It might be nice to get some bedding plants so they don't have to wait
I'll ditto that! I was going to suggest that too. Since clearly they
were excited, they want it to be successful, so make sure that there is
something beautiful and growing in there, even if their own ventures
don't succeed from seed. Every time we've gone to the plant nursery
over the years, the kids always pick something to plant because they get
excited about it, just like I do.
We still have a beautiful (even if it is really little) ground cover
garden that Chamille planted over 3 yrs ago!