There is one piece of information that affects everything about your garden. From when you start seeds, to when you plant outdoors, to when you buy seeds, to even what varieties you can grow where you live. Take a guess.
Wrong! Its not your growing zone! 6a ,4b, 3c... They may be helpful for flowers, but not food. Starting right now, I want you to forget your growing zone and replace it with your last frost date.
A hard frost, or killing frost, occurs when temps dip to 28 degrees for more than a few hours. Warm season vegetables like melons, tomatoes, peppers, eggplants and squash become damaged at this level. Your last frost date indicates, with 90% confidence, that no more hard frosts are expected to occur. That means it is safe to plant and transplant outdoors.
Your date is related to your very specific location based on year and years of historical weather data. In Tennessee, Memphis has a LFD of March 27 and Erwin is April 25. The point being they are in the same 'growing zone' but have huge variation in climate.
So your LFD tells you when its generally safe to plant outdoors. If you are growing peppers, tomatoes or eggplants, subtract two months to let you know when its time to start your seeds indoors.
Your first frost date is when the first frost comes. So the number of days between your last frost and first frost is your growing season. This is the number of days you have to grow...
Its the key to gardening and now you know.