Nothing to quarrel with in your 1-8 list, but I would mention that perlite & vermiculite are very different in their effect on aeration. Perlite is actually a form of porous glass that is made from a mineral called obsidian (or an aluminum silicate rock). It's heated and kind of popped like popcorn. Vermiculite is mica that is treated in much the same way. Trapped moisture expands and creates lots of air pores in both products. In soils, perlite promotes drainage and improves porosity. It's also effective for starting seeds & cuttings. Actually, perlite holds quite a bit of water @ about 3/4 quart per gallon of perlite. The dry weight of perlite is about 7 lbs/cu ft. Wet, it weighs about 18 lbs for the same volume, so it holds more than 2-1/2 times it's weight in water. Vermiculite is about the same density, and has a even higher capacity for holding water and a very high cation exchange capacity. It also contains magnesium and potassium that are available for plant uptake, but it is not very durable and will compress if handled when wet. It also has a slightly higher pH than perlite. You probably should not depend on vermiculite for aeration as it collapses and loses its loft very easily. When I occasionally use it, I try to limit its presence in container soils to less than 10% of the total volume. Will Turface, sand, perlite and/or vermiculite add any nutrients/minerals as they break down? I would consider them inert, except for vermiculite, which can add some K and Mg. A couple of sites state that the optimal pH range for the solubility of certain minerals is between 5.0-5.5. I am just curious if this is only for very specific kinds of plants? And if not, why is a pH of 6.5-7.0 most recommended. I'll try not to complicate this, but some plants are able to add ions to the soil, changing soil solution pH to make other needed ions more readily available. We know there is a 'sweet spot' for mineral soils at around 6.2 - 6.7. I've always preferred to grow in a more acidic container soil. I even often add elemental S to certain soils to lower pH. Indoors, I add vinegar to my irrigation water at every watering. "Solubility of mineral nutrients are affected by substrate pH. Iron, manganes, boron, copper, and zinc are most soluble when pH is above 5.0 and below 5.5. On the contrary, as pH increases greater than 6.5, the availability of iron, manganese, boron, copper, and zinc decrease and micronutrient deficiencies symptoms begin to appear." Unless I misunderstand what you're pointing out, I see nothing contradictory about the original statement when the nutrients listed are considered as a group. Which of those ingredients is raising the natural acidity of the bark up to 6.5. Or is the bark that we are using treated in some way that the pH is raised? The bark is acidic, the Turface only mildly acidic (around 6.5), and the granite slightly basic. Because the bark pH is around 4.0 - 5.0 doesn't mean that when it's combined with other ingredients the o/a soil pH will be 4.0 - 5.0. The other soil ingredients buffer the pH of the bark. Is the top bark already composted somewhat and is that why it looks wet? . . . If I am correct, does the decomp of the top bark help provide nitrogen where the "raw" bark would not? The bark at the top IS damp, AND partially composted. I prefer this type of bark simply because it requires less N to compensate for N immobilization. Al

i Wineman: How are you? From what part of Mass are you from? Fafard is a great brand next to making your own which is what I prefer to do in most cases. Why don't you use Fafard 'nursery' mix which is composed of mostly bark and a small fraction of peat? There is also another that Rhizzo had suggested before and I can't think of it. I am not sure of what brand you are using since I never heard of #30. From the description of it, it seems to have too many fine particles and ingredients that encourage the mix to stay wet far too long for my citrus trees liking, especially up here in New England, and one that will compact within a very short time. All you have to do is add strained perlite and you are good to go if you find the nursery mix I know a few that add sand to amend their mixes, but it has to be very course washed sand as Toni mentioned or it will clog up your mix as Jojo mentioned. Sand can improve drainage in some cases, but it reduces aeration by filling valuable macro-pores in soils. Unless sand particle size is fairly uniform and/or larger than about BB size, I leave it out of soils. Why use sand and rocks at all? If you purchase a good potting medium that has pine bark as it's main component, at least 80% or more and adjust it a bit, then you are good to go. If you care to invest your time into making a fine mix as Jojo has kindly pointed out to you, then let me know and I can direct you to the sources for the ingredients. Hi Jean, Toni and Jojo! Mike

