Ohio sits across USDA zones 5b and 6b, which means the last spring frost lands somewhere between April 20 and May 15 depending on how far south you are. Tomatoes set out before that date will sulk at best.
When to plant
Start seed indoors six to eight weeks before your last frost date. For most of the state that means mid-March. Transplant when night temperatures hold above 50°F — soil below that stalls root growth even when the afternoons feel warm.
Varieties that finish in an Ohio season
Look for anything rated under 80 days. Early Girl (57 days), Celebrity (70) and Big Beef (73) all ripen comfortably. Long-season beefsteaks are a gamble north of Columbus.
Watering
One inch per week, delivered in one or two deep soakings rather than daily sips. Irregular water is what splits fruit and causes blossom end rot — more often than a calcium deficiency does.
The local complication
Late blight arrives in humid Ohio summers. Space plants 24 to 36 inches apart, water at the base, and pull lower leaves as the plant grows so air moves through.