Absolutely coat the ends as soon as it hits the ground. Nothing I've used works as good as shellac. As you split it up and one coat dries, add more coats. Then when you get home, add a few more coats.
Another tip is to cut your staves loonnnggg. That will give you more wiggle room to lop off any checks that do develop later, and to pick the stave section that is best for a bow.