The first picture represents the Gardening calendar I reference. I consider my area Zone 6, overlapping Zone 7, so I would directly sow Kale, Lettuce, Spinach, Peas, Carrots, and Beets at the beginning to middle of March. Around this time I would start Cabbage, Brussels, Cauliflower, and Celery, indoors to transplant in April. In April, I transplant Celery, Brussels, Cabbage, and Cauliflower as well as grow a second crop of greens. At the beginning or middle of March, I start Tomatoes, Peppers, and Melons indoors indoors to transplant in May. At the beginning of May, transplant the Tomatoes, Peppers, and Melons as well as directly sow Squash, Corn, and Beans.
This sounds like a simple garden, but in fact I'm growing much more than this. I am only explaining what you see in the calendar below. The calendar isn't a representation of all the vegetables, herbs, greens, and Fruit trees I'm planting. The post, Seeds I bought for 2015 Garden, will give you representation of my seed inventory which I will be growing this year.
The following pictures represent all USDA Gardening Zones First and Last Freeze dates, as well as planting dates for each vegetable.
photo source: Veggie Harvest
photo source: Grow it Vegetable Gardening
The Farmers Almanac also provides you with a garden calendar for growing different vegetables by Moon Phases (in the United States), which you can view here: Planting by the Moon Phases Garden calendar.
I usually cannot grow by the Moon phases, because of heavy rainfall during April. You always need a couple of days of nice weather to plant many of your vegetables. But out of desperation, I have planted in the rain before.
In the past, it took my several days of nice weather to plant because I would need to till the soil for our 3 1/2 gardens. In hindsight, tilling and hoeing up rows took up most of my time. Now, I plan to AVOID tilling and hoeing rows because I'm implementing Permaculture techniques. Permaculture design is a layering system as seen in the Forests. For example, I will be growing vegetables in layers of mulch and compost instead of tilling and hoeing. This is a much easier system, as well as more nutrient dense. If you haven't seen the information I have provided on Permaculture, go to my post here: No money, work, tilling: Permaculture.