Vermiculite vs perlite

Perris, CA(Zone 9a)

What is your favorite soil mix to start cuttings in? I have seen them with vermiculite and I have seen them with perlite. Occasionally I have seen them with both. By the way, I have learned the hard way not to start cuttings in plain soil and without root hormone.

So sorry, forgot about the question. What is the difference between perlite and vermiculite?



This message was edited Dec 7, 2008 8:44 AM

(Lynn) Omaha, NE(Zone 5a)

I like half perlite,half peat moss.One difference between them is that perlite helps improve drainage and vermiculite,when used as a soil additive,helps retain soil moisture.Both are useful for changing soil texture.

Kingston, OK(Zone 7a)

Vermiculite is softer then perlite and will compact some what. It has more nutrients then Perlite. Perlite has none and is hard.
Perlite will float and does not blend well with the soil. Both retain a lot of moisture and improve drainage. I use both in a soil mixture.
Three parts peat, two parts Perlilte and one part Vermiculite. Add slow release fertilizer and a little lime.

Perris, CA(Zone 9a)

Thanks, both of you!!

Merry Christmas,

Thanks again,


Poughkeepsie, NY(Zone 6a)

Perlite is my choice. Light weight and adds MUCH aeriation to the mix. I don't use or need Vermiculite.

Bluffton, SC(Zone 9a)

I vote vermiculite.

Tulsa, OK(Zone 6b)

I prefer perlite. both are excelent addatives. perilite has the negative side of effecting plants with a low tolerance to florides. Draceana genus specifically.

Johns Island, SC

I use them both, but more perlite than vermiculite, although I've never done a cross-plot controlled experiment to really determine the differences. Just seems to me that vermiculite retains more water for a longer time than perlite (no science here, just observation!), I use a perlite mix for most routine plantings. If I'm planting seedlings that need a lot of water, I'll mix in vermiculite, but most prefer the high perlite mix. Happy with results so far...nothing takes the place of attentiveness!

Tulsa, OK(Zone 6b)

SR: you are so right about being attentive. The monster can run you over if it getts loose...LOL

Marysville, WA(Zone 8a)

It was mentioned above that vermiculite will compact. This is why when you look for in commercial mixes, you'll probably only find it in seed-starting mixes. We don't use those long enough to have serious side effects from a drastic change in water needs & compacting. It really looses it's good drainage/oxygen-carrying capacity as it ages.
So vermiculite is a very poor additive for any permanent mix. You can get the same water-retention effects by just changing your ratio of peat-to-perlite, or use other water-retention ingredients like a little coir in the mix. :^)
- Tom

Johns Island, SC

I know all too well,Pughbear! The monster got loose in my GH the first year I had it and really taught me something. Especially about white fly, spider mites, and overwatering. The monster definately won that 1st round, but I've stomped him flat since then. He doesn't even show up around here anymore...

Taft, TX(Zone 9a)

I was using mainly 1/2 perlite and 1/2 peat moss (or any soil less mix) until someone told me the benefits of the vermiculite changing the ph in the now I use 1/4 peat moss, 1/2 perlite and 1/4 vermiculite on everything.........gesneriads to great.

Presque Isle, MI(Zone 5a)

I read about a guy using 1/2 perlite and 1/2 kitty litter.


Poughkeepsie, NY(Zone 6a)

Gary "Turface" can also be used. It's the stuff used on baseball fields.

This message was edited Dec 28, 2008 2:20 PM

Kingston, OK(Zone 7a)

garyt I have been the route of kitty litter.
Wall Mart red bag stuff is what everyone was talking about.
It is not the same as Turface as it is not fired high enough.
More like vermiculite soft.
You have to screen out all the dust as it will make gunk.
Turface is an excellent product.

Central, TX(Zone 8b)

I use half & half (medium sized particles) for most cuttings where slight moisture and good drainage is required. I use a thin layer of fine vermiculite to cover the surface of seeded flats. Perform a Google search to find the qualities of each. Use a dust mask when handing this material, you don't want to get it into your lungs. When mixing batches I use to a separate plastic tub, mist the material with water then stir to mix before filling my containers. Use a seedling "fog it" nozzle (1/2 gal/minute).

