It can be a little difficult to distinguish toxicity from deficiency but the classic telltale sign for toxicity is burnt tips. Is there anything you did that would indicate you overfed or underfed them? If you're growing in organic soil, there should be plenty of nutrients in there for a young plant for a while, at least 2 months of veg for most commercial soils and they're the kind of nutrients that shouldn't burn your plants if there's excess in the soil. Most of the time new growers run into problems either with poor watering practices or screwing with the pH of their water. Someone else on this forum says it all the time, "We kill them with love."

If you are worried they could be deficient but you also don't want to nute dump on them, you could do a light feeding of fish emulsion or kelp. They're both organic and low risk for toxic accumulation. Or, water with a compost tea.