Make clay grow media myself?

[AquaTex]

I was wondering if anyone had anything they could offer in the way of information on home made LECA type material. I have all the clay I could ever want and was thinking of making a kiln to fire the clay. I am not sure, however, if there are any methods I could use to make the clay porous or if I had to seal the clay in any way before or after firing. Has anyone ever tried this themselves? Or does anyone have any ideas? So far I thought about possibly....using a melon baller and scooping them out individually, making a half sphere mold and filling/punching it out, or making long clay "ropes" and cutting the ropes into small pieces.

Before anyone tells me how long it would take to make a grow media myself and how much effort I would have to expend, let me just say that I live on a farm in the country. Here I have a lot of time and limited resources, so I am trying to do the most that I can with minimal purchases. Thus, I am exploring the idea of making my own grow media. Any information would be greatly appreciated!

[davidstcldfl]

Hi AquaTex, welcome to the forum... :)

I took a pottery class a few decaes ago... :lol:. If I remember, clay that has been fired, is porus, if it hasn't had a 'glaze' applied to it.
Rolling out the 'ropes' and cutting them, sounds like the way to go.

Will you try building your own kiln, or maybe buy a used one ...? Again, trying to remeber...the kiln is slowly brought up to a very high temp and held there for quite awhile, then slowly cooled.
Sure hope it works out for you... ;)

[keith_r]

a member here (that hasn't posted in a while) did some experiments with a mixture of goat dung and clay (that he fired after mixing)
bullwinkle.. are you still reading here?

i think his blog is 120 things in 20 years?

[AquaTex]

Thank you for the ideas! And for the Bullwinkle info. Someone on the BYAP forum actually gave me a link to his "goat dung scoria recipe." After a little bit more research, I think I will be ready to experiment!! I do not have goat poop, but I have plenty of chicken manure.

I am going to try to do a kiln or something of the like in a home made fashion. The closer to DIY, the better. Especially down here where resources are scarce! It may take several attempts to get right, but if I can get the correct mixture and fire ratio, I think it will be a really fun, if smelly, project.

[bsfman]

Thank you for the ideas! And for the Bullwinkle info. Someone on the BYAP forum actually gave me a link to his "goat dung scoria recipe." After a little bit more research, I think I will be ready to experiment!! I do not have goat poop, but I have plenty of chicken manure.

I am going to try to do a kiln or something of the like in a home made fashion. The closer to DIY, the better. Especially down here where resources are scarce! It may take several attempts to get right, but if I can get the correct mixture and fire ratio, I think it will be a really fun, if smelly, project.

One of my other hobbies is pottery, and I recently built a home made kiln. I just did the first bisque firing in it a week or so ago, and it worked perfectly. Here's a link to a video of the firing:

[youtube:1toubrvs]http://www.youtube.com/watch?v=nRC_wunARes[/youtube:1toubrvs]

Not to burst your balloon though, but by the time you add up the cost of the kiln and associated components, the multiple times you will have to fire it (and buy propane) to get a meaningful quantity of media, and the labor involved in making the little clay balls, I really think it would be cheaper and easier to just go buy the media. If you do decide to go ahead and make your own, you might want to try using paper clay rather than mixing goat turds in the clay. Paper clay is pre-mixed with macerated paper which burns out during the firing leaving an open and porus clay body.

Good luck whatever you decide to do! :)

[bsfman]

Some additional thoughts on making ceramic media: If you live on a farm and have a nice supply of wood, you might consider building a wood fired kiln (much cheaper than propane). Do a YouTube search on wood firing and kiln building. You could probably cobble together a suitable kiln out of brick or stone and clay if you have natural clay on your property. You could use a leaf blower directed into your wood fire chamber to achieve hot enough flame. Alternatively, you could use coal rather than wood if coal is readily available to you.

Dried cow or horse manure, or even fine sawdust mixed with your natural clay would provide porosity. You wouldn't want to fire the media too hot either. Clay starts undergoing ceramic change from clay to ceramic at 660F, and what's known as "quartz inversion" at roughly 1065F. To complete the burnout of carbonaceous material, you would want to take the temp up to about 1700F. That should be plenty hot enough for your purposes. Hotter than that, you would start losing porosity which is something you don't want. Terra Cotta pottery is normally fired between 1432 and 1832F, so something in the 1500-1600F range would probably be ideal for your purposes. Even if you still have a bit of carbon or sulphur in your clay at that lower temp, it's not going to hurt anything.

As far as manufacturing the media, the simplest way would be to roll out a slab of clay with a rolling pin about 1/2 to 3/4 inches thick, and using a knife, cross hatch cut it into 1/2 to 3/4" cubes. WAY quicker and easier than rolling it and cutting it or scooping it out with a melon ball cutter! Your plants won't care if the media is round or cubical anyways! You could use large terra cotta flower pots to contain the media during firing. Support the flower pots on stacked firebrick pillars above your fire pit or propane flame.