Tip - Purchase fresh potting materials each season and be sure to seal the bag to keep it dry and store it in a closed container to keep contaminates from spoiling your investment. If moisture or critters have invaded your propagation materials, pitch and purchase fresh!

Happy Gardening,


Perris, CA(Zone 9a)

Thanks, Buster!!

I have never heard about tossing last year's vermiculite and perlite. I am pretty sure I am going to have to do this. Thanks to everybody for your comments. I have learned a lot.

Thanks again,


(Sheryl) Gainesboro, TN(Zone 6b)

I'm afraid I don't throw away much. I sterilize everything I use for starting cuttings or seeds in the microwave and will mix old stuff with new, fresh stuff or send it to the compost pile, or if it doesn't have anything nasty in it, I'll put it in my outside beds. I'm not sure why moisture would be a problem unless it was allowed to mold or get bugs or something, and even then, it will be fine in a hot compost pile to become new soil again.

Presque Isle, MI(Zone 5a)

Can I use bleach to sterilize the rooting media instead of putting it in the micro wave?


Poughkeepsie, NY(Zone 6a)

I wouldn't.

Casper, WY(Zone 4a)

I use a mix half and half of perlite and peatmosss for rooting cuttings. I never sterilize since there is no need for it. It produces a very airy and light mix for roots to grow in.

Perris, CA(Zone 9a)


Do you use the same for seedlings? I am trying a new way for salvia seedlings that are annuals. I waited until the peat pots each have four adult leaves each (no cotyledons). Then I transplated them in 1/2 potting soil and 1/4 each of peat moss and vermiculite. So good.

I will tell you what happens.



Casper, WY(Zone 4a)

Yes you can but you can also replace the perlite with vermiculite. In either case, the mix does not contain any nutrients for the plants to grow in so you would have to add a liquid or slow release plant food. Personally I prefer the perlite since it gives excellent drainage and light mix. Vermiculite tends to pack down with time.

Actually, you can also use Miracle-grow potting soil. I use it for all my houseplants and it will do nicely for seedlings also.

Why did you add peatmoss and vermiculite to the potting soil? Unless you bought cheap potting soil it isn't needed. Miracle-Grow is great and does have nutrients. It is not soil but artificial. Use as is straight from the bag. However it needs to be moistened first before using.

Everett, WA(Zone 8a)

It seems to me that even coarse vermiculite crumbles really easily, so it doesn't keep a mix "open" for long.

Perlite is hard enough that it lasts, and helps increase drainage and aeration, but it's so light that it will float to the surface after watering too hard.

I like screened, washed grit like chicken grit (crushed grantite, not seashells). It is hard enough to last forever. However, #2 chicken grit is a little bit finer than I would like (like 1-2 mm).

Double-screened, washed, crushed rock might be good but it was expensiv e and I would have had to buy a cubic yard and paid for delivery!

Now I buy clean pine bark mulch (medium) or small bark nuggets and screen it to remove big chunks and remove dust and fines. Depending on how many fines you have left in the gritty stuff I use to replace Perlite, I may add 30% bark nuggets to a peaty commercial mix, or add 10-30% peaty mix to 70% bark.

Bark holds much less water than vermiculite or peat.
Depending on whether you have just nuggets or some fine fibers and dust, bark holds different amounts of water and air. Always more water than Perlite but less than peat.

Sprinkling bark nuggets on top of a container assures a dry surface to defeat algae, fungus gnats and damping off. Water runs right through it, and it dries quickly. Like light-weight, coarse grit.

Casper, WY(Zone 4a)

I still prefer 1 part peatmoss to 1 part perlite for cuttings.

(Lynn) Omaha, NE(Zone 5a)

Sometimes when I use bark in my mix certain plants don't seem to like it.Maybe that is just my experience??

Everett, WA(Zone 8a)

>> certain plants don't seem to like it.

