Think there’s no such thing as too much tomato? You can put that theory to taste Saturday when the area’s two big annual tomato festivals go head to head. The Hanover Tomato Festival is up first, kicking off its 31st year when the gates open at 9 a.m. at Pole Green Park. Two hours later, the 11th annual Shockoe Tomato Festival takes over Richmond’s 17th Street Farmers’ Market.