In addition to what Dori said: It's possible to take a long list of ingredients like yours which would otherwise appear to be perfectly fine on a "stand alone" basis (though you have some I wouldn't use - namely the sand and shavings), and combine them to produce an unusable soil. I too, embrace the KISS method when it comes to building soils & use as few ingredients as it takes to properly do the job. Also, there is practically no difference in the water holding capacity or the water release curve between coir and peat. Coir does compact easier/more quickly than peat, and it has a higher pH - something I would probably consider a disadvantage for citrus - and you need to watch for the possibility of a high soluble salts content in coir. Al

Found a fantastic link which explains the many forms of calcium: http://waltsorganic.com/ag-lime-dolomite-gypsum-oyster-shellwhat-kind-of-calcium-do-you-need/ Agricultural Lime: Calcium carbonate – CaC03 Pure calcium carbonate is used to help prevent the spread of various diseases, such as powdery mildew, black spot, and blossom end rot ... Adding Ag. Lime to your soil will also raise your PH making it more alkaline. Dolomite: Dolomitic Lime contains calcium carbonate, bringing benefits similar to Ag Lime, while also providing magnesium which is important for plants’ utilization of nitrogen, phosphorus and sulfur. Having an excess of magnesium in your soil can cause a break down in soil structure, resulting in hard compact soils. Gypsum: Calcium sulfate, or Sulfate of Lime – CaS042H20, due to its sulfur content Gypsum does not raise the soil PH like lime, and there is some debate as to whether it lowers soil PH. Gypsum helps liberate potash for plant use. Gypsum can also help break up compact and clay filled soils by correcting excess amounts of magnesium in your soil. Oyster Shell Flour: in addition to a large percentage of calcium carbonate, Oyster shell flour contains about 1-% phosphoric acid, which makes oyster shell flour a source of both lime (calcium) and phosphorus. Oyster shell will also slightly raise your soils PH over time. **** From Straw: The horse stable nearby me uses oyster shell lime to deodorize their horse manure. I tested the horse manure pH, and it's over 8. When I applied to my roses, alkaline horse manure (high in calcium & magnesium & potassium & phosphorus) REVERSED blackspots on roses by pumping out new & clean leaves and neutralize the acidity of rain water. Shell lime is best for alkaline clay which needs more phosphorus, plus it raises the pH slowly. Agricultural lime is best to sprinkle on leaves of roses, it's calcium carbonate which is a fungicide, it kills fungus by raising the pH. Dolomitic lime is best for acidic sandy / loamy soil. It will raise the pH, plus supply calcium and magnesium. Magnesium is the "glue" that holds soil together, and is less available in sandy soil. Gypsum also release calcium fast, but doesn't result in pale roses due to 17% sulfur in gypsum. My preference for my alkaline clay: I use shell lime (in horse manure) for heavy-bloomers BEFORE RAIN, and gypsum for wimpy own-roots BEFORE RAIN. Below site sells organic stuff cheap with 5,000 items to choose: 50 lb. of alfalfa pellets for $25, alfalfa seeds, clover seeds (for nitrogen), $9 for 50 lb. of gypsum, $10 for 50lb. of oyster shell lime, $9 for 50 lb. of dolomite lime (best for sandy or loamy soil, since magnesium is the "glue" that retains nutrients). http://www.groworganic.com/search#q=alfalfa hay&p=1 If someone has sandy or loamy soil, the acidic rain will beat up on roots, cause leaching of calcium & magnesium & potassium ... thus leaves become thinner and break out in fungal diseases. I successfully reversed blackspots & mildew on roses just by topping with ALKALINE & HIGH MINERALS & SLOW-RELEASED mulch, such as alfalfa hay (less acidic than alfalfa meal), my dolomitic clay, or horse manure (with oyster shell for calcium & phosphorus for my alkaline clay). Below are some pics. of own-root Golden Celebration. The first one was 2012 pic. in the front of my house, late August 2012: Second pic. below is the base of Golden Celebration, which is 100% clean with horse manure, pic. taken late October 2012 after the 1st frost: Third pic. below is Golden Celebration bloom with horse manure. Golden Cel. got too big for my front walk-way .. when I moved it, there's at least 1 foot of fluffy horse manure, and the root was huge: