It's all I ever use,never had a problem with it.You will be fine.
cAROL

I used MGMC last year because it was all I could get but I blended it with seed starting mix & Perlite to improve drainage and used a measured amount of water to wet the soil in the jugs prior to sowing. I had spectacular germination altho' the containers stayed really wet right up until the end of May. WS sprouts are tough and they didn't appear to be affected or bothered by the soggy condition of the soil in the jugs. It's possibly not the best medium to use but you should be okay.

I used it year before last because it was all I could get. I will not use it again. The mix stayed too wet and I had some seeds rot, even with adequate ventillation and drainage holes.

I bought some this summer from BJ's and got a little freaked out when I saw mushrooms growing with my houseplants. Being wintersown seeds need moisture I would think it would be good.

I am currently using MG Potting soil, and Pro-mix if I can find it.

I do use good drainage, so that may be why I have never had a problem using it.
We don't have Pro-mix around here,I would love to try it one day,but for me, so far, this is working,maybe you can try both, see which works best for you.
I just would never use garden soil.
cAROL

I've used it, no problem here as long as the flats have good drainage. My flats are usually in a partially shaded location, but if they were all out in full sun all day long then I would use it all of the time.

I mixed water into the Homer Bucket and stirred it up good (I remembered somebody said "like brownie batter" and it didn't seem that moist so I would add some more once I got the soil in the milk jug and let it drain before I planted my seeds..Eileen, I have seed starting mix that I can add to what little bit I have left. Gosh, all that work, I pray that none of my seeds rot. Oh well, a good lesson learned so hope all is not lost.

Thanks to all who responded.

It's all I use. My jugs are under an overhang and don't get rained on, so I have to water some, and I use the Moisture Plus soil to cut down on that. I also use it in my porch pots because of our hot summers. I have never had an issue with the soil staying overly wet or being soggy. Could this be caused in some cases by bottom watering and letting them stand in water? My experience is that this type of potting mix drains water out the bottom holes when you water it (or it rains) about as fast as any other, but it retains more even moisture for longer due to the granules. The water just doesn't seem to evaporate out as quick as with regular potting soil. I would not worry about rotting so long as you have good drainage.