This thread will be the official non scientific (no lab coats or beakers will be involved) testing of Oil-Dri premium absorbent. It can be found at Walmart (at least around here) for $3.50
Bag compared to Napa 8822, The Napa is a bit bigger with more stuff inside. Should be noted that Oil-Dri specifically states that it can be used for soil mixes to retain water.
A small handfull of each, Oil-Dri left Napa right. Oil-Dri is a little bigger, Napa appears to have many more fines though that may just be the bag I got. I sift away the fines so the less there are the better, I do save some of it for rooting cuttings though.
#1. Submerged in water test. So far after several hours it is holding shape perfectly and not turning to mush, I'll let it sit for at least a week
Any suggestions as to what other tests should I do?
The important properties are how much water it holds, how much air it holds, and pH. Ideally the granules will be insoluble enough that the pH won't matter, but its worth testing. For example Oil Dri quote a pH of 5 for the Montmorillonite clay granules which is most likely what you have.
We already have water retention tests here for NAPA and perlite, and I added my own test for the Moler cat litter.
I believe the NAPA is inert and does not contribute to pH in either way. It says it can be used in soil mixes to retain water, interesting.
The reason I like NAPA is because it doesn't hold as much water as you would think, far less than soil would at least, hopefully you can test the oil-dry with some rot prone species and see what you get.
I would grab the wet material and give it a squeeze. See if it turns to mush then. If so just think what will happen when the pot gets root bound, and is let to dry out completly. A big ol clay rock lol. Only reason I say to keep testing the Wal Mart stuff is cause of the crap I was sold. Hopefully this stuff works out for ya, and happy testings!!
I find it interesting that the Oil Dri is the same color in and out of the water. Next to the NAPA, it actually looks wet from the start? I would imagine that if it was soft-turn-to-mush clay, then the color would darken as it gets wet.
All Cacti are succulents, but not all succulents are Cacti
My cat litter hisses when it is thoroughly dried out. When it is just about dry it doesn't hiss, so I'd guess there is still some water deep inside that hasn't evaporated yet.
One of my top dressing grits also hisses. It is flint based and the paler yellow flints are quite porous while the dark glassy flints are not.
I bought some Oil-Dri for the first time & have used it in my gardens & flowerpots, although they're not planted with anything yet. I have a lot left over I will add to my cactus mix for my repotted cacti. I probably won't notice any real positive or negative effects for a few months, but I'll keep you posted. You're right about it being easier to get; I don't know if it's only found at Walmart or not.
Catch a falling star--but don't try it with a cactus!
Don't know about Wal-Mart, but up here, seems like every Rona Hardware Store carries it at a much cheaper price than the Napa stuff. I'm gonna try it and hope it doesn't affect the soil's pH.
I might also try to buy the Napa stuff and have two similar plants one being in Napa and the other one in Oil-Dri. Thing is... I might not be experimented enough in cacti to actually see the difference if there's one.
Last summer I used the Oil Dri in a few outdoor pots. As best I can tell it hasn't turned to mush or affected the ph greatly as the cactus in it are alive and growing this Spring. If anything drastically changes I'll be sure to post about it.
Thought I'd update this topic as I've been using Oil-Dri more and more in my mixes.
1) It doesn't turn to mush, at least not after two years. In July 2009 I potted up an Opuntia in a 15" wide hypertufa bowl using lots of Oil-Dri in the mix. So its seen over 100" of precipitation and spent months as a frozen brick. This spring when I dug up the plant the OD was perfect just like it came out of the bag.
2) When using Oil-Dri I'm seeing the soil mix dry out faster than when using Napa 8822 in the same proportions, same topsoil. I don't know exactly why but it is just drying out faster. Since I leave my plants out to be rained on, even 3-4-5 days in a row, I like the fact that it dries out faster.
My conclusion after two years: I like Oil-Dri
The price did go up at Walmart, I got another bag at $4 something this time. The bag changed a bit too, it no longer list water retention in soils as one of its uses.
My only concern would be product consistency. Wal-Mart is infamous for their cost-cutting ways. It isn't all bad, but certainly they "flex their muscle" on the buying end and ultimately give the order to the "lowest bidder". In other words, they may switch suppliers and continue to sell it under the same name, but a different material.
Not saying that happened or is only something Wal-Mart does. However, I would suspect that NAPA would assign a new part number to product from a different supplier - it's just the "auto parts" way. Millions of SKUs!
All Cacti are succulents, but not all succulents are Cacti
