I can see the beginning of what looks like a deficiency but it's no cause for panic, especially when you have organic, to back you up and give you luck in case of difficulties on the road to success. But If you're asking is it safe to foliar feed with the fert you are using you haven't done your homework, that being said, I am aware you did not pre-charge your coco, that is not a disaster either, your plant will adjust but it will take time. I do not know of ANY non-organic fert that is made for foliar; chemical products in general are not!
Yes, you can (and should) foliar feed, that is a tonic straight to the heart of any problems you have, it's quick, easy and often very effective, now, what to do, what to do?? There is the question, the answers are many and varied, more to come...