depends on how big they are or small and what they are made up of?
and how large your population is on things that will eat them on you
High deer numbers? can mow a small plot fast
its hard to say not knowing all the details

deer will find NEW food fast, if other foods are not so easy or close by
like I said a lot of variable's

a week before season will get them in it IMO
but do you want to save them for the rut, or??