Your card will be charged the Sunday before your scheduled delivery date.
Prior to Sunday's charge, you may see an authorization on your account on Wednesday. This is a temporary authorization hold, not a charge.
Just like many other merchants, Purple Carrot uses an authorization hold to confirm your payment method. The authorization holds are removed by your card company and your card is never actually charged.
On Sunday, Purple Carrot immediately releases the hold when charging your card for the full amount.