Most of your commercial seed starting mediums contain slight traces of fertilizers especially ment to get seeds/seedlings off to a good start. To have a truly "organic" blend, you'll have to make it yourself. Here's a basic peat starting mix for you: 2 parts coconut coir or peat moss; 1 part vermiculite; 1 part perlite, 1 part dehydrated steer manure; and 1/5 part dolomite lime. The lime is used to raise the pH of the naturally acidic peat, also provides calcium and magnesium, Espoma brand of pelleted is excellant! To prepare the blend, start with the peat and dampen thoroughly. Add next ingredient, mix, dampen and blend again, continue til you have it all together in the amount you need. It is highly advisable to wear a mask when making the medium to avoid inhalation of dust(s) associated with perlite and lime (if a powdered form is used). Making your own will not be cheap: think you'll find costs of everything, overall, will be very close to purchasing something already made up.
If you want to try a commercial blend that contains micorise (helps in root formation), a 16 quart bag of Pro Mix Ultimate Seeding Mix can be gotten thru www.greenhousemegastore.com for $12.95 plus $5 s/h. This is the BEST I've used yet, and you can't find it everywhere! Item number is: SO-PM-USM so you can find it faster if you want to look at its contents.
Hope I've helped a bit...GOOD GROWING!

Plain old Jiffy Mix has nothing but peat and vermiculite in it. Check out the previous discussion linked below - many tips in it. Plain old peat plus vermiculite or perlite is about as "organic" as you can get. ;)

But I'm surprised you couldn't find one online - Gardeners Supply, Gardens Alive, Parks, Gurney's, etc. all carry various types. metro Mix is organic as all it has added is a wetting agent.

Dave

Or just use homemade compost - many discussions here at GW about it (see link at top of the forum page called Peat vs. compost.

Here is a link that might be useful: Best seed starting mixes