One of the best resources I've come across recently: Krank Press' perpetual produce calendars for gardeners and chefs alike. Available by region (Bay Area, Texas, Desert Southwest, New England, etc.), each month the calendar offers two lists: what to plant and what is in season for eating.
Above: A linoleum block print of a seasonal fruit or vegetable adorns each month of Krank Press' calendars. Shown is the February page in the Bay Area Produce Calendar. The calendar is not year-specific, so you can keep using it for years to come; $20 each through Krank Press' Etsy shop. It is also available through Fire Escape Farms.
Above: Letterpress printed in three colors on heavyweight recycled card stock and wire-bound with a metal hanger, Krank Press' perpetual produce calendars measure 5.5 by 8.5 inches (thinking this is small enough to pluck off the wall and accompany me to the farmer's market). Shown is the New England Produce Calendar.
Above: The days of the month have space for notes well suited for recording what you've planted, harvested, or purchased that month.
Above: A page from the interior of the MidWest Produce Calendar; $20 at Krank Press Etsy Shop.
For more planting gift ideas, see "Gift Guide for the Armchair Farmer".