Blue metal

[Tyrone]

I was talking to a palm nurseryman today, and he was telling me of some Dypsis decaryi that he bought from another wholesale nursery which had a blue metal style rock near the bottom of the pot. Reportedly this substance absorbs the fertiliser and releases it later over time. He reported that these D decaryi's went from 60cm high to 2.5m high in 2 years and were really bulky whereas his triangles from another supplier had much less growth. The wholesale nursery that he bought these triangles from used a fertigation system and watered them 5 times a day. So basically this rock substance released fertiliser to the plant long after the fertigation had stopped. Has anyone heard of this substance, or have any idea what it is exactly?

Best regards

Tyrone

[Jonathan]

Tyrone,

blue metal is crushed dolerite....its as hard as, well rocks, with a very fine, even glassy, grain and I dont think it would absorb too many nutrients. Its commonly used as concrete aggregate and road surfacing.

It can have a high iron content, so maybe thats something. Its possible that the added drainage allowed the plants to be watered and fertilised more frequently without drowning?

Theres a native nursery here that uses very fine <6mm metal as mulch in their pots.

Cheers,

Jonathan

[Tyrone]

Jonathan, I'm not sure if it actually is blue metal, but that's what it's supposed to look like. I'm not sure if the fertiliser chemically bonds to the substance, or whether it has miniscule little cavities which absorb the nutrient.

Best regards

Tyrone

[Kris]

Dear Tyrone

even i use it,we call it the blue metal for construction grade used to fabricate concreate slabs for kitchens & bathroon to place porcaline wash basin.

i never pot a plant without using the bottom layer with blue metal chips,since perilite is a substance that i came to know only after goining this forum.

i use this purely for my cycas & desert plants,i tried using this for my palms,the leaves to get burnt due to excess heat that these chips retain till the next watering.

so for guys living in cooler regions of the world,this can bring in the desired heat needed for those pots(bottom heat)..

I use this material in all my one or two liter plastic bottles,to close the drain holes of those bottles..you should have seen in all my seed germination & repotting works ! And in my personal opnion they are sterile & inert,no negative effect on the plants,except heat burn..

Lots of love,

Kris

[Cycadcenter]

Tyrone,

Over on the east coast of Oz we have always called crushed basalt "blue metal". The same stuff they use on roads etc and we use it as a base in all our greenhouses and shadehouses about 150mm deep over weed barrier as it tends to retain some moisture for humidity.

Bruce

[Tyrone]

Thanks guys.

Bruce, we call the same thing blue metal then. Does it have any fertiliser holding capacity that you know of at all?

Best regards

Tyrone

[Daryl]

Thanks guys.

Bruce, we call the same thing blue metal then. Does it have any fertiliser holding capacity that you know of at all?

Best regards

Tyrone

Tyrone,

We also have a product called 'Cracker Dust' which is the fines that come out of the crusher that they make blue metal with. This is basically crushed basalt particles up to 5mm. It has a thousand uses, and one of them is top dressing lawns. You can just spread it around and a few days later the lawn is level and green!

Daryl

[Tyrone]

That is amazing Daryl. I'm going to have a look for something like that. From what you're describing, the crushing process does allow certain minerals to leach out and be available to the plant. I wonder if this would work well with New Caledonian palms which come from basalt rock and require similar soils.

Thanks for the info.

Best regards

Tyrone

Thanks guys.

Bruce, we call the same thing blue metal then. Does it have any fertiliser holding capacity that you know of at all?

Best regards

Tyrone

Tyrone,

We also have a product called 'Cracker Dust' which is the fines that come out of the crusher that they make blue metal with. This is basically crushed basalt particles up to 5mm. It has a thousand uses, and one of them is top dressing lawns. You can just spread it around and a few days later the lawn is level and green!

Daryl

[Cycadcenter]

That is amazing Daryl. I'm going to have a look for something like that. From what you're describing, the crushing process does allow certain minerals to leach out and be available to the plant. I wonder if this would work well with New Caledonian palms which come from basalt rock and require similar soils.

Thanks for the info.

Best regards

Tyrone

Thanks guys.

Bruce, we call the same thing blue metal then. Does it have any fertiliser holding capacity that you know of at all?

Best regards

Tyrone

The red basalt soils derived from basalt are very high in Iron hence the red colouring so it is feasible that some iron/greening benifit could be gained from using cracker dust as a lawn topdressing.

Bruce

Tyrone,

We also have a product called 'Cracker Dust' which is the fines that come out of the crusher that they make blue metal with. This is basically crushed basalt particles up to 5mm. It has a thousand uses, and one of them is top dressing lawns. You can just spread it around and a few days later the lawn is level and green!

Daryl

[Ken Johnson]

I want some cracker dust! Where can I get some down here in dolomite land.

[Kris]

Just bumping it up ! Certainly with visuals..of the blue metal..

By the way the cracker dust we use it exclusively for filling the pits taken while we bulit concretised structures..that is the fountation foot is closed using this cracker dust not soil or dirt..

Love,

Kris

[Walter John]

Just bumping it up ! Certainly with visuals..of the blue metal..

By the way the cracker dust we use it exclusively for filling the pits taken while we bulit concretised structures..that is the fountation foot is closed using this cracker dust not soil or dirt..

Love,

Kris

Thanks Kris, if I had used that method in the past, it may well have prevented some of my losses.

[Tyrone]

I bought half a trailer load of cracker dust today for $24. I used it in the bottom of the pots of some Wodyetia's and a Bismarckia, and filled the rest of the pot with sand as an experiment. The Wodyetia's have been hooked up to a gravity fed fertigation system, and will be drip fed dynamic lifter tea, which has been spiked with seasol and powerfeed. I'll see if I can really speed these things up, and if the cracker dust does the job.

