Thinned out some sprouts and started hardening off by putting the tray outside in the shade during the day. Do not try to harden off by putting indoor sprouts in full sun all at once. It will kill them.
I've ferted twice. Once with some Burpee brand no nitrogen organic fert derived from kelp when I sewed the seed and once with Lady Bug Brand John's Recipe once everything was up. Lady Bug has nitrogen.