I have sown packets of seeds that were 3 or 4 years old and they germinated and grew fine.
For baskets, you could sow now as long as your baskets are protected from frost. I see you're in PA so you will probably have a lot more frost coming. I always surface sow and don't cover. Because the seeds are so tiny, I direct sow wherever I want them, whether in the ground or in baskets.
Can't wait to see your photo's when they are blooming
