Lettuce is a cool-season crop that requires careful timing in Ohio, where spring quickly shifts to summer heat. This leafy green thrives in a narrow temperature window. Planting too late causes premature bolting, and late spring frosts can damage young plants. Precise planting dates ensure a tender harvest before summer arrives.
Understanding Ohio’s Critical Planting Dates
The planting window is defined by the average last spring frost and the arrival of consistent warmth. The average last frost date guides planting, falling between mid-April in southern Ohio and early May in northern regions. Gardeners in the Cincinnati area can typically start earlier than those near Cleveland.
Lettuce grows best when air temperatures remain between 55°F and 65°F. High temperatures trigger bolting, causing the plant to send up a flower stalk and the leaves to turn bitter. Planting too early risks exposure to a hard freeze, which can kill young seedlings. The average first fall frost, typically in October, signals the end of the second growing season.
Spring Planting: Techniques and Varieties
Gardeners can maximize the spring harvest using two methods: starting seeds indoors or direct-sowing outdoors. Starting seeds indoors four to six weeks before the last expected frost provides a head start. Seedlings must be gradually exposed to outdoor conditions, known as hardening off, before being transplanted.
Direct sowing is suitable once the soil is workable and has warmed to at least 40°F. Optimal germination occurs between 40°F and 75°F. Loose-leaf and butterhead varieties are the best choices for the unpredictable Ohio spring due to their faster maturity and stress tolerance. Dependable selections include Black Seeded Simpson and Buttercrunch Bibb, which handle cooler soil well. Transplants can be set out three to four weeks before the last frost, as hardened lettuce withstands light freezing temperatures.
Strategies for Continuous Harvest
To extend the harvest beyond spring, employ succession planting by staggering small sowings over time. Planting a new batch of seeds every ten to fourteen days ensures a continuous supply of young, tender leaves. This technique is effective until the weather consistently warms above the optimal range for lettuce growth.
The primary challenge in Ohio is mitigating summer heat, which causes bolting and bitterness. Providing afternoon shade is an effective strategy. This can be achieved by planting lettuce on the east side of taller crops like tomatoes or using a physical shade cloth to filter midday sun. For a late-season harvest, sow seeds again in late summer, six to eight weeks before the average first fall frost. This timing allows plants to mature in the cooling temperatures of September and October, resulting in sweeter leaves.