Perlite and beyond: the pros and cons of various drainage and aeration amendments

mad librettist · Jan 30, 2011

Perlite, chicken grit, sharp sand, builder's sand, vermiculite, turface, pumice, horticultural charcoal, axis, playball, napa 8822, charred rice hulls, lions, tigers,

OH MY!

It used to be those in the know were on the watch for good chunky perlite, because the fine crap from many stores did not perform nearly as well. The more traditional types stuck with less porous components like sharp sand.

Now, the choice of drainage/aeration components for container mixes has been expanded to include much more sophisticated materials that can provide enhanced durability, porosity, and some other qualities I hope we will read about in this thread.

My sense is that if you understand your "drainage" component and how it works, you are better prepared for whatever comes your way. It also lets you experiment. For instance, I just learned that in order to be effective, the particles have to be a large enough % of your mix so that they bump up against each other.

I don't claim to be one who knows, so I hope we hear from those who do. My 2 cents: calcined DE rocks!

DARC MIND · Jan 30, 2011

constructive criticism

constructive criticism

soil texture is a art imo
following foot steps is i guess a good start but thers more then one way to skin this kat

a "soil for beginners" thread imho will help much more people then a popular container soil texture enhancement thread.many many variables, understanding & good soil stewardship will turn dirt to a rich living diverse system.

Good soil management is better achieved through education and understanding than with blanket recommendations_building better soil for better crops

heres some links on the basics
Introduction to Soils
soils

mad librettist · Jan 30, 2011

a "soil for beginners" thread imho will help much more people then a popular container soil texture enhancement thread

that's not really criticism, that's pointing out the way of thinking already long established here. I'm after a different approach, not to compare how many people get helped, but to reach those who think the way I do - that is, the different components of my soil serve functions, and in order to be able to adapt intuitively to one's circumstances, one needs to play these functions against each other. It's easier to understand each function if it is observed, qualified, and deconstructed in isolation, theoretically if not practically.

I'm not sure I understand your point.

Glodenglow1 · Jan 30, 2011

For instance, I just learned that in order to be effective, the particles have to be a large enough % of your mix so that they bump up against each other.

That is an interesting tid bit that I did not know, makes sense from and aeration/porosity perspective

Batboy · Jan 30, 2011

mad librettist said:
My 2 cents: calcined DE rocks!

I've been hearing good things about calcined DE. I've started to incorporate powdered DE to fight fungas gnats, but I haven't been able to find calcined DE. Where do you find the stuff?

mad librettist · Jan 30, 2011

Batboy said:
I've been hearing good things about calcined DE. I've started to incorporate powdered DE to fight fungas gnats, but I haven't been able to find calcined DE. Where do you find the stuff?

All the good stuff I know of ultimately comes from Eagle Picher and is made from freshwater diatomite.

There are the turf amendments Axis and Playball, and there are absorbent products like Napa floor dri #8822. The difference is particle size and consistency, with the Playball apparently the best.

I have been using Napa 8822, with the fines screened out using my finest sieve. I love it so far. There is some sweat involved in the preparation.

Scrappy4 · Jan 30, 2011

First things first, what's wrong with large chunk perlite? Scrappy

Smoking Gun · Jan 30, 2011

While I usually use soils that already contain perlite, I still add more to my mixes. Whatever soil I use I mix at two parts soil to one part perlite, with a chunky perlite. My drainage has always been quite good, and my root growth gets rather explosive when switched over to flowering cycle. I also like to use a layer of red Lava Rock at the bottom of my pots; adds just a bit of insurance on my drainage.

mad librettist · Jan 30, 2011

First things first, what's wrong with large chunk perlite? Scrappy

This is what I have come across. Maybe someone can pick through this list for the true ones:

1)it floats
2)it is not as porous as other amendments and those pores get clogged.
3)it is short lived. After a couple "uses" it gets all clogged up, and it also breaks.
4)Fluoride
5)does not support as much microbial activity as well as calcined clay or DE
6)does not hold air as well as others
7)does not hold water as well as others
8)does not give up its water as easily as others

I also like to use a layer of red Lava Rock at the bottom of my pots; adds just a bit of insurance on my drainage.

