Planting more tomatoes

Tonight I planted a few more tomato seeds.  I think I am still a bit early but I have lots of seeds so its better to have too many plants come spring then not enough.  At this point I am thinking about building a greenhouse but who knows if it will happen in time.
I planted :

• 3 Golden Girl -germinated March 20
• 3 Roma VF -germinated March 20
• 4 Sugary F1 Hybrid - germinated March 22
• 4 Sungella- germinated March 21

One seed of the Sugary F1 Hybrid that I planted last weekend has germinated.  It does not look healthy I am thinking they got hit by damping off.  I have been putting the trays inside of ziplock bags.  Looks like I need to get some air circulating and get some fungicide.