Yes, I stated that I'm not worried about the aluminum, all the same I won't use aluminum sulfate either. Although it may be safe, I worry about toxic levels. Just because lead is in all soils doesn't mean it's a good idea to add more. Same with aluminum. And if you mix turface without a mask, you will be exposed to it. As far as water absorption Axis noted that turface holds 95% of it's weight in water. Pumice only holds 15% and DE holds 142% Try diatomaceous earth in your tests. Optisorb is about the largest size available to home gardeners. Axis makes an excellent size, but is for commercial use only. Numerous studies document it's use as superior to most other amendments. Such as " Effects of diatomite on soil consistency limits and soil compactibility" by Ekrem Lutfi Aksakala, Ilker Anginb, , , and Taskin Oztasa Or "Effects of diatomite on soil physical properties" by the same authors. Also "Sustainable effects of diatomite on the growth criteria and phytochemical contents of Vicia faba plants." Mona M. Abdalla* Department of Botany, Faculty of Science, Ain Shams University, Cairo, Egypt. The Axis company also has great info on all amendments. As far as particle size, do a test. Fill a pot with sand, and one with gravel. Stick a pole in, and see which one gives more resistance. It seems to me gravel would. But I might be wrong? I don't know physics well enough to figure it out on paper. Ah and pumice is further dashed to the ground and called a fake, not a single user rises to defend. Well we can agree to disagree, my day job is a laboratory researcher,or was, I'm retired. If turface has various pore sizes then it is not very well made. Thanks for pointing that out. So you do not believe the manufacturer? Controlling pore size in fired clays is often accomplished with the use of polymers such as Polyethylene glycol. This process is extremely important to control how well purifiers work, or how well they hold up with the addition of salts. You are incorrect about the pore size. Yes pore sizes differs, but that process is used to make different products, and is very controlled. Turface is meant to have small pores size or it would ineffective in it's intended use. The porosity of fired clays is extremely important to have a consistent product such as fired brick used to built houses. Varying pore sizes will compromise the strength of the brick. Selling a product and manufacturing one are very different things. The pore size I reported is for calcinated clay. Range of pore sizes is from .1 -.01 microns. Median is .045 . Plants need a .2 micron minimum pore size to utilize. This info is from a study by Andreas Kalytta-Mewes, Kathrin Mattern, and Armin Reller University of Augsburg, Chair of Solid Body Chemistry Georg Armbruster Soil Laboratory. The pore analysis in the study was conducted by Quantachrome,Bavarian Institute of Applied Environmental Research and Applied Technology. Of course it appears none of these sources trump Al. Who has not provided any data at all to back his claims. Please prove to me that pore size is bigger, thinking Al is right because you sell clay products is not proof. After saying all this will turface work? Yes, it will. Works pretty good! Is it ideal? No, it's not, but what is? It's still worth trying for sure. It didn't work for me, but that means nothing. it has worked well for others. It would be nice if it allowed easier access to stored water, but it does store water, and air, and it lasts a long time, maybe 20 years. That's decent. It's a decent product, or appears to be. It would not be on the market if it didn't work. I know it's not meant for potted plants, but it is meant for grass. DE seems a better product, it has it's own problems. it is marketed though for plants more than ball fields, although it is marketed for that too. It's marketed for large commercial gardens. I use it in my garden. I use turface too for my grass, works well. Just not that well in pots for me. All i said that it didn't work for me. Sorry blame me, it's what you usually do when the mixes fail, you blame the poster. Many have said DE doesn't work for them. I actually believe them. All gardening is local. This post was edited by Drew51 on Mon, Dec 29, 14 at 15:33

