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

SativaHybrid · Feb 1, 2011

Just to add some distinction between pumice and what im talking about, which is scoria.

"Scoria differs from pumice, another vesicular volcanic rock, in having larger vesicles and thicker vesicle walls, and hence is denser. The difference is probably the result of lower magma viscosity, allowing rapid volatile diffusion, bubble growth, coalescence, and bursting."

One of the only benefits i initially thought of was the fact that scoria doesn't float in water.

Muleskinner · Feb 1, 2011

great thread. I'm surprised DE is good. The bag of DE I have here for killing the centipedes that plague my basement is very fine-grain, almost like powder, I wouldn't have thought it would help with compaction like Perlite does.

in terms of Perlite floating to the surface I've had good luck using a local soil mix that has coarser peat and compost in it, it does a much better job of trapping the perlite.

When the quality local garden store loads up for spring in a couple months I will have to check it out & see if they have any of these newer alternatives like rice hulls, DE, etc, sounds awesome.

mad librettist · Feb 1, 2011

heady blunts said:
mad i know you've been loving the DE recently.

i'm a little unclear about all the benefits of it. as far as i understand, it retains moisture, adds porosity, lightens the soil, and adds calcium. am i missing anything?

is it possible to have too much calcium in a soil mix?

silicon! lots of it.

It supports lots o microbial life. But man does it ever drink! I have my cloning bed filled with it. SO imagine the difference if your soil can hold more water, air, nutrients, and microbes per tablespoon. That's what the DE does, at least compared to perlite.

I'm using it with carnivorous plants, so if it acts like lime they will probably die.

heady blunts · Feb 1, 2011

mad librettist said:
I have my cloning bed filled with it.

wait, you just stick fresh cuttings in a moistened bed of DE and they root?

at the sweet garden center i found yesterday they were selling berry cuttings that were rooting in what i now believe was probably DE. it was awesome! you just pull out big ass root balls with zero damage.

mad librettist · Feb 1, 2011

heady blunts said:
wait, you just stick fresh cuttings in a moistened bed of DE and they root?

I hope so!

jaykush · Feb 1, 2011

wait, you just stick fresh cuttings in a moistened bed of DE and they root?

I hope so!

i clone in it, but it wasn't 100% DE. it was DE and a small amount of EWC. id say 90% DE though. i actually have about 30 gooseberry cuttings in a similar mix with just a wee bit of char added as well as a wee bit of azomite. i like how the mix holds water like crazy, yet it drains like almost pure sand.

heady blunts · Feb 1, 2011

whoa that's awesome. i hate rock wool. do you water them with a kelp solution? or lower the pH with citric acid or anything else?

mad librettist · Feb 2, 2011

i have soluble seaweed powder... is it supposed to help?

heady blunts · Feb 2, 2011

well i asked about seaweed's effect on rooting a while back and it seemed to be the general consensus that it helps promote root growth. i had originally wondered because my seaweed extract has directions for rooting cuttings, and i know in general it helps with root health.

mad librettist · Feb 2, 2011

what is your usual application rate vs for rooting?

Clackamas Coot · Feb 2, 2011

heady blunts said:
well i asked about seaweed's effect on rooting a while back and it seemed to be the general consensus that it helps promote root growth. i had originally wondered because my seaweed extract has directions for rooting cuttings, and i know in general it helps with root health.

Seaweed in Agriculture and Horticulture by William Stephenson, founder of Maxicrop

"Auxins in seaweed include indolyl-acetic acid (IAA), discovered in seaweed in 1933 for the first time. Two new auxins, as yet unidentified, but unlike any of the known indolyl-acetic acid types, were also discovered in 1958 in the Laminaria and Ascophyllum seaweeds used for processing into dried seaweed meal and liquid extract. These auxins have been found to encourage the growth of more cells -- in which they differ from more familiar types of auxin which simply enlarge the cells without increasing their number. One of the auxins also stimulates growth in both stems and roots of plants, and in this differs from indolyl-acetic acid and its derivatives, which cause cells to elongate but not to divide. The balanced action of this seaweed auxin has not been found in any other auxin."

You'll note that IAA is a component found in many/most rooting products.

HTH

CC

heady blunts · Feb 2, 2011

well i've been top dressing with a dry mix actually, but when i was doing soil drenches i was using a pretty dilute solution like <1 oz per gal (they recommend 1.5-2oz/gal but i was using it more often than every 3-4 weeks).

for rooting the bottle recommends 5oz/gal solution to dip the cutting in before you set it in soil, but it would probably be too strong for wetting the rooting medium.

btw, from their site: "GROW MORE SEAWEED EXTRACT contains low concentration of naturally occuring plant growth auxins, gibberellins and cytokinins."

Thanks CC lol.

3gunpete · Feb 2, 2011

just a thought on perlite and its flouride content. All the food we eat produced domesticly or abroad are grown using heavy amounts of perlite, it is standard ag practice. And there have been no conclusive reports that im aware of about the transference of this from plant to use. And i would have to guess that the effects on your lungs is more from exposure to dust particles acting like cement when inhaled. It is always best to lightly wet perlite with sprayer before using. Any dust particles regardless of the source have detrimental attributtes to them no matter how natural they may be. (Just playing devils advocate here a little). That being said cant hurt to explore the least contaminate solution in are ever evolving world. Good quality coir, perlite, chunky wood chips, and lava rocks seem to compliment each other and work for many. I am definatly interested in the rice hulls thoe,

Thanks for the info everyone. Keep smiling!!

Clackamas Coot · Feb 2, 2011

3gunpete said:
All the food we eat produced domesticly or abroad are grown using heavy amounts of perlite, it is standard ag practice

It is?

Cost alone would make this idea a non-starter. Even at $15.00 for 4 c.f. the amount you would have to apply to 640 acres (not that big of a farm all things considered) and apply that in an amount that would make any kind of a viable difference would cost thousands and thousands of dollars.

Here's a run down on the various uses of perlite from the Perlite Institute. There's also a Vermiculite Institute.

No organization for rice hulls or pumice - yet.

CC

guest2012y · Feb 2, 2011

When I was a kid "they" had a mandatory flouride rinse every day at school....there's...uh...noth..ing..wro..ng...uh with..me.
I've heard that flouride is a by-product of aluminum production.
Seems it's one of those things that goes from being good to bad and back again every 10 years.
I'm not going to worry about the small amount of perlite I use in my mix. Has anyone ever tested perlite for the amount of detectable flouride?

mad librettist · Feb 2, 2011

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

lol I was just imagining being out in a kayak on the chesapeake, and a large mass of perlite floating by.

thank the dog this stuff is expensive.

Clackamas Coot · Feb 2, 2011

mad librettist said:
lol I was just imagining being out in a kayak on the chesapeake, and a large mass of perlite floating by.

Or if you were paddling about in a cranberry bog on a cold autumn morning.

CC

Corpsey · Feb 3, 2011

hey Coot, what % of pumice do you use in your mix?

Clackamas Coot · Feb 3, 2011

guest2012y · Feb 3, 2011

Clackamas Coot said:
25%

Gosh Mr. Coot,that seems like a heck of a golly gosh lot compared to me at around 15%...I suppose the addition of perlite in my mix makes up for the rest. I do think I'll go for more pumice on the next recycle as this last re-mix turned out one of the more water retaining recycled mixes I've done. My pots are damned heavy as is...no biggy,they can get heavier with the addition of some more pumice...'cause I grow HEAVY duty buds!

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

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