Hello all ! So I believe I read somewhere here it was mentioned (red lava rock dust) but currently can’t find it, maybe buried in another post somewhere. So I find myself in the middle of building more soil , and in low on basalt . I was going to go the cheap route and crush some red lava rock and not spend the money on buying pumice. Sounded good and what sounded better was the whole running it over with the truck when a stroke of genius hit , hey if a truck is good the front end loader would be better! Hmmm.. well it worked really really good. I am now left with the dust of what I was going to use for aeration. Can anyone tell me if I could get away with this dust & fine particles to be included in the final few cups of my rock dust count ?
It will work fine. Just don’t be alarmed later if you see the reddish coloration in the soil, or red stains weeping out the bottom drainage holes. Maybe a skid steer is “just right” sized for crushing lava rock. I tried it once with my F-350. It didn’t really work. Made a mess though. Cheers Os
Thank you OS! Can you tell me if mineral content is comparable to that of basalt or granite or even glacial dust? The red coloration is from iron content I assume?
Dog gone good question, Nacho I’m not 100 on this and maybe one of the Old Heads here can chime in and correct me if I’m wrong, I do believe that the coloration comes from iron content, and please don’t hold me to that I’m not certain but I do believe this to be the case, which if I’m correct brings up another question, the iron ratio it would add to the soil. After this build I will be sending a sample off for testing, these will be my first long term containers.
I’ve seen bagged ‘lava rock’ that was actually dyed concrete. I’ve only come across this once at HD, Vigoro was the brand name. Lava rock is basalt.
E-D thanks for the response! Can you please correct me if I’m wrong, Basalt/ black &red lava rock / pumice hell even perlite are all volcanic in nature, it is the mineral make up that separates/distinguishes the different materials? And maybe it was in one of your posts I had seen this before ( the whole dyed concrete thing) it’s “kolorscape “ red lava rock from Lowe’s that I crushed . My gut is telling me that I should open that crusty moldy wallet and just suck it up and order more basalt!
Yes all of those are volcanic in nature. Particle or mesh size is also important for those minerals to become available. I don’t like to use more than 1 cup per cf of mix. Any of the really fine material you created could be considered rock dust. If black lava rock is available get that next time since it has a higher CEC. Often landscape or Mason supply companies will have it by the yard for way less than the bagged box store stuff. I’ve never heard of that brand but it’s easy enough to distinguish concrete from actual lava rock. RD
I believe that iron is in a form that isnt easily taken up by the plant. I think it needs quite a bit of acid to free it up and make something like Iron sulfate which is plant available. Its not dyed if its real lava rock. The porosity makes it real easy to tell the difference between dyed concrete and lava rock. I use the stuff from Lowes that is packaged by greensmix. Folks have been using lava rock for a long time, so this is nothing new. The big difference between pumice and perlite is the temps it was exposed too. Perlite is exposed to higher temps and is more like glass. if you shop at Lowes look for the big 4 cu ft bags of perlite. Should be like $20. HTH Cheers Os
The Greensmix brand is what I see here too. I think the biggest difference between perlite, pumice and lava rock other than weight is CEC. Perlite is lowest at 3meq/100g. Lava Rock is better 15-40 depending on type. Pumice is around 75. With our compost and worms I don’t think it’s much of a worry just something to keep in mind.
RD is that 1cup per cu.ft of rock dust ? Reading the All organic notes and recipes thread (front page recipe) it says 4-6 cups per cu.ft., I have enough “Brix blend” basalt for 3cups per cu.ft, would it then be necessary to even worry about adding more rock dust? My mix is for 36 gallons 11 gallons of premiere sphag. Peat 11 gallons of ewc ( around 3.5 gallons of Colorado worm company castings/7.5 gallons of local castings (just started my worm bin)) 14 gallons of (70%pumice/30% pbh rice hulls) Amended with- 2.5 cups karanja cake (1/2 cup per cu.ft) 2.5cups kelp meal 2.5 cups crab meal 1 1/4 cups alfalfa ( 1/4 cup per) 5tsp mustard seed meal ( tsp per) 5 cups malted barley powder ( 1 cup per cu.ft) 30 cups bio char ( 6 cups per and pre charged) Basalt ( have 3 cups per) ( do I need worry about adding more rock dust?)
Yeah man 1 cup per cf is plenty. That mix has a ton of aeration so add more if you like. The problem with too much is it becomes heavy, compact and doesn’t drain well. Looks like you’re in Colorado? You may want to pull a water report since some areas have water that will need to be altered in one way or another. RD
RD I would love absolutely love to be in Colorado! Unfortunately I am considerably east on the map, and thank you for your help! I am aware that water is huuuuge! Even where I’m at I don’t exactly trust our water, and this even after a convo with the head local water guy, and some experience unfortunately, we’ll and being a noob ish kind of guy , I don’t have the years and foot work in such as you old heads here! But in time I will be there! Any ways my water I use a “boogie blue + “ filter and then cut it 50/50 with ro . My current grow in my 1st ever organic mix ( honestly had to “f” with it for while, was heavy used 50/50 coast of Maine lobster compost and a local ewc company, @TimJ got me right though, tore it apart added couple more gallons of aeration hulls I believe it was ) this was the first time I dropped the ph meter( scared the “s” out of me! ) I also recently sent a water sample to a local company “ Logan Labs” last week just curious to see what really is the deal with my water . I used the Colorado worm company to top dress in these bags. My first experience with cover crop too.
So look over by the 70% SiO2 column. You will see Rhyolite as volcanic and Granite as plutonic. Pumice would also fit over in that column as it has the same composition. Think Rhyolite with more dissolved gases. Now look over by the 51% SiO2 column. You will see Basalt as volcanic and Gabbro as plutonic. Scoria (the red or black lava rock) would also be in that column as it has the same composition. Think Basalt with more dissolved gases.
The distinction between volcanic and plutonic in the above chart comes down to crystal sizes. In a piece of granite, you will see individual crystals of quartz, muscovite, orthoclase, biotite, and amphibole. In a piece of rhyolite or pumice you will have the same composition, but visible crystals will not form and the rock will look like a homogenous greyish white rock. On the mafic side of the spectrum, gabbro will have visible crystals of plagioclase, olivine, and pyroxene. Basalt has the exact same composition, but looks to be a homogenous black rock.
@FunTimeGrowHap thank you ! So for future reference from my limited understanding it would be best to use a mix of rock dust ? And not just rely on basalt for mineralization?
Ya man. I prefer a mix of felsic rock dusts (granite, pumice, rhyolite) and mafic rock dusts (gabbro, basalt, scoria). That gives you pretty much everything an igneous rock can give!
@FunTimeGrowHap , thank you will take this to heart, current mix I have pumice and basalt, can you pontificate upon the efficacy of top dressing with a mineral mix ? I guess what I’m getting at is the rock dust in our mix is there for an anchor for micro - critters, mineralization and aeration I think those are the big ones, in a no till situation could a mineral mix help to add diversity if it’s top dressed? The mix I have come from a local shop to the north of me it contains Azomite Dolomite Gypsum Wollastonite Green Granite Basalt Black lime Rock Phosphate