Soil pH is a measure of the "potential Hydrogen" in the soil. In soils with low pH there are more free hydrogen ions while in soils with a high pH there are few. If you need to decrease the number of hydrogen ions Calcium Carbonate (CaCo3, lime) has been found to be the best way to do that while adding sulfur will increase the number of hydrogen ion. Rain water typically is acidic and has, over time, lowered the pH of some soils and some bodies of water. Most all municipal water systems add, in addition to Chloramine and Floride, something to make that water close to neutral since water very acidic or alkaline simply does not taste good. Adding Gypsum to soils that are not sodic is usually a waste of time.

@Daninthedirt - I have a couple of Big Beef tomato seedlings in pots right in front of me that say otherwise. Planted seeds at 2" last week & doing fine. The next ones I do will be at 3" and so on. FYI: Co-op Extension often recommends corn be planted at 3" or "down to moisture" in hot dry conditions or sandy oil. Yes I know tomatoes & corn aren't the same animal. Preventing seeds from drying out in drought, hot weather or sandy soils in field conditions calls for planting seeds at maximum possible depth - the question is what is "maximum" depth.

Fox Farm Ocean Forest "potting soil" is primarily a soil-less mix so is what Barrie (and most experienced growers) recommends. It contains only a very small amount of sandy loam mixed in with peat and compost. So it's label calling itself "potting soil" is misleading in many ways. But it does contain some soil Same goes for using compost - it is NOT soil unless one adds soil to it. Most products labeled "potting soil" are made up of dirt (top soil) with a few other non-soil additives mixed in and should be avoided for seed starting and use in containers. Pays to keep in mind that what one calls "best results" would be another's "poor results" so one can only evaluate results by trying both approaches before committing. Decades of experience has proven repeatedly that potting soils for seed starting and container growing leave a great deal to be desired in germination rates, growth rates, and drainage issues - thus all the mixed reviews FF gets. As for using 8" pots for germination vs. shallow cell packs/trays? Those problems are also well documented in the industry. Would you start your young child out in the kiddie pool and gradually move him into the shallow end of the big pool or just throw him in the deep end and expect him to do well? ;-) Dave PS: "Peaty mixes tend to dry out pretty evenly IME - meaning if the surface is dry it’s pretty dry throughout." Sorry but that isn't my experience. The surface tension, temperature, air exposure, and evaporative rate on the surface is substantially higher than it is even 1/2" down.

Wow, very interesting everyone on all your views and what you all do. As for me I will answer my own questions too in the hopes it will help others also) I was wondering if many here uses rain water and consider it a very important to the success to your orchids? Yes, I do and when I do the roots always look more vibrant and healthy. When I use tap, it discolors my pots, roots to my orchids and seems to make many of the tips of my plants turn brown. Take for instant 'ptothos'. I can't use tap water. I can't use my tap water on my palms, carnivorous plants, ferns and mosses along with all of my orchids. How do you collect it? I collect water in a 30 gallon bucket from my roof from a roof gutter that pours it straight into it. Then I use a hose and sifon all the water I collect into my 30 gallon buckets in my basement. 6 to be exact. Enough to last me thorugh the whole year when I keep refilling. I do use tap water for all outside plants and baskets. Do you use bottled water? Not for plants , just for humidifer use along with bottled water. Tap water would destroy my machines. Do you use tap? Only for outdoor plants, and to flush out my orchids, which I will come right behind when I have time and rinse with rain water. Do you flush your orchid pots and how often? Yes, once a week at least. The roots always fatten up and turn a rich green . When I just water or use a sprayer, the roots seem to stay partially dehydrated anyways. Why do you you use rain water? It's cleaner, very low TDS (2ppm). Rainwater also contains a little nitrogen. Do you SOAK your orchids or just water them in? Both) Do you feel it's important to spray your orchids and why? I do this to wet everything near where my orchids sit, and top moisten the top layer of many of them while the bottom still dries out. It's easier for me to do this with mounted ones. those I can't reach in the green house, and to keep the spider mites in check and leaves clean. Do you use a humidifier? A BIG FAT yes!! I don't use one in my greenhouse or my sunroom that does not have a heating system in there. I do use one in my sunny warm heated room uspstairs where I sleep and where all my plants reside of the air in there would be bone dry and warm. Do you measure the moisture in the growin room? I use a standard humidity/temp meter. I have to know how much humidity I have in there to make sure there is not too much to prevent mold issues and too little to prevent plant issues. So I adjust my humdifier accordingly. Thansks for all the feedabck. I had no idea about water and the issues they can prevent like explained above. I wish I could afford to use a RO machine or I would do that too. Thanks everyone.