Which do you choose to make your hypertufa? Vermiculite or Perlite? What is the difference to your hypertufa project? So many questions and I am exploring to see if I can offer some explanations from my point of view. Imagine my surprise when I found out there were so many vermiculite uses? Who knew?
Vermiculite uses in Hypertufa Making
First of all, I like to use vermiculite for my aggregate to mix with the Portland cement when I make the hypertufa. It is a brown color and I like the blending into the colors of the hypertufa that I am making. It seems to have a glittery sheen to it and I like that. Though it is a very light material, I think my pieces may be just a little heavier using vermiculite instead of perlite.
Vermiculite is the name given to a group of hydrated laminar minerals (aluminum-iron magnesium silicates) that look like mica. So what is mica? It is a shiny silicate mineral with a layered structure, found as minute scales in granite and other rocks, or as crystals. So now I at least know why I prefer that look in my hypertufa projects. I like that vermiculite gives that sparkle that some real rocks have. I know, right?
I was surprised at so many vermiculite uses. Construction, automotive, packaging, swimming pool liners, etc. Unlike the hard perlite, it is a soft material and spongy too. In my video you can see my fingers just smush it like a sponge. This illustrates its moisture-holding quality. Both vermiculite and perlite are inorganic products and are very light-weight.
How is Perlite Different?
Perlite is a white porous material, slightly crunchy, and it is made by heating volcanic glass. When you super heat the glass at about 1600°F, it pops like popcorn and makes that little fluff of “stone” that looks like someone crumbled up some Styrofoam. It is also used to aerate the soil, assisting in drainage, and also traps air in those little crystal caverns helping to keep plant roots alive and healthy. Healthy root = healthy plant, right?
Just like vermiculite, perlite is used in construction, insulation, plaster, ceramics, hydroponics, cryogenics. It is even used to filter beer before it is bottled. But we use it in our gardens and this is the main use of perlite. We hypertufa makers use it as our aggregate in hypertufa. It shows sometimes as small white bits embedded in the hypertufa. It doesn’t look bad, I just prefer the darker vermiculite for myself.
Vermiculite and Perlite for Seed Germination
In seed germination, it is great to use either of these materials. It is a relatively sterile mix as opposed to some soils which could contain molds or other contaminates. (Read: GNAT larva. Been there, done that.) So it is a great medium to use for seeds, cuttings, pups, whatever you are needing to root or propagate.
Vermiculite holds moisture for longer periods and can hold more water than perlite. So it is great for starting seeds that you would want to keep evenly moist without having to constantly watch for dryness several times a day.
Perlite is great for cuttings since it traps water on its surface area, in the nooks and crannies of that little puffed stone. It releases water quickly. It seems that cuttings would be less likely to rot. Sounds perfect for our succulents and cacti. I will have to test this out myself. I have my cuttings lying on top of soil and a layer of sand, so I will try one with perlite and see what happens.
Vermiculite and Perlite for Soil Additives in Containers
Based on that information above, I would think that a gardener would need to determine his or her needs based on where he is gardening. If I am in a hot and humid environment, I might choose the moisture-retaining vermiculite as my soil additive. However here in Ohio, I think the perlite is better for me in my rainy spring, summer, and fall days. So each location should determine which is better for you.
Also I need to mention, I used to find it difficult to find vermiculite. All that was carried at the local stores here was Perlite. Now these days, I am finding just the opposite. It is easier to find vermiculite than perlite. I have no idea why.
I get my vermiculite online in huge bags that fill a 32 gallon garbage can. That is the easiest for me. Those small bags I find at Lowe’s only last a few bowls. I can include my affiliate link here if you need to order and have it shipped in a large quantity.
Handle Vermiculite and Perlite with Care
Be careful not to inhale dust from these materials especially if you have lung problems. The same goes for peat moss, soil, and all of the materials we gardeners use. Don’t let this stuff be so dry that it raises airborne particles to get into your lungs. It is always best to moisten it with a mister/hose before use and put that face mask on!
Vermiculite from some mines in Montana was found years ago to contain asbestos and that vermiculite was used in some homes as insulation and caused many medical problems such as asbestosis and mesothelioma, a deadly and aggressive cancer of the pleura. Those mines were shut down and a clean up progressed. But many homes, gardens, etc used the contaminated material. You probably are aware about warnings regarding disturbing older homes when you remodel and the possibility of running into Asbestos and having a major and expensive clean-up.
I felt I needed to mention this in my post so that anyone who has lung problems might use extra caution. Just as we use care with our Portland cement, we need to use care with the potting mixes and other ingredients too.
I am so sorry I have gone to the dark side in this post, but I need to disclose those things that I have read and heard so that you are as informed as I am able to offer to you. Always exercise caution in what you do in the garden and handle everything as labeled. Read those cautions on the sides of the bags and heed those warnings.
Hi, I am Kim and thank you so much for visiting my magazine! I am a gardener and a hypertufa maker. If you came here to learn about hypertufa, I have a lot of information. But I also write about flower gardening and using succulents which are great drought-tolerant plants.