My first assumption is that you're right. My own experience is mostly with one of two things:
1. overwatering nearly pure peat during my first year or two starting seeds, or else
2. mixes with bark and more experience

So, to me, bark helped everything I noticed. But that is definitely only MY biased experience!

I can say that I killed one whole tray olf petunia seeds by "surface sowing" them "on top of" a much-too-coarse bark mix. Don't do that! Either petunia seeds hate bark, or the tiny seeds fell into deep crevices between bark chunks and never got the light they seeded. Or they sprouted down there and could not push their way back to the surface. Or both.

I have noticed that the local Steubers nursery & farm supply place has many peat-based mixes and peat moss, but NO BARK. The clerk's tone was like "We don't sell BARK, YOU DUMMY, we know what we're doing!" Or maybe he thought decorative bark was only for Yuppie dilettantes.

I do see that books and online forums mostly say "peat or sphagnum moss plus Perlite and vermiculite". Tom Clothier (whom I respect greatly) uses grit for some things but I don't think he mentions bark.

I have read in more recent sources that bark fibers or fines can be substituted for peat, as a sustainable alternative, but they don't sound very enthusiastic. Also, modern potting mixes use "some" bark fibers in their mix.

I got the idea of pine bark nuggets and fines from Al (Tapla), whom I also admire greatly. He uses it in a gritty mixture intended to last for a long time in containers, for potted plants. I don 't recall him advising it for seed starting.

What I'm sure of is that it is better than over-watering so much that you drown all the roots! I guess most gardeners learn to avoid over-watering.

I'm also sure that it's a cheap alternative to Perlite if you do your own screening and de-dusting.

(Lynn) Omaha, NE(Zone 5a)

Thanks for the info Rick.I grow Gesneriads and many of my fellow growers swear by the mixes with bark in them.I used to use it,but it seemed like Streptocarpus and Primulina didn't like it.I am sure there are many kinds of bark out there and I may have picked the wrong one.

I agree,anything is better than over-watering! I am all for the cheap part too.

Everett, WA(Zone 8a)

Al (Tapla) was looking for a long-lasting ingredient, so he leans towards PINE bark and some other confers (fir & hemlock). Those have a waxy component (suberin) that resists decomposition and is water-repellent.

Compared to peat moss, pine bark holds much less water. If Streptocarpus and Primulina like damp roots, or their root hairs want FINE fibers, bark might not be to their taste.

Orchids, on the other hand, love bark. But bags of "orchid bark" are priced like shredded $5 bills!

(Lynn) Omaha, NE(Zone 5a)

The roots are pretty fine and they require a light mix with good drainage.

Everett, WA(Zone 8a)

>> The roots are pretty fine and they require a light mix

I bet they didn't like the chunky nature of most bark products. I think that beating or c rushing bark, then shredding it finely, would give fibers more like peat ... but that's a lot of work.

>> with good drainage

That part of it, bark could handle better than peat.

(Lynn) Omaha, NE(Zone 5a)

Thanks Rick.I may try it with shredded bark.

Ottawa, KS(Zone 5b)

Perlite retains air. Vermiculite retains water. I add Perlite to my growing mix to aerate it and sometimes I sprinkle fine Vermiculite over my seeds to cover them (in lieu of using the more expensive, but possibly better, milled Sphagnum moss). I haven't found a good local source for bark nuggets. They would be good in large pots for larger plants, where water logging and root rot are a real possibility.

It would be great if the same process used to make puffed wheat out of wheat grains could be adapted to make puffed bark nuggets. Shot from guns?? (grin) I'm not going to be trying to think of a clever name for the product, though.


Everett, WA(Zone 8a)

Now the 1812 Overture is running through my head.

>> I haven't found a good local source for bark nuggets.

Yeah! I looked for quite a while, and the best source went out of business. Several sources have suggested that, since most of the expense of bark products is shipping, the actual contents of mixes vary regionally even if one company uses the same name for different mixes.

Maybe not for the more reputable ones like Pro Mix BX.

