Vegetable Seed Germination Times

Vegetable seeds, on average, germinate in about seven to 10 days. A few, such as radishes and broccoli, may germinate in three days; carrots and parsnips may take several weeks to appear. Extreme soil temperatures may slow or curtail germination, as well as soil that is too dry or too wet. Follow the recommendations on the seed packet for planting depths and space, unless your soil is heavy clay. Then reduce planting depth slightly.

Sow cool-season crops, such as lettuce, kale, spinach, onions and broccoli, directly into the garden up to four weeks before the last expected frost. These crops germinate within three to 10 days under optimal conditions and tolerate daytime temperatures as low as 40 degrees Fahrenheit. Plant semihardy vegetables, such as turnips, carrots, cauliflower, parsnips and potatoes, two weeks later. These crops typically take seven to 10 days, although carrots and parsnips take longer. Carrots germinate in 10 to 15 days; parnsips in 15 to 25 days. Wait to plant beans, corn and melon until the soil is warm and all danger of frost has passed. These seeds germinate within six to 10 days under optimal conditions.

Some crops, such as peppers and tomatoes, take so long to grow that they won't mature before the first frost if sown from seed in the garden. Start these crops indoors four to six weeks before the last frost. Plant tomato and pepper seeds in seed starting trays, waxed milk cartons or even yogurt cups. Sow the seeds 1/8 inch deep in a soilless starting mix. Moisten the soil with a spray bottle and cover the seeds with plastic wrap until they germinate. Tomatoes germinate in six to 14 days; peppers in 10 to 20 days.

When seeds germinate is based, in part, on the temperature of the soil. In cold soils, many seeds such as bean seeds are slow to germinate, or may even rot, never germinating at all. Read the seed packet and wait to plant seeds until the soil is adequately warm. Conversely, cool-season plants, such as lettuce, kale and spinach, germinate best in cool soils and may not germinate well when planted midsummer for a fall harvest. Store these seeds in the refrigerator for two weeks prior to planting to increase the odds of successful germination.

Although some plants are drought tolerant once established, all seeds need moist soil to germinate. Moisten the soil before planting vegetable seeds and water lightly after planting, as well. Water at least weekly or as needed to keep the soil moist, but not soggy, which may cause seeds to rot. Don't allow the soil to dry out because it forms a crust that is difficult for the growing plant to emerge through. Use a light hand so you don't wash seeds away.