Does anyone know where to find cheap pumice/lava rock online?

[Team Microbe]

I'm looking for some pumice or lava rock for a no-till soil mix I'm building this month, but I can't find it much cheaper than $45 shipped (for 1 cubic foot). It would cost $400 just for aeration if I were to do that for a cubic yard recipe, and that's a lot of $ for me personally.


Does anyone have any good sources to buy pumice or lava rock in bulk?


Any info is much appreciated folks

 

[Granger2]

TM,
Check out local sources of Lava Rock. Take a shovel [flat blade] and some hev-du garbage bags or whatever, and ask if you can bag your own. Almost always there is fine stuff on down to granules around the edges. You'll have to work at it a little but it might work out for you. Check different places. Good luck. -granger

 

[Former Guest]

Places that sell topsoil, mulch, rocks by the cubic yard in bulk will have pumice for super cheap. Like less $15 for a half yard. I would look under landscaping in your local area.

 

[EclipseFour20]

Two of my posts from another thread regarding pumice & lava rock--

Here is some information that got me rethinking the value of pumice as a growing medium aggregate.

"Pumice possesses large pores and consequently its volumetric water content decreases sharply as water tension increases. (Boertje, 1994; Raviv et al., 1999). The water-holding capacity of pumice is relatively low compared with rockwool, perlite or organic substrates and may limit water and nutrient uptake by plants, especially in hot climates (Raviv et al., 1999)."

"Pumice has no buffering capacity and possesses a very low surface charge, derived mainly from impurities of carbonate and metal content ...However, caution is recommended when using new pumice material because high concentrations of Na are leached out at the beginning of use."

Source...UN's Food and Agriculture Organization....http://www.fao.org/hortivar/scis/doc/publ/8.pdf

Jump to the pdf file page 43...that is where the inorganic substrate discussion starts...and page 50 for pumice info.

Lets just say, my growing medium is now pumice free. Cheers!

Referring to the FAO file I linked to above, check out pdf page 52 under the section "2.5.1.5. Pyroclastic materials (tuff)"

Tuffs possess a buffering capacity and may adsorb or release nutrients,
especially P, during the growth period (Silber et al., 1999; Silber and Raviv, 1996).
The chemical stability of tuffs depends on their mineralogical composition.
Volcanic glass dissolution is very rapid while that of secondary minerals, such as
kaolinite and halloysite, is slower. Hence, non-weathered materials containing a
high concentration of volcanic glass, like black tuff are unstable and dissolve
easily in solution below pH 6, while red and yellow tuffs are more stable (Silber et
al., 1999). Introducing plants to black, or even red tuff, after equilibration with an
acidic electrolyte (pH below 5) may be risky due to Al and Mn toxicity

The CEC rates for the different types of volcanic rock are: black is 107, red is 285, and yellow is 601. (Table 8. Mineralogical composition of various tuff types.)

Seems that not all "volcanic rocks" are equal....just like most things in life. Hmmm, "yellow tuff" think we might have to find some and run some tests....side by side.

Keep up the unconventional thinking!

BTW--I no longer use pumice or lava rock.

 

[vostok]

I'm in the same situation with coco, my grow shop went bust, (online sales ...?) and so re verted to soil grows, as the price of buying online and cartage is too much

like many growers since the '60s we gotta use whats at hand

the tough sneaky bastards we are ....lol

 

[Team Microbe]

Two of my posts from another thread regarding pumice & lava rock--





BTW--I no longer use pumice or lava rock.

I never knew that before... is there any way to "wash" the sodium out of pumice that is typically released during the beginning of use? Sort of like you do with coco? Or is it not that easy... I feel like I just answered my own question lol

"Pumice is an inert aluminosilicate material composed primarily of silica and Al-oxide, but may also contain metal oxides, calcite, or salts."

I'm definitely second-guessing pumice now!



