Mixing topsoil with the seed starting mix is a bad idea. The whole point of a seed starting mix is that it's sterile. Adding topsoil would negate that benefit. Not to mention that topsoil isn't meant to be used in containers to begin with. Seed mix is supposed to be used until the seeds sprout. From about the time the seedlings reach the true leaf stage it's beneficial to transplant them into a regular potting mix that has some fertilizer added.

Rodney

FWIW, it's pretty easy to sterilize soil. I do starts with a mix of good soil and peat moss and, while it isn't optimal, it's really cheap and it works OK. But I *always* sterilize the mix. The idea that seed mix needs to be used until seeds sprout doesn't make a lot of sense to those who swear by direct sowing (which I don't). That is, anything you can sow directly sure doesn't need to be started in seed mix. Makes some sense to use a bit of soil to help retain water.

Not sure if there was a question posed by the OP, but if it was whether a bit of soil would hurt anything in a starting medium, I'd say no, as long as it was sterile.

Agree with Rodney. There is seed starting mix and then there is growing mix. Two separate things but both are soil-less mixes. Growing in containers normally means no soil. It compacts. It causes drainage problems. Growing in containers and doing it indoors, under a grow light is no place for soil (dirt) sterile or otherwise.

Indoors under a grow light everything dries out quicker than it does outside. It is a normal part of the totally different process so you adjust your watering regimen, your humidity, your air temp, and your container size accordingly. But adding dirt to the mix doesn't solve that problem and only creates other problems.

Dave

Top soil is not good for indoor growing, even sterilized. 2 parts of coco-fiber or peat moth, 2 parts of good compost, 1 part of perlite, 1 part of vermiculite and slow release fertilizer works for me. You also can use shredded pine bark as your first ingredient.

I think that adding perlite and/or vermiculite would be helpful as would using a room humidifier and watering from the bottom.

There are several forums that may be more helpful... See also the related forums listed in this link and the FAQs. http://forums2.gardenweb.com/forums/seed

I respect the comments about not using dirt in starting mix, and I'll agree that it isn't optimal, but I'll say it again, I use it, and it actually works pretty well for me. I should correct myself and say that I use a mixture of sand, peat moss, compost and soil. Soil is maybe 20% of the mix. The sand ensures good drainage.

I don't use ground dirt in seeding mix simply because I found a method that works extremely reliably for me, but otherwise I'd have no problem using it except for two caveats. One is Dan's warning to nuke the stuff first; surely take that to heart. Secondly, so much of the success in this depends on all the other points in one's starting methods that adding dirt could quite possibly be terrible.

Maybe putting your plants starts over (not in) a water bath (a tray with water and a grill/rack/screen arrangement) might help with excessive drying without changing your starting mix. It's often effective in arid atmospheres like ours but I'd think your zone wouldn't have a humidity problem. Watering problems aren't often medium problems; they're usually fixed by adjusting the grower's habits.

Depending on the number of seedlings to manage, and your ability to attend to them, I find humidity domes very helpful for keeping the medium from drying out. Some even have vents to adjust the moisture/humidity levels. Leaving them unattended though, can cause a problem opposite of drying out... damping off. Balance and care, balance and care.

I do only use soiless mixes, and I have put a fertilized container-appropriate grow mix in bottom of the container, then cover that with the seed starter mix. The idea is to allow the seed to germinate in the seed starter, then for the roots to soon find the fertilized grow mix below. It allows me to skip a transplant step for those crops which prefer not to be disturbed. I usually use cells, but when I do the 'half-and-half', I use a larger (2" - 4" or so) container.

For me, it's about doing it right versus doing what works. There's a lot of that going around!

I use regular potting mix for seed starting and to fill grow bags. I even reuse the contents from the grow bags. mix with new mix and add fertilizer. It may not be the right way, but it works and saves money.