Here is what I found in Western WA / Seattle area:
- Home Depot: filthy dirty, soggy, fermenting "mulch" that;'s more like logyard waste. Cheap but not worth it.

- local "dirt yards" - bark mulch - cleaner than HD but still somewhat dirty. Needed to screen it. Lots of fines and shreds, but some dirt. Maybe weed seeds? I don't know. I only use this outdoors now.

- Lowes - $4.20 / 2 cubic feet pine nuggets: clean & dry. The Small size still needed to be screened, it had a little dust & some fines & some too-big chunks. This is what I use most of now.

- a local pricy nursery had $8 / 2 cu ft "beauty mulch" that was clean & dry & had beautiful shreds - but a lot of fines and dust so I never got rid of all the fines. They went out of business.

- double-screened Pine Bark Fines: online sources too pricey for me even BEFORE shipping!

- "Steubers Distributing" (nation-wide distributors to nurseries & farmers). Good selection of PROFESSION mixes. Mostly peaty mixes but more open than "Miracle-Gro". They don't seem to believe in bark.

Casper, WY(Zone 4a)

Actually, Jiffy makes a seed starting mix that I use for my Daylily seeds now planted in 6-packs after sprouting. Walmart sells.

If you sow other seeds in trays, you can use regular potting soil up to 1/2" to surface, then seed mix for the upper 1/2". Why waste the seeding mix since seeds will grow roots in the potting soil just as easily.

Ottawa, KS(Zone 5b)


Thanks for the tip on Lowes as a source for pine nuggets. Next time I am in there (our nearest Lowes is nearly 50 miles away) I will try to pick up a bag or two of them. When I first came to this area I couldn't find local ProMixBX and used an alternative product that a local greenhouse was using. The greenhouse management had had a "falling out" with the Premier ProMix distributor, and was buying in truckload quantities from the Fafard product line.

That greenhouse had everything from small seedlings to big trees for sale, and a lot of things in big containers on outdoor tables made of steel grillwork for total drainage. The majority of their plants were in relatively large containers that required a lot of good drainage, and they were using a Fafard product that was primarily bark (probably pine) with some additives, including possibly a little Vermiculite and Perlite and a minimal amount of sphagnum peat. I purchased a couple of bags of their "favorite" Fafard product, which was primarily bark based, with lots of bark chunks and pieces, and had great drainage. I had very good luck with it for larger indoor grown zinnias. But it was definitely not something that I liked for seed starting. It was so "open" that your experience with lost petunia seeds would have been replicated even for my much larger zinnia seeds. Fortunately I found a local source for Premier ProMix BX, which I still prefer for seed starting, but as you can see in the picture, I add a significant amount of extra Perlite to my ProMix. (The bin on the left is "ready to use".) When I re-pot my seedlings to larger pots, I use a lot higher percentage of coarse Perlite for increased drainage/aeration.

One advantage of bark over Perlite that you might not think about is weight. Perlite is very light weight, it picks up very little weight from water, and large plants in a high Perlite mix can actually topple over in the mix. Bark has the weight and "friction" to hold the plant steady, even in an outdoor windy setting.

(not associated with any product or vendor mentioned or linked)

Thumbnail by Zen_Man
Everett, WA(Zone 8a)

>> Perlite is very light weight, it picks up very little weight from water, and large plants in a high Perlite mix can actually topple over in the mix.

Yup, I distrust "weightless" mixes. But it makes it really easy to tell how dry a pot is! The ONLY weight comes from the remianing water. Crushed granite gives a mix lots of gravitas.

Also, I just dislike the appearance of "white styrofoam bubbles". When I dump used potting mix into a rasied bed outdoors, I think it makes the soil look like a "pot" grower's discarded hydroponic mix.

>> ... lots of bark chunks and pieces, ...
>> But it was definitely not something that I liked for seed starting. It was so "open" that your experience with lost petunia seeds would have been replicated even for my much larger zinnia seeds.

