There is absolutely nothing in your soil besides peat moss, sphagnum, and perlite? No dolomite? No fertilizer? Are you certain?
Most seed banks recommend nothing for the first 2-3 weeks if growing in soil. Though after you have some experience, you learn what can be safely added early.
If its your first grow, I'd give it only water for the first 3 weeks, then introduce it to nutes on day 21. The "Lucas Ratio" is probably the cheapest, safest approach to nutes (use half strength in soil).
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