You need to make sure your clay is bone dry before firing it or you risk it exploding and disintegrating inside the kiln. Temperature and humidity determine the drying rate. it could take a week to a month for it to sufficiently dry. If you roll out and cut your clay on sheets of drywall, the wallboard will help leach moisture out of your clay. Make sure there is plenty of air space between the rows of little cubes as they are drying. A fan blowing constantly blowing air across the media will speed the drying.

Let us know how it works if you decide to give it a try and by all means, take pictures! :)

[davidstcldfl]

Cool info bsfman... :)


the simplest way would be to roll out a slab of clay with a rolling pin about 1/2 to 3/4 inches thick, and using a knife, cross hatch cut it into 1/2 to 3/4" cubes.

Quicker, yes...I think it 'may' tend to pack too tight when added into the media beds....'?'

I think the 'ropes' would be pretty quick too.
Maybe even get kids in the neighborhood to help. It's a given, every kid would want to make snakes.. :D


Love my Farside
http://i931.photobucket.com/albums/ad157/davidstcldfl/Myfavoritefarside.jpg

[bsfman]

Quicker, yes...I think it 'may' tend to pack too tight when added into the media beds....'?'

I think the 'ropes' would be pretty quick too.
Maybe even get kids in the neighborhood to help. It's a given, every kid would want to make snakes.. :D


Good point, David. The quickest way to make "ropes" would be to roll out a flat slab, Slice it into narrow lengths, then roll each length a couple of times to round them out. Lay the lengths out parallel and use a machete or similar long blade to cut the ropes simultaneously into small cylinders roughly equal in length to their diameter! :)

[keith_r]

in the meantime.. gravel works fine..

[David - WI]

TXI has expanded shale at their locations all over Texas, I think... you could probably pick up a "lifetime supply" in one trip with a truck or trailer?

[AquaTex]

I have been thinking of the time/money factor vs. the ease of buying as well, Bsfman. And I definitely agree that it might just be worth it to buy instead. The biggest problem I think would be the kiln building, not the actually preparation of the clay.....I have no pottery experience, so it would all be experimental for me :o If nothing else, I will keep contemplating and experimenting with the goal of making my own grow media in the future!

Gravel may indeed have to do. I found a place in Dallas that sells expanded shale. Dallas is a good half of a day trip, but might be worth the drive. I will have to check into TXI, though. Another idea is to go to the plot of land that my family owns on the Blanco River and harvest some river stones (composition check is a must, but I have HCL!!). The river stones might be good middle ground between buying and making??

Other than the fact that I am trying to do my first system on a restricted budget, I am also concerned with environmental detriment in the way that some of the stone and clay is mined.

[bcotton]

Fair warning. While expanded shale is advertised as inert, i have not found inert expanded shale in texas.. i dont know if it's just hauled in the same trucks as limestone or what, but 3 loads now and it buffers to about 7.6-7.8. Maybe its just not really inert?


7.6 a little high for plants but i havent seen any issues that i would contribute to nute locking/high ph, if anything it's made it easier becuse i check ph a lot less frequently and i dont have to add anything to bring PH up after nitrification.

expanded shale cost compared to the hydroponic supplies is unbeatable.

In all likelihood, river rock around here have the same PH related issues only heavier and less porous.



brian

[120ThingsIn20Years]

Just in case anyone stumbles across this old thread...

I was wandering around the internet as I tend to do, and found myself mentioned in this thread. <wave emoticon>

The goat dung scoria was only a small sample (half a cup) made in my household wood burning heater (turns out that's not recommended if you are married). The goat dung was there to provide organic material that would be burnt out in the firing process leaving a stack of holes and an increase in surface area. A better alternative if you live in the modern world would be sawdust as someone mentioned. Also as mentioned, this would not be an inexpensive way to make media unless you lived in an area with a lot of clay and a lot of firewood. Goat dung is full of un-digested organic matter like grass, twigs, rose thorns, hand rails... whatever

I've been a potter for a few zillion years, and noticed something that might be of interest in my early days as the mixer of clays.

When you mix clay in a mechanical mixer, and dont add quite enough water, you tend to get little balls forming.

A cement mixer would probably work.

The size of the balls seemed to correlate with the amount of water (or lack there of)

If you dug clay out of the ground that was pretty dry, put it into a cement mixer with some sawdust (I'm guessing 1 part sawdust to 3 parts clay by volume - but who knows) and gradually add water until it formed the correct size balls, it might... might ... be an inexpensive way to make a media if you couldn't source it from anywhere else.

Pile it all up mixed in with an absurd amount of wood and make a huge bonfire, and you will easily reach the temperatures required to fire it and burn out all the organic material.

The reason the original goat dung scoria was made was actually just a test of a thing I call "the invention engine" which is a process I've been developing to solve problems. Someone on a forum said they had zero access to media as they were in a[n] African village miles away from a store (or something), so I dragged out the invention engine to see what I could come up with using only locally sourced materials.

It was never intended to be used where suitable media could be bought, and even then was borderline useful at best. More of a thought exercise really.

Having said that, I'd love to know if anyone ever made any media themselves using any technique.


-BullwinkleII