons I am experimenting with perlite as a medium for carnivorous plants. I am mainly trying out a plantlet of Drosera with this medium using rainwater of course, in a drainless pot.

[Aidan]

Jan 3, 2011 15:28:42 GMT spinnermaltese said:

...with a high content of oxygen needed by the roots,

Useful for Pelargoniums perhaps but really rather irrelevant for most carnivorous plants, which originate from poorly oxygenated bogs and hence have root systems well adapted to anoxic conditions.

Perlite is not the miracle substance it is often made out to be and I for one, never make use of it.

[Joseph Clemens]

Perlite is nice. Silica sand is good. But basalt gravel is, what? I've never heard of its use in CP culture, before. I researched where I could obtain some - but have not yet located a source. If I find some, I'll give it a try.

A few decades ago I had a source of small white quartz gravel. It was delightful as a top dressing - I miss it. It helped suppress moss and algae, and looked nice.

[kulamauiman]

Aloha Joseph,

it is probably the most common non-coral sand that I can find here in Hawaii. It is a fairly dense, blue, rock, of igneous nature. May add some nutrients (minor elements, K, etc) but only in really trace amounts. i contemplated using it when I started growing CPs. It is a bit less expensive than the play sand that i am using. Never really tested it ........