Too early for CO2?

Hey everyone,

I've been growing some seedlings on a windowsill (will move outside once they are big enough) for around 5 days now. Two plants have sprouted and now have 2 round leaves and 2 pointy leaves. Are these plants too young to supplement with carbon dioxide? I was planning on just spraying with seltzer water (don't have much cash).

Thanks ... ... Stay high ...