Lava rock sounds like it's better than pumice after reading that article (thanks for sharing btw), it just needs to be in a medium that's of neutral pH to prevent Al and Mn toxicity, am I right?


What do you use now, and why?

 

[Team Microbe]

TM,
Check out local sources of Lava Rock. Take a shovel [flat blade] and some hev-du garbage bags or whatever, and ask if you can bag your own. Almost always there is fine stuff on down to granules around the edges. You'll have to work at it a little but it might work out for you. Check different places. Good luck. -granger

That's a good idea, what would those sources be exactly? I don't have any volcanoes near me

Places that sell topsoil, mulch, rocks by the cubic yard in bulk will have pumice for super cheap. Like less $15 for a half yard. I would look under landscaping in your local area.

Damn! Nobody I've visited carries anything except perlite so far, it might be time to make some 30 minute drives/phone calls though... $15 for 100 gallons worth is like 1/30 of the price they sell it for by the bag

 

[Granger2]

Check yellow pages or online for topsoil, mulch. I'm talking about places that sell in bulk, like dumptruck loads. They'll have grande piles of bulk materials- Compost, mulch, rock mulches like lava rock. Good luck. -granger

 

[Former Guest]

They should tell ya to wash the dust off your perlite. I punch a couple holes in the bottom and hose it down do it drains below. The dust is bad to breath in. Perlite is $6 half yard. I drive almost 2 hrs round trip to by fresh EWC from a farm that was promoted by some big guru here. I was just told they have a springtail out break so now I only have a mediocre source. I got some mineralized dirt all ready as soon as I feel better. Throw in some leaves newspaper cardboard and were good to go.

Bulk soil and rock places are where it's at. You can find those better than feed stores.

Lava rock is supposed to be one of the few mediums in hydro to house beneficials. I use Grow Rocks. Get them at the hydro store. Loads if surface area for holding air and releases the plant available form of silica: sascylic acid. It's expanded shale. Good stuff,

 

[Team Microbe]

LLB:

Springtails shouldn't stop you from buying more castings, they're a beneficial I thought? Do they do anything negative?

I wish my area was like yours, perlite here is $20 for 4 cu. ft. bags - that's the biggest size our bulk carrier provides us here. They have a ton of landscaping materials like rock and all that, but nothing for the indoor gardener and they sniff us out when we go there so I stopped going lol

"Dude so you're tellin me you're not using all of this soil to grow weed? C'monnn man."

"He's not gonna tell you either way, what are you stupid Larry?!" (his co worker)




I've got a bunch of rice hull bales sitting in my garage, if they didn't break down over time I'd use 100% rice hulls for aerating this mix instead of rock... can't win em all though I suppose

 

[Granger2]

Answer: Yes, Larry's stupid, and has no manners, no business acumen. What a douchebag. -granger

 

[EclipseFour20]

I never knew that before... is there any way to "wash" the sodium out of pumice that is typically released during the beginning of use? Sort of like you do with coco? Or is it not that easy... I feel like I just answered my own question lol

"Pumice is an inert aluminosilicate material composed primarily of silica and Al-oxide, but may also contain metal oxides, calcite, or salts."

I'm definitely second-guessing pumice now!



Lava rock sounds like it's better than pumice after reading that article (thanks for sharing btw), it just needs to be in a medium that's of neutral pH to prevent Al and Mn toxicity, am I right?


What do you use now, and why?

I replaced pumice/volcanic rock with perlite (it is neutral in pH and produces zero elements to the grow medium...other than "oxygen"). I use the large/medium variety. Then...when I did that, I had to re-calculate the proportions/quantity of my other aggregates so my water and air porosity #s were back on track.

One thing that helped me "equalize" the grow medium's porosity was to increase the amount of bark, specifically orchid rooting bark. It holds moisture/nutrients longer than pumice but produces zero air pockets. So bark + perlite = pumice? Kinda sorta.

