Try the 5-1-1 soil here. It's amazing. It's also cheaper to make then to buy. Most commercial soils are too water retentive.

http://forums2.gardenweb.com/forums/load/contain/msg0214580016564.html?94

Actual soil isn't good for seedlings or any container plants. What we buy should be labelled "mix" rather than "soil."

Al Tapla's 5-1-1 mix -- here's a clickable link -- doesn't contain any soil.
http://forums2.gardenweb.com/forums/load/contain/msg0214580016564.html?94

Yes, Al uses the word "soil." But you'll note that his mix doesn't contain any soil.

All of us have to learn not to use soil -- whether out of the garden or from a bag -- in containers. [BTDT, and nearly everything died.] But let's try to remember to use the right terminology to make it more clear for newbies that soil and containers don't mix.

And that's my pun for 2012.

Supersoil is a potting mix. I think OP is talking about very young tomato seedlings. I would think the root system would not yet be able to handle 5-1-1 due to bark size. Maybe others have experience using it for tiny seedlings? I do put some finebark in when I pot up, but not nearly that much. LInda

Supersoil is not a potting mix even though they claim it is ok for containers. Note they label it as "soil" not "mix" however. It is reported to be Scott's attempt to improve all the problems with their classic Hyponex, which is regularly slammed on gardening forums and has been for years.

You are better off using plain old cheap Jiffy Mix (just be sure to wet it well first since it has no wetting agent) for seed starting than using this stuff. But there are numerous quality seed starting mixes available on the market. Supersoil just isn't one of them.

Dave

You can use 5-1-1 for small seeds, but you have to modify it a bit with a pinch of sand or peat where you lay the seed. This is best if you start in a larger pot.

Personally, I use Pro-mix for seeds in small seedling cells, then transplant to 5-1-1. They seem fairly compatible, and the amount of pro-mix is negligible in comparison to the volume of 5-1-1 after transplant, so doesn't seem to be an issue.

Yes, I agree about the terms. For the most part, we use "garden soil" to denote real soil, and "potting mix" and sometimes "potting soil" to denote soil less mix. Unfortunately, product such as this that do contain actual soil muddy the use of terms, as they should never put out a product with actual soil in it for containers, if this is really what it is.

Several of us had problems this year with damping off in Jiffy Mix. There was a thread about it. In another thread, using diluted chamomile tea to prevent damping off was discussed (with most people saying it worked for them). I had issues with damping off with my flower seedlings in the Jiffy mix, but not so much with the veggies. I did use some chamomile tea once I read about it, but am not sure if it did anything. I looked at this thread because my mother has always liked Supersoil for her indoor potted plants.

Wow. I never knew Supersoil had dirt in it. I used it extensively for potting up all kinds of plants until about ten years ago. As I recall it was always labeled as a potting mix.

For the past several years I've been using Burpee's germination mixes with excellent results. I'm sure I'm paying a premium ordering this stuff on-line, but the up-front expense seems to be paying off. I have zero problems with it. Of course that is probably a signal for them to change ("improve") something and screw things up for me.

Thanks to everyone's comments. I have to tell you that it was my fault and I was blaming the soil. I believe it was transplant shock. The mistake that I made was I potted the seedlings and then put them outside where heat and cold go to them before they could set roots. Some made it ok and are now thriving.

Recently, I repotted 2nd batch and kept them indoors under lights and they are doing fine. I believe the most critical part here is when you repot, keep the seedlings in shaded area away from heat and light for a day or two for roots to set.

Great news that some of the original ones made it. I guess they are the stong ones! Happy gardening! Isnt the weather great here in SoCal?

weather here in So cal sucks right now. for past several weeks its confused the plants and fruit trees like hell. Its warming up nicely now and I hope it keeps it at around mid 80's for plants to thrive.

I live in So.Calif and planted out on 4/2 ... they look fantastic !