Do not buy seed, even if it says "organic" at your local home improvement shop, because it can still be GMO, even if it is claimed to be organic.
Here is a list of websites that sell non-GMO guaranteed seed. I personally buy from High Mowing Seeds and Natural Gardening Company. I also bought medicinaly herbs this year from Mountain Rose Herbs. Everything has produced seedlings under growing lights (even 2 year old seed from last year) and I can have the peace of mind that I am feeding my family the very best out there.