The other trick to "increase air" to my grow medium is adding a 1" layer of airy aggregate (bark, clay pellets, perlite, diatoms, etc) to the bottom of the container before adding the grow medium. Sometimes the grow medium at the very bottom-center never really dries out resulting in diminished root growth...when compared other portions of the medium that are "drier" or not as "moist". By adding a layer of "airy aggregate" this allows air to enter the container via drain holes. Roots will plow through the bark/perlite layer and create a "second rootball"...first one being the roots in the grow medium. I used to use perlite but switched to bark as I am experimenting with recycling/reusing my soil...and like bark's ability to breakdown (not so with perlite...it just crushes but does not breakdown)....besides orchid rooting bark is less than $4 a cu/ft (fully decomposed, sorted and not green).

Of course pre-moistening the grow medium and "fluffing it" (adding air) prior to transplant does not hurt either...the fluffing creates crevices and "caverns" of air that roots grow in. Funny thing...same thing with cheap "ice cream"--mfgs whip it/fluff it which adds more air, making a 1/2 gallon look like a full gallon.

 

[blackpulpit]

Hello TeamMicrobe hope all is well, wish I could help you with the lava rock, got a lot of it here and matter of fact the very large Volcano just erupted yesterday and dusted everything with a layer of ash, including my outdoor babies and today 1 of them looks like it got burnt from the ash!…crazy stuff around here. I use the red lava rocks from a local company here and I wash it real good to get the dust and all off of it before using.

I forgot to ask you about your watering schedule, i have it but wanted to know the directions for agsil, aloe, etc is for what size gallon mix?

veg: 10ml agsil, etc, ect for 3 gallon, 5 or 10?

 

[Former Guest]

They are beneficial. That's why I was confused when the hydro store told me they won't sell them anymore. Most growers say it's a sign of a healthy soil but a few reported their populations exploded and they had issues but after they killed them, the plants got better. Predatory soil mites keep them in check indoors where natural predators are low. I have the worms in my bed so I am just using compost to build my base and I gave a bag for compost teas, springtails like hydro units and water so I'm sure I could identify them right away.

 

[Team Microbe]

I replaced pumice/volcanic rock with perlite (it is neutral in pH and produces zero elements to the grow medium...other than "oxygen"). I use the large/medium variety. Then...when I did that, I had to re-calculate the proportions/quantity of my other aggregates so my water and air porosity #s were back on track.

One thing that helped me "equalize" the grow medium's porosity was to increase the amount of bark, specifically orchid rooting bark. It holds moisture/nutrients longer than pumice but produces zero air pockets. So bark + perlite = pumice? Kinda sorta.

The other trick to "increase air" to my grow medium is adding a 1" layer of airy aggregate (bark, clay pellets, perlite, diatoms, etc) to the bottom of the container before adding the grow medium. Sometimes the grow medium at the very bottom-center never really dries out resulting in diminished root growth...when compared other portions of the medium that are "drier" or not as "moist". By adding a layer of "airy aggregate" this allows air to enter the container via drain holes. Roots will plow through the bark/perlite layer and create a "second rootball"...first one being the roots in the grow medium. I used to use perlite but switched to bark as I am experimenting with recycling/reusing my soil...and like bark's ability to breakdown (not so with perlite...it just crushes but does not breakdown)....besides orchid rooting bark is less than $4 a cu/ft (fully decomposed, sorted and not green).

Of course pre-moistening the grow medium and "fluffing it" (adding air) prior to transplant does not hurt either...the fluffing creates crevices and "caverns" of air that roots grow in. Funny thing...same thing with cheap "ice cream"--mfgs whip it/fluff it which adds more air, making a 1/2 gallon look like a full gallon.

I'm still on the fence about using perlite over lava rock, I almost see it as taking 1/3 of the volume out of my total soil volume since it's inert. If I were to add lava rock, I'd be providing little crevices to harbor microbes in that 1/3 of the mix. I'm just wondering if the small qualms of the lava (pumice looks to be "dirtier" so I won't be using it) really outweigh perlite's disadvantages in a living soil.