I always screen my "seed-start bark" finer than my "container bark". And I pick big chips or nuggets off the surface of each cell so sprouts don't have to push any "logs" aside as they emerge. But I set those along the edges of the cells so I can put them back on the surface after the seedlings are up. The big chunks stay dry, support the seedling, reduce evaporation, and deter damping off.

But sometimes I do make a top layer of extra-fine bark mix or Vermiculite, being careful that it mixes with and grades gradually into the coarser mix in the rest of the cell. I don't want the top 1/4" to be all perched waterlogged becuase the coarseness changes too abruptly!

I think you arfe right to guard against seeds "falling into canyons" in the seedbeed. The ancient gardening advice that a seedbed surface needs "fine tilth" is just plain right.

Thnaks for the tip about Fafard mixes! What I see in pots in nurseries seems to have more bark than p;eat, and I like that. I see many of Fafard's mixes are half peat or more, until you get to the heavyweight mixes.

But these look promising:
Ground Rules™ Pine Mini Nuggets

Ground Rules™ Pine Mulch
• Flower beds, pathways & play areas, trees & shrubs.

Ground Rules™ Pine Nuggets


Ahh! I like these, but I see they want to sell them by the truckload:

[b]Bulk Mixes from Eastern Canada - Standard Formulas[/b]

Nursery Mix (Product code MS-4003)
• 60% bark, grower peat & brown peat, perlite, Dolomitic
limestone & starter nutrients.

Bedding Plant Mix (Product code MS-4001)
• 30% bark, grower peat & brown peat, gypsum, perlite,
starter fertilizer, wetting agent & Dolomitic limestone.

Perennial Mix (Product code MS-4016)
• 38% bark, grower peat & brown peat, compost, perlite,
starter fertilizer & Dolomitic limestone.


(Not associated with anyone or anything!)

Johns Island, SC

The best seed starter medium I've found are those little "Park Start" plugs that fit into a styrofoam container which nestles into a hard plastic tray with a clear plastic cover. I put them on the heat mat set @70 degrees, and the magic happens. I don't know why, but seeds that need "light" for germination, "dark" for germination, high, medium, or low water for germination, all seem to take root in those things, and grow well. Once they get 4 true leaves, I move them to 4" pots filled with Pro-Mix plus a cup of Bolster per 10 feed scoops of Pro mix, and grow them out to transplant size. Have no idea why this seems to work so well with the variety of things I grow, but it does. Not a very scientific approach, I admit, but an expression I learned moving south 50 years ago applies here: "Hey, if it works, don't fix it!" Only disadvantage...Park's are real proud of their "Park Starts"...but in my experience, well worth it.

Provo, UT(Zone 5a)

here in utah we use to get the premier pro mix..lately seems
box stores have dropped it..and gone with miracle gro,other brands
which are "ok" i miss using pro mix..
fafard is a super local carriers..
one has fox farms..but they put alot of other stuff in..and i find best
sucess (starting seeds) with a light i add ALOT of perlite..
off this specific going to start using pumice in my amorph
pots.. ?? anyone else like pumice?? its heavier than perlite..but it doesnt
break down as perlite does over the summer..
looking foward to march..when i start my tomato seeds !!!! :)
tired of winter..LOL :)

CREZIERES, France(Zone 8a)

It seems to me that vermiculite (fine grade) is best for seeds and has the wonderful property of totally eliminating damping off without the need to spend time and energy in sterilising the compost.

My method is - for non-crevice plants - basic mix 1 part each peat, vermicompost, fine vermiculite, sand. On this I put ½" of fine vermiculite. Large, medium and fairly small seeds, I sow on this and cover with ½" grit. Very small seeds, I mix with 1 tsp finely sieved dry sand and cover the vermiculite with grit. Then I sprinkle the sand:seed mix over the grit and wash them down to the vermiculite with a fine spray.

For crevice plants, I add two parts grit to the above mix.

The grit has two uses: it slows, substantially the drying out of the compost, so an hour's fierce sunshine doesn't desiccate emerging seedlings, ans as the seedlings have to grow around the grit, they are better separated in the pot. The grit also allows light for photo-sensitive seeds.

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