All you are insuring with the lava rock is decreased root space. And your perched water table will still be active, only now it is even higher up your container. Maybe your roots could be exploding earlier? Try a wick next time, and if your roots are more vigorous earlier, you know I was right. If it's the same, you were right, and no harm done. But it's been studied ad nauseam, and everyone concluded the same thing: your mix should be the same throughout, without a "drainage layer".

DARC MIND · Jan 30, 2011

mad librettist said:
I'm not sure I understand your point.

just hoping this doesnt complicate something thats pretty simple
drainage and aeration
perlite,composted woodchips,char,pumice have all worked very well for me. clearly thought out soil,in design and a grower dedicated to guiding microbes for lush growth does alot.

simple good water management & mulching, will prevent water stress on your plants & keep your perlite (if thats what ur using) from rising to the top.
lots and lots of things can be used to help ur soil texture;my 2cents is use a diversity of paticle size,ratio depends on the feel. :ying:

mad librettist · Jan 30, 2011

just hoping this doesnt complicate something thats pretty simple

you sir, are no fun.
:moon:

jaykush · Jan 30, 2011

my 2cents is use a diversity of particle size

all im going to say is i agree with this.

SilverSurfer_OG · Jan 30, 2011

I like a decent amount of coco, perlite and a small % charcoal.

Sand always just seems to clog my mixes up and makes them very heavy. But thats more in pots.

There is a world of difference between various pots and straight in the earth or in beds.

:2cents:

compost · Jan 31, 2011

Good thread I am currently trying to find something to replace perlite in my mix. I have switched out about 50% of it with vermiculite but want something larger for the other 50%. I always like perlite but since I add my soil to my veggie garden I don't want the security risk when the perlite starts to float away.

mad librettist · Jan 31, 2011

well the DE products or turface might be nice in the garden, or spots in the yard where water pools.

VerdantGreen · Jan 31, 2011

this is the calcined / molar clay product that i've found in the UK. seems to be the right stuff?

http://www.serpro.eu/shop1/Safety-Tread-Granules-Pallet.html

Stankie · Jan 31, 2011

I was unaware perlite contained so much fluoride. I may have to reconsider its use.

danks · Jan 31, 2011

can charcoal from carbon filter be used ? is it better to use before running thru filter or after and at what ratio. is there any prep to it or just mix in. and can you use it with promix? and do you have to cut back on any fertilizer as charcoal has some k in it.

wisco61 · Jan 31, 2011

I just picked up some Carquest Auto part #7240. Its labeled Automative Oil Absorbent, 100% Fuller's Earth. I believe this is the same as Turface. It states it made up of amorphous montmorillonite clay and crystalline silica in varying amounts. Cristobalite is listed as the silica source. On the front of the package it actually lists "potting soil additive" as one of the uses which is good I guess.

It seems Carquest also has a DE oil absorbent, part #8033 that supposedly has less fines than the Napa 8822.

http://grow.lot-o-nothin.com/contai...arquest-premium-automotive-oil-absorbant-8033

My question is what size sieve is good for sifting this product? I have a kitchen sieve with holes about 1/16" that I sifted some of the 7240 I bought. Does this look like about the right size?

Before and after pic included.

wisco61 · Jan 31, 2011

mad librettist said:
For instance, I just learned that in order to be effective, the particles have to be a large enough % of your mix so that they bump up against each other.

I encountered this a couple days ago when I was reading about chicken grit.

BTW, check out cacti, bonsai, and orchid forums for discussions about these kinds of amendments. They seem to take them pretty seriously and they are growing plants over years so durability and non floatiness are important to them also.

Anyways, I understood it to mean that in non porous amendments like the chicken grit it was important for the pieces to touch each other. They don't have any natural porosity so their irregular surfaces do no good unless they are touching something else like that as the space in between is where the aeration occurs. But with something like pumice, DE, or even perlite to a degree they have a natural porosity so they can function isolated in the soil mix.

So for things like grit, pea gravel, etc its important to have enough in there, but not so much with other things. Am I off base here or does this sound right?

Perlite and beyond: the pros and cons of various drainage and aeration amendments

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