Both oceanForest and worm castings are chemically 'hot'. I's frankly surprised that seedlings even survived in that mix!
And personally I would have added even more perlite, but as long as you drain okay...
Well cool. Try a foliar. Just FYI since your mix is going to retain water, any pH issues you may have will be more pronounced. Cold, wet soils make 'off' pH symptoms MUCH worse. So keep an eye on that, and make sure you allow your soil to become rather dry between waterings.