Marie,

I'll take a stab at a couple of your questions.

"Container Soils - Water Movement & Retention XIII"

1) This is the parent thread for the "gritty mixes" (both 5-1-1 and 1-1-1). It has reached the maximum allowable limit of 150 posts 12 times, so there is a vast amount of information in the 13 different threads.
Near the end of Al's first post, the 5-1-1 ingredients are described.
As I understand it, the 5-1-1 mix is used for plants that will be repotted frequently (2 or 3 years max (from Al's first post in the above linked thread)). Although, in the back of my mind, I seem to think I've read in a post suggesting the 5-1-1 mix really should only be used for 1 or 2 years.
2)When screened properly, the 1-1-1 mix is very free draining, has only one part organic matter (screened bark, nothing smaller than 1/16" in the 1-1-1 mix) and from Al's first post in the above linked thread "For long term (especially woody) plantings and houseplants, I use a superb soil that is extremely durable and structurally sound. The basic mix is equal parts of pine bark, Turface, and crushed granite."

3)Yes on ingredients and ratios. From some of Al's other posts the lime brings the pH of the 5-1-1 mix up from around 5 to around 6. It also serves as a source for calcium and magnesium. If you are growing plants that like acidic soils, you can replace the lime with gypsum and add epsom salts to your irrigation water.
"Fertilizer Program for Containerized Plants III" should give you all the information you need for dyna-grow foliage pro, pro-tek, etc and when and why to use gypsum vs lime.

4) Although I haven't used the gritty mixes for seedlings, I think I would start seedlings in the 5-1-1 and move to the 1-1-1 when ready unless the seedlings were annuals or a plant that needed frequent repottings. That being said, I'm pretty sure I've read that seedlings can be started in the gritty mix and left in the gritty for the life of the plant. I think the only caveat to starting seedlings in the gritty mix is not to use the "chop stick method" for measuring soil moisture, instead ensuring the upper couple of inches of the soils is always moist, so the young shallow roots don't dry out.

I'm no expert by a long shot. I've just spent many hours reading and trying to absorb information. So, if I've posted erroneous information, I'm sure the very helpfull people here will correct my mistakes.

Hope this helps.

Blake

Thanks, Blake. It;s time to re-read those articles. Appreciate the links.
mt