With germinating should you wait until the tap roo...

As soon as you can see it, plant it. Waiting for it to grow any length increases the risk (extremely) of causing damage to the vital and fragile/delicate root tip that determines exactly how well your plant will grow, as this is the very beginning of "embryonic" growth. I agree entirely with what the others have written, much better to use a cube/jiffy/plug etc that you can germinate the seed in and avoid handling the delicate sprout when planting the cube/jiffy/plug, rather than trying to position and bury the embryonic seedling. This way the root is also going straight down from birth, instead of sideways and having to change direction when planted, as this uses vital energy the seed could better utilise for growing. Hope this helps, Organoman. P.S - also yes, remove any type of cover as soon as the seedling breaks the surface, it will need air exchange and does not need excess humidity which can cause "damping off", whereby the stem rots from the excess humidity. Only clones require amplified humidity when first taken, due obviously to not having any roots for the first few days.