Probably not a complete list, but these are festivals throughout Ohio that relate to things we can grow in our garden/orchard/etc. They are in order according to month. I have marked the ones that are closeish (an hour or less from Center of Columbus according to Google) to central Ohio.

more festivals: http://www.ofea.org/events.php?listby=month&Submit=Go

Newark Strawberry Festival
June 1 – 3, 2012
www.newarkstrawberryfestival.com

London Strawberry Festival
June 21 – 23, 2012
www.londonstrawberryfestival.com

North Ridgeville Corn Festival
August 10 – 12, 2012
www.nrcornfest.org

Lexington Blueberry Festival
August 16 – 19, 2012
www.lexblueberryfest.com

Renyoldsburg Tomato Festival
AUG. 17-18 012
http://reynoldsburgtomatofestival.org/about2012.html

Obetz Zucchini Festival
August 23 – 26, 2012
www.obetzzucchinifest.com

Ohio Tobacco Festival in Ripley
August 23 – 26, 2012
e-mail: jfauth@dragonbbs.com

Sweet Corn Festival, Inc. in Millersport
August 29 – September 1, 2012
www.sweetcornfest.com

Milan Melon Festival
September 1 – 3, 2012
www.accnorwalk.com/MelonFestival/

Marion Popcorn Festival
September 6 – 8, 2012
www.popcornfestival.com

Mantua Potato Festival
September 7 – 9, 2012
330-274-0770

Johhny Appleseed Festival in Lisbon
September 15 – 16, 2012
www.lisbonareachamber.com

Ohio Paw Paw Festival in Albany
September 14-16, 2012
http://www.ohiopawpawfest.com/

Old Time Farming Festival in Centerburg
Always the Third Weekend In September
http://www.oldtimefarmingfestival.org/

Jackson Co. Apple Festival
September 18 – 22, 2012
www.jacksonapplefestival.com/

Barnesville Pumpkin Festival
September 27 – 30, 2012
www.barnesvillepumpkinfestival.com

Geneva Area Grape Jamboree
September 29 – 30, 2012
www.grapejamboree.com

Ohio Gourd Show in Greenville
September 29 – 30, 2012
www.ohiogourdsociety.com

Oak Harbor Apple Festival
October 13 – 14, 2012
www.oakharborohio.net

Circleville Pumpkin Show
October 17 – 20, 2012
www.pumpkinshow.com