i would up-pot them into bigger container. at least give it a bit more room for the roots? maybe 1gal pot? even if it its a shorter plant (are autoflower ones shorter?) ive not done autoflowering, so i cant strictly speak. But basic botany, blood meal is just a natural source of Nitrogen, and its not going to give a nute taste to your plant. Just dont over do it. I dont know if bone meal is good in containers. Ive tried it with mixed if any results. Think I saw sumwhere here on RIU about it not being that effective in some type of containers, maybe that meant soil only, or other substrates such as hydroton or coco, etc. The stuff is just super chunky and really gotta stir/mix it up, otherwise it just doesnt saturate really into the medium and just stays on top a lot.