vermiculite vs perlite

[Noah Yates]

what different things do they do? they are both aerators. one is far more suitable for seedlings than the other. neither hold an appreciable amount of water, so neither are suited for such a task imo.

i think you will find that you are alone in your assertion that they differ vastly and accomplish very different things within any soil mix. like i said, a good chunky verm will not hold much water whem compared to an equal volume of say coir or peat or the like. super fine verm probably holds more, as the same is true with fine perlite.

if you are adding verm to a mix to add water retention... imo you are doing it wrong. add a small volume of peat/coir or compost to your liking , then fluff it out with either aerator to your liking.

also i dont see how using them both accomplishes anything either or could not.

lol... word?! I think among people who know what they are talking about you will find yourself alone in this assertion. If you think perlite and vermiculite are essentially the same then you are mistaken. Vermiculite is used in mycology as the* water retaining substrate amendment of choice. The way the two hold water is completely different too. Vermiculite imbibes water within* its "cells," while perlite retains water be adhesion to its vast surface area. Also, vermiculite, unlike perlite is actually nutritve--providing a whole range of trace minerals and micro nutrients to both the plants themselves and the beneficial fungi and bacteria in your soil. I would never argue that vermiculite or perlite are the* water reatianing elements of a soil composition. In fact, that is what I was aluding to with the assertion that a better topic for comparison would be that of the pros and cons of using cococoir or peat moss... as peat moss retains too* much water, while cococoir holds just enough and dries out readily--making the soil less prone to water logging. Also, although both of these base amandments are known for their drop in pH over-time, peat is known to become acidic much more quickly than coco coir. This along with the consideration that, unlike peat moss, cococoir is renewable makes for a great argument for why coco coir could or should* be used exclusively in a mix. Vermiculite and perlite are so vastly different that they should always be used together. However, peat moss and cococoir are so close to each other that you could choose to use one exclusively depending on the needs of a given plant... If you want a soil that never dries out and is slightly acidic then use peat (tropical plants fit this category (bromeliads and such)... while if your plants prefer not to have wet feet and want more neutral pH then coco coir is the better option. But to say that verm and perlite accomplish the same end in a mix is incorrect.

Edit: I found this link which does a pretty good job of elaborating on the differences between the two amendments, perlite and verm.
http://worldseedsupply.org/blog/?p=113

 

[Balduvian]

thank you everyone, im pretty sure i know what ratio ill be using them. ill be using both vermiculite and perlite

 

[queequeg152]

i don't think i argued that they were essentially the same, only that they accomplish basically the same thing, and that is to aerate a mix. im aware of the finer points of their physical properties as well as their use in growing mushrooms. i seriously considered growing edible mushrooms at one point, but gave it up as other things occupied my time. i even have a very expensive 6" thick hepa filter with neat little pleated aluminum foils for a laminar flow hood that was never built.
what i disagreed with,was your assertion that it was that they accomplish substantially different things. yes verm holds water better than perlite. however one is not adding verm to increase the water holding capacity of a mix. this is what i guess i had assumed you were asserting.

to clarify i would assert that a comb and a brush accomplish the same thing.i suppose one could argue that one is substantially different from the other. im guessing this is the avenue this conversation took.

also im wary of your claim that verm is nuitritive in any substantial way. exfoliated verm is just crammed full of metal oxides. while is is true some metals can be metabolized by exotic critters, i fail to see how they could substantially add to the mixes available nutrients.

also it should be noted that coco coir while being suitable for replacing peat in many crops like toms and peppers and cuces, it is not entirely compatable with many others. there's a number of papers that show how it under performs when compared to peat lite mixes with respect to several ornamental crops. coir is relatively new to the scene and as such has not been studied as well as it probably should be. on the other hand, coirs been used in commercial hydroponic/fertigation greenhouses for decades, and its proven to be especially efficacious, performing on par with rock wool. in my area here in houston, peat is fairly hard to get. the peat we have available is pretty much all sedge, spagnum is very rare, when you can find it its about 5 bucks a bail more than sedge up to around 30 bucks a bail. at this price its pretty much cost prohibitive considering i can buy 4 cubic foot of expanded coir for about 18 bucks. im probably going to switch to a coco lite setup next year for this very reason. peat keeps going up an up where as coir seems to be coming down consistently.
im not going to miss adding the lime/ surfactant charge tbh, this gets old after about 20 cu ft.

 

[Noah Yates]

Yeah the rising cost of peat could very well be correlated with its being non-renewable, and therefore rapidly dwindling in supply. Vermiculite is nutritive though. Its not going to provide anything close to all the nutrients required for healthy growth... but I thought i would mention that it is nutritive in a thorough discussion on the diff between verm and perlite. And congratz on your flow hood. Those are an amateur mycologist's dream tool. If you ever do get into mycology that will be like owning a Ferrari.

 

[georgej]

having asked a similar question a while ago. i since used both and much prefer Vermiculite.

Make sure you wear a mask when handling it though. i learned the hard way that it hurts like hell when it lodges in your sinuses. its super dusty and is easily inhaled

 

[Balduvian]

ya from everything ive read and peoples opinions im using a combo of perlite and vermiculite.
while its a smaller plant im gunna use 3:1 ratio vermiculite to perlite
once i plant them in their final pots im going to use 3:1 ratio perlite to vermiculite

thanks all for the help

 

[Noah Yates]

Sounds pro!
 
 
 
 
-ductive!!!

 

[PHB]

[...] yes verm holds water better than perlite. [...]

 
Didn't you mean the inverse ? I always thought verm has a water retention of 40-50% and perlite of 500% ??
 
Not saying it does (I've very basic knowledge of those substrate), just need infirmation or confirmation from those who do know.

 

[Balduvian]

Didn't you mean the inverse ? I always thought verm has a water retention of 40-50% and perlite of 500% ??
 
Not saying it does (I've very basic knowledge of those substrate), just need infirmation or confirmation from those who do know.

i've done a lot of reading, vermiculite holds water much better then perlite actually, perlite can absorb up to 500% of its own mass but it doesnt retain the water like vermiculite does, it drains the water out much quicker.

but you are right it will hold more water than vermiculite but not by much. vermiculite is about 400%, but it will hold that water a lot longer than perlite will