i have never had an luck getting the "real" pro mix. I buy "growers mix" by Fafard at about $20.00 a bale( its pretty much peat) and add more vermiculite/perlite and I have great results.
MG is ok for potting up but every thing that has the Mositure control in it is TOO wet and the seeds rot

bookjunky - if you want to email the ingredients listed on the pro mix bag I'll compare it to the ingredients listed on my Fafard growers mix bale & let you know if they match. I picked up 3 bales a few weeks ago, dropped one off at my daughter's* and the other two are inside my garage.

* She decided to WS last year but she fought using growers mix (instead of her own garden dirt) tooth & nail to the very bitter end. I gave her the bale of Fafard as an early Christmas present.

I've used Fafard, good stuff.

Karen

I can't get the Pro-Mix bales locally anymore either. The organic Pro-Mix is what I used last year and I got it at Menards too. It is good stuff, very good germination, drains well, and easy to work with.

Only issue I had was that I was very delayed in planting out due to weather. The seedlings were getting quite big and then seemed be suffering, but perked up after I started fertilizing them until I could get them planted out. I think maybe because this mix uses organic fertilizers they don't last very long. Most of the other potting mixes like Miracle Grow have time release non-organic fertilizer pellets in them that kick in once the weather warms up and last a few months. I can't be sure if lack of nutrients was the issue because the weather was pretty weird too. It is just something to keep in mind with a mix like this.

Bookjunky, a 3.8 cubic foot bale of Pro-mix BX is going to cost me $35.99 at the local Ace hardware. They are ordering it from the warehouse which is going to be delivered next week. 1 cubic foot for $5.00 is a good price for potting mix. The Pro-mix Ultimate Organic contains compost (about 25%) which is a cheaper ingredient however, whereas the Pro-mix BX is pure peat, perlite, and amendments.

Any mix in a container that contains compost, topsoil, or garden soil will compact sooner in the container than a "soilless" potting mix. This may or may not end up being a problem for winter-sowing, where the seedlings are not usually in the container for more than a few months.

The Promix ultimate organic will probably work great. If you can find one of the large bales I would still go with that though.

Anyway, Gardenweed, what kind of results did your daughter have using garden soil for winter-sowing??

terrene - my daughter's first comment about winter sowing was, "But Mom, the seeds can't breathe under all that snow!"

She has a beautiful garden and grows vegetables every year by direct sowing seed in her garden bed so she questioned why it was better to use potting mix in place of regular garden dirt. I just told her to go ahead and use it if she didn't care what results she'd get. I gave her all those answers right off the WS FAQs page.

Gardenweed - if she really wants to know why soilless or even a gritty mix is best for containers, have her read one of Al's treatises from the Container Gardening forum.

Here is a link that might be useful: Container Soils - Water Movement & Retention X

Okay, here is what I ended up getting at my local Menards http://www.menards.com/main/lawn-garden/lawn-care/pro-mix-reg-outdoor-planting-mix/p-1509489-c-10116.htm. I can't find list of ingredients online, but if I recall its compost, spaghum peat, and some other amendements but no perlite/vermiculite. It was spongy when I pressed on the bag like the big bale I used last year. I'm thinking I should mix some perlite in with it. They only had one bag of the organic left and it was torn. I got them on sale for $4 per cu. ft. bag!

Booklife, I'm not familiar with the different ProMix formulas, they aren't available here. But - The description on the page you linked says '�Ideal for amending low nutrient and poor soils'....it doesn't say it's formulated for containers. Does it read that specifically on the bag someplace, that one of its uses is for containers?

I am up to 14 1 cubic ft bags of Promix and half of a 2 cubit foot bale of something call Ball professional growers mix (my FIL uses it at the greenhouse and they were throwing the extra out). That might be enough to get me through this year's WSing.