Is it normal for coco to go a kind of a light brow...

mate,good luck for your first grow,very good decision to start with coco.I'm also trying the coco for the first time,I've grown in soil before and made some searches on internet about coco,trying it now and LOVED IT! Coco is really the way to go.But,I was always told that coco needs to be fertilized each watering.Because it doesnt contain any nutrients unlike soil.You got your own answer to this question ; ",will start feeding on the 8th day," . you should start feeding from day 1 in coco.that's why they are indeed small for a week old plant.They look green and healthy but if you don't start feeding soon, you'll see those first ever single leaves getting yellow meaning plant eating itself.Feed it and watch how it thrives. Other question,coco being brown around the edges.It is normal,means that part is dry.Only water there you think their roots reached in the pot.outer parts are still empty,no roots there,no need to spill water there.Dry coco looks light brown,yours is just dry around the edges,pretty normal.