I'm new in planting

I have a new box and old box from last year that my husband used for tomatoes, I would like to use both of then for square foot planting, but I am not sure when to start zone 7b and which plants can I put together, any help is thankful.

HI There, you will need to plant based on your average last frost date. Please find that here.

http://www.plantmaps.com/

Also you can use the site http://myfolia.com/ to help determine when to sow your seeds.

Hello fellow Georgian.

I am in Brooks, Ga, about 30 minutes south of the Atlanta airport.  When I first started gardening around here, I used the UGA website a lot to get information.

Here are a few of their publications.  You can search the website and get information about most any vegetable.

This first chart lists the planting dates and recommended cultivars.  This particular chart does not have a footnote at the bottom like some of their other charts.  Another chart has a warning at the bottom of the chart that says

"Note: Planting dates in this chart are approximate for Middle Ga.  North Ga plantings should vary about 2 weeks later in the spring and earlier in the fall.  South Ga plantings can be made 2 weeks earlier in the spring and somewhat later in the fall".

http://www.caes.uga.edu/applications/publications/files/html/C963/C963VegeChart.pdf

http://www.caes.uga.edu/applications/publications/files/html/B577/B577PlantingChart.pdf

http://www.caes.uga.edu/searchresults.html?cx=008984291200700708817%3Anwdzwngdlaa&cof=FORID%3A11&ie=UTF-8&q=Home+Gardening+Planting+Chart&sa=Search&siteurl=www.caes.uga.edu%2Fapplications%2Fpublications%2F&ref=&ss=25991j54990273j54


The planting date also depends on whether you want to cover any vegetables if we get a hard freeze.  If you are willing to cover with some frost protection you can plant even earlier than their chart shows.  I just planted lettuce, broccoli, brussel sprouts, kale, peas, shallots, garlic, onions.  I am a little farther south than you are.
Here is my spring garden just planted last week.  I did have to cover some of the beds to keep some things from freezing.

https://squarefoot.forumotion.com/t17310-2014-sfg-in-brooks-ga#187085

Thank you for all the information, I appreciated. That will help me a lot .