Great news! You can sign up for the Home Depot Newsletter and be the first to receive emails about special offers, coupons, and promotions from The Home Depot. You'll also have the opportunity to join the "Garden Club" and get some exclusive coupons in your email! I just received some coupons the other day for "Buy one bag of bulbs, get one Free" and "Save $3 and $5 on Fertilizer". I believe the Garden Club also lets you get expert advice (via email or a forum) from gardeners-- something I would definitely need!
(PS: Lowe's usually accepts Home Depot coupons as well!)
UPDATE: Fixed the link- sorry about that!