Hi all, not sure I'd classify myself as a "grower" but I do dabble with my blue spruce. I have maybe a thousand I've grown from seed, ranging in size from 3" to 12" now, and still in 5" plugs. This fall I will transplant about 250 of the largest to 1 gal. pots and see how it goes (and move to 2 gal. next year, once I see how things develop. I've been researching soil-less container soils. I can buy Pro-Mix or the Sunshine Mix #4 but am concerned that the pH will be a bit high. I understand that in order for a blue spruce to be "blue" (at least for the 50% that have the ability to turn blue from the regular kaibab variety - although I have many "Majestica" that claim 90% will turn blue, and have some (claimed to be) "Misty Blue" which apparently were selected from the best of the Majestica orchard, but are no longer harvested) the pH should be about 5.5 or even less. I think both of the above pre-mixes have pH's greater than this. One mix I saw called for about 20% perlite, 20% vermiculite, 60% sphagnum peat moss, and 1/2 cup each of bone meal, blood meal, and dolomitic lime per 8 gallons of mix. I suspect that if I were to use this mix for blue spruce, I might eliminate vermiculite and reduce the lime to maybe 2 tablespoons? It looks from this thread that using primarily pine bark fines may be adviseable? I suppose I could also substitute turface for perlite although not sure I could find same. I don't know if I'd need any other additives like CRF? I'm hoping to keep costs down. It seems to me that I can mix my own soil for about 1/3rd less cost than pre-mix, unless I'm missing something? I have hundreds++ more blue spruce coming down the pipeline, so cost is important. Sorry for being so new at this. It was enjoyable planting the seeds (all outdoors, which was a challenge) but now a few years later I want to keep going with this, so am on to the potting stage. Any advise is helpful.

Sure! I can certainly post back once I have some results to report. I have a tendency to dive much deeper than necessary into details of any hobby I take on...in the end I'm sure a lot of these details aren't critical. I'm in a detail-oriented profession so I think it's just a natural mindset for me to fall into. In this case though, the more I think about the whole coco media buffering, the more I realize that most people who have to worry about it are growing in 100% coco-based media or are utilizing hydroponics. Any of the negative effects I would experience from unbuffered coco (if there would actually be any such negative effect in practice) should be largely offset by the fact that the coco is only 1/3 of my mix. Also I'm applying a fertilizer with every watering that has calcium and magnesium in it so the cation exchange issue should theoretically only be temporary as the media should balance over time. Some of the research I've read indicates that it is more important for the coco to be properly washed to a low electrical conductivity than it is for the cation exchange complex to be buffered. This is because seedlings and young plants are substantially more sensitive to the negative effects of high sodium exposure than they are to a temporary deficient quantity of available calcium/magnesium. The good news is that most of the high quality sources of coco products are washed to a very low electrical conductivity, it's just hit or miss whether a particular manufacturer buffers or not. Since I'm going to be growing a few plants each of some of my aji limon peppers and purple jalapenos, I think I might try buffering some coco and not buffering the other coco and see if there is a noticeable performance difference between the two if the rest of the mix is the same. It would obviously only be anecdotal, but it would still be an interesting thing to see!

I am actually curious now to test my coil mix. I purchased an NPK probe to test the ph from China. The oyster shell idea came from Samuel at Exotic Cactus and Succulents who is a well-known master grower in Florida. In my location, I can get them easy and cheap and they also work great for seedling mixes. The brand I use is called MannaPro Oyster Shell which also has coral calcium. According to his description: This is the same fine gravel I use it as substitution for Dyna rock, I'm using this oyster shell for years with the best results for all my seedlings as showed on my seedling kit for sale, using oyster shell as top layer for seedlings avoid fungus keeping the top dry and clean, I use it also for mixing a special blend to plant a very valuable plants like lophophoras, aztekium, pelecyphora, ariocarpus, lithops, rare mesembs, or any plant that need a very good drained soil. I live on the Crystal Coast of North Carolina and also had great luck using Red Lava Stone (my favorite), horticultural pumice and GS-2 stone or river rock. But, they ARE pricey and not readily available around here. I also use perlite when all else fails, but I am just not a huge fan. Finding a soil mix that works for your area and your watering style is the key to success. Some of my cacti have grown big now (24-inch pots) and I like to save money when I can. After many years together they seem to understand my routines—get with the program—and seem to be happy. Again, I am NOT an expert and still have much to learn! :-)