Btw thank you so much for that link, very informative! I never knew black, red, and yellow lava all had different CEC's... I wonder which color would be best to use for no till? The black has 100, red has 200, and yellow has like 600 CEC. What would you choose if you had to?

Hello TeamMicrobe hope all is well, wish I could help you with the lava rock, got a lot of it here and matter of fact the very large Volcano just erupted yesterday and dusted everything with a layer of ash, including my outdoor babies and today 1 of them looks like it got burnt from the ash!…crazy stuff around here. I use the red lava rocks from a local company here and I wash it real good to get the dust and all off of it before using.

I forgot to ask you about your watering schedule, i have it but wanted to know the directions for agsil, aloe, etc is for what size gallon mix?

veg: 10ml agsil, etc, ect for 3 gallon, 5 or 10?

That's crazy, I can't even picture that man. Talk about fertile native soil though! Lol

The recipe's in my threads are always for single gallon recipes, unless it's a compost tea recipe in which it'll be either 5 or 10 gallons. Can you link me to the page so I can edit the post and specify for future reference? Thanks brother

They are beneficial. That's why I was confused when the hydro store told me they won't sell them anymore. Most growers say it's a sign of a healthy soil but a few reported their populations exploded and they had issues but after they killed them, the plants got better. Predatory soil mites keep them in check indoors where natural predators are low. I have the worms in my bed so I am just using compost to build my base and I gave a bag for compost teas, springtails like hydro units and water so I'm sure I could identify them right away.

That's crazy, I've heard of things like this happen before actually. Too much of anything is bad I suppose, even if it's a beneficial. It has to throw off balance somewhere or another...

Dude when I discovered predatory mites I had a heart attack and started treating it like spider mites *slaps forehead*. After giving up I eventually realized I fought a pointless battle, and invested in a scope so that shit never happens again lol

This is what I went with, and upon fetching this link for you I'm now realizing that I paid like $80 for it last month...

 

[EclipseFour20]

Oh...one more thing about pumice I bought in bulk--they were loaded with symphylans and required to be "sterilized". Loads of fun heating 40 gallons of pumice to 180 degrees for 1/2 hour.

As to which volcanic rock I would use...probably the yellow, but the cost is ridiculous. Remember: "Introducing plants to black, or even red tuff, after equilibration with an acidic electrolyte (pH below 5) may be risky due to Al and Mn toxicity." Since cannabis can absorb heavy metals from soil at high rates (making it a good candidate for phytoremediation) I would be cautious of incorporating any amendment containing "metals" that I don't need/want.

Then we have a simple thing called "cost", the cost of perlite compared to other alternatives helped me decide...a 4 cuft bag of large perlite is cheap ($15-20) and no sterilization required.

 

[Team Microbe]

"Introducing plants to black, or even red tuff, after equilibration with an acidic electrolyte (pH below 5) may be risky due to Al and Mn toxicity."

So basically if you remain a stable pH above 5, lava rock won't pose that risk? Am I right here? If so, it shouldn't be of concern when used in a soil setting where pH swings between 6.0-7.0

 

[Team Microbe]

I found this stuff at the local hardware store, if maintaining a stable pH is all that's needed to safely use lava rock I think I'm going to go with this kind.

What do you guys/gals think?

 

[Former Guest]

I say use it. If it was such an issue, people wouldn't be using it so much. Just wash it first to get sediment off. Not sure if ya have to but it's recommended for hydro pellets and perlite.

 

[Team Microbe]

Ya good idea, I was wondering if I should rinse it off prior to using or not actually...

And good point - Blue Jay over at grasscity (the grower I look up to most out of all) uses black lava and red lava rock in his mix, and I've never seen healthier plants in my life. Of course it's not thanks to solely the lava rock, but if he's using it then I would bank on it not being risky if pH is stabilized like it usually is in a balanced soil