Best regards

Tyrone

[fan palm]

was wandering if you had any success using the crusher dust/crackerdust tyrone? what sort of rock are they getting this from on your side of the country? we have several quarries in the area producing this mainly for road works/construction from volcanic basalt. This local company produces the same product in powder form and claim it significally increases yeilds in crops and reduced risk of desease. I might grab some and see how it goes.

cheers

[BS Man about Palms]

Missed this the first go around. Any info on it here?

[MattyB]

I've never heard of such a thing here. Hmmmm.

[fan palm]

hi guys, crackerdust or crusher dust is whats left over after the crushing of volcanic basalt for roadworks. it ranges from about 4mm down to dust particles. the company that i posted above, grinds this down further to make a consistent powder like substance. i have been using the crusher dust sparingly for a fair while in potting mixes but would like to find out a bit more before i start using it as a main ingredient like its ph etc. the only darwback i have experienced so far is that it is quite heavy.

cheers

[Tyrone]

Harry, this is a real blast from the past. Yes I did experiment with this a bit. Daryl actually gave me the idea I think. I was using it in my potting mixes a bit, but typical me, used too much in the mix.

Anyway, the cracker dust, blue metal dust I used was the smaller particles, a by product of blue metal manufacture for roads etc. There is some larger stuff in it (around 3mm) and smaller very fine dust in it too. I think the original rock is a granite basalt style rock mined in the hills here. Basically the theory is the finer you grind the particles the more of the minerals are available to the plants and soil etc. The hills around here have a bit of aluminium in them, which can present some problems, blocking iron uptake.

Basically in a potting mix, I would use maybe less than 5% cracker dust. I was using up to 50%, and while the plants did fine initially, some developed iron deficiencies and the fine rock particles actually become clay, which is very undesirable in a pot. I don't use any cracker dust in my pots now, and just stick to a good free draining potting mix and good ferts and trace elements. Blue metal dust has a pH of around 9. So if you have high pH soil already I wouldn't recommend it. If you have acidic sandy soils that resist rewetting, a few cms of this spread around cures rewetting problems. It does something electrically to the surface tension of the water. I've done this in my garden and it works. I think with this product less is more. It will provide some structure and some nutrients to gutless soils like mine, even better if you add organics with it. Where it does seem to shine is in a compost heap. The worms actually digest the fine particles and help mince it all up. I think this is where the dust really will do better than simple soil applications. Again I wouldn't over do the dust. Just 5 -10% in a compost heap and I think this would create a mineral rich compost ready to be spread on the garden.

Hope this helps

Best regards

Tyrone

[fan palm]

thanks tyrone, that makes sense as i have had some yellowing in the leaves in some are plants (not palms) that were in a heavy crusher mix. gotta invest in a ph tester:rolleyes:

thanks mateB)

[peachy]

My first house in Melbourne was one of old bluestone terrace houses and I had the most gorgeous blue hydrangeas there you ever saw. Coincidental ? I think not. A few palms I have bought in the big plastic bags were sitting in blue metal with a bit of dirt mixed in. I found that I have to get them in the ground PDQ or lose them from dehydration. Not having a ute or trailer anymore, I can only buy it in small bags (about the same size as the 25litre potting mix bags) and they charge between $16 and $20 each for them, so experimenting is not a viable option. It's bad enough paying $8 each for the little bags of coarse sand.

Peachy

[Al in Kona]

hi guys, crackerdust or crusher dust is whats left over after the crushing of volcanic basalt for roadworks. it ranges from about 4mm down to dust particles. the company that i posted above, grinds this down further to make a consistent powder like substance. i have been using the crusher dust sparingly for a fair while in potting mixes but would like to find out a bit more before i start using it as a main ingredient like its ph etc. the only darwback i have experienced so far is that it is quite heavy.

cheers

This sounds like what we have here in Hawaii (which is crushed volcanic basalt - blue rock) and is used a lot for roadworks or base for any concrete jobs, etc. It comes in several crushed size grades. I've purchased one called "3/4 minus" to use for pathways or fill in between larger size rocks. 3/4 minus refers to particle size = ranging from 3/4 inch down to fine dust particles. It is very heavy (dense) and packs quite well. I don't know what the ph is but I've never heard of anyone here using it as a soil planting medium.

[Tyrone]

hi guys, crackerdust or crusher dust is whats left over after the crushing of volcanic basalt for roadworks. it ranges from about 4mm down to dust particles. the company that i posted above, grinds this down further to make a consistent powder like substance. i have been using the crusher dust sparingly for a fair while in potting mixes but would like to find out a bit more before i start using it as a main ingredient like its ph etc. the only darwback i have experienced so far is that it is quite heavy.

cheers

This sounds like what we have here in Hawaii (which is crushed volcanic basalt - blue rock) and is used a lot for roadworks or base for any concrete jobs, etc. It comes in several crushed size grades. I've purchased one called "3/4 minus" to use for pathways or fill in between larger size rocks. 3/4 minus refers to particle size = ranging from 3/4 inch down to fine dust particles. It is very heavy (dense) and packs quite well. I don't know what the ph is but I've never heard of anyone here using it as a soil planting medium.

That sounds like it. A very large nursery over here was using small amounts of the 3mm or less stuff in their potting mixes. They don't use it now. Someone told me the staff were not happy with it, because using it rips your hands up. It can be very sharp.

Best regards

Tyrone

[Kris]

Seeing is believing....

This washy filifera has not rotted after a year long exposure to hot wet tropical rains ! And even the B.Armeda is alive but not fast growing as its in semi shade region of our garden.

Love,

kris