How much light do you have them under? If they're thin and lanky, they're probably stretching and not getting enough light.

I used several different seed starting mixes this year, including some miracle gro when I couldn't find anything else. The miracle gro seed starter seemed to hold too much moisture for my tomatoes. The ones in jiffy mix seemed happier.

I'm trying to boycott monsanto products this year, so been actively avoiding miracle gro since it's owned by them. However, I used MG potting mix extensively in the past and always had good results.

The plants from your local Wallyworld have been grow in temperatures much cooler than inside your hoome where you start and grow your seedlings . In colder weather the stalk tend to thicken up .

I start my seeds under lights in the unfinished part of my basement, which stays in the low 60's. My seedlings are always a little leggy, I think because my lights are a little weak. It doesn't matter, I plant them deep & once outside in my garden they thrive and quickly catch up to any store bought plant.

Weak light dont help
Also need to keep light within 2 inches of light

busboss - you might want to go over to the Growing from Seed forum and read the how-to FAQs there. Lots of information on how to do it. Plus I linked the How to Grow Tomatoes from Seed FAQ below for you.

Is MG the best? No but it can be used and many do with no problems. Is MG good for transplanting them into? Not the best again but it's ok and many use it.

So if your plants aren't growing well after you transplant them into it then there is some other cause for the problem and we need more information.

As others have mentioned, lots of supplemental lighting and cool growing temps is what gives you strong stems but you can't really expect plants that look like the commercially grown plants since they are grown in greenhouses with all sorts of expensive environmental controls.

Impossible to duplicate that unless you have a greenhouse too and want to invest lots of money in it. How do I know this? Because I have ghs and grow plants for sale. But that doesn't mean you can't grow great tomato transplants in your own home.

I can also tell you that the most common cause of problems with poor growth is over-watering. it causes the roots to rot due to lack of oxygen. Next biggest cause - too small a container.

Hope this helps.

Dave

A lot of good advice, and I would echo that bigger is not better. The main thing is to get them outside as soon as possible and not start them too early. Last year I picked up a pop up greenhouse at Lowes this time of year that was on clearance. It was regularly around 70 and I picked it up for 25. I started my seeds the third week of March and as soon as they popped I moved them out. It was a very cool Spring and I had to watch the weather very closely for temp, wind, clouds, and sun and adjust the doors accordingly, since I wasn't home during the day. I repotted in MG in 4 inch pots. If the temp dipped below 40 overnight I brought them in, but put them back out the next morning. A couple of days I left them inside until I returned in the afternoon, but not under any lights.I started planting out the first week of May. Anyway long story short they ended up bigger than I prefer and were somewhat root bound but they had very thick stems, 12"-18 "and lateral branches all the way down to the bottom.

You will get better results using a potting MIX not planting soil when repotting seedlings. Regardless of which brand you use.

I was having major problems last year; most of my seeds wouldn't sprout, even though of several varieties. Then I read on some gardening forum that people were quite unhappy with MG seed starter. It was the first time I'd used it.

When I switched to a different brand of seed starter, my success rate went back up to what I would have expected. It was good that I had the time and the extra seeds to try again.

The MG seed starter had quickly settled to half it's volume; I'm guessing it ended up being too dense for the tender sprouts to push up through it.

I used MG seed starting mix and had very good germination, I would guess 80-90%, but I did add a temperature regulator to my mat this year and I think it helped. I had used Jiffy in the past and never had any real problems with that either.