Low Temperature for Marigolds

Features

• Bright, bold marigolds are a traditional gardening favorite. Whether planting showy, carnation-like African types or small, five-petaled French varieties, gardeners can count on marigolds to fill flower beds, garden borders, planter boxes and hanging baskets with clusters of cheerful, easy-to-grow flowers and masses of deeply-cut, dark green, fragrant foliage. In addition to adding color and texture to the landscape, the vivid marigold blossoms attract beneficial insects, such as ladybugs and lacewings, while deterring the presence of unwanted pests.

Germination

• Marigolds are heat-loving plants and, as such, should not be placed in the garden until the soil has thoroughly warmed. Cold weather can kill young seedlings and seeds; for the best results, wait until the average temperature is at least 70 to 75 degrees Fahrenheit during the daytime and the overnight lows are no less than 50 degrees. Though marigolds sprout in a week to 14 days, it may take several weeks for flowers to emerge; those who live in areas with a short summer season may want to start seeds indoors four to six weeks before the anticipated date of the final frost.

Growth and Development

• Marigolds do best when planted in sunny locations. Once established, these hardy, robust plants bloom profusely all summer long. Though marigolds are drought-tolerant sun-lovers, they do wilt a bit in the afternoon heat. As a result, flower production tends to slow during periods of hot, humid weather. Additionally, flower production begins to decelerate when autumn weather arrives. To extend the flowering season, cover the plants in the evening if the overnight low is expected to drop below 50 degrees Fahrenheit, and surround the bases of the plants with sheets of black plastic, as this will help keep the soil warm.

Pot Marigolds

• While they can grow as far north as coastal Alaska, marigolds are essentially tropical in nature. Consequently, they thrive in hot locations and southern gardens. Those who live in the North may have better luck with pot marigolds, or calendula. These low-maintenance flowers look almost exactly like true marigolds, but they are cool-season annuals, rather than warm-season plants. This means they grow best in cool climates, and wither when exposed to summer's heat. Sow pot marigolds directly into the garden before danger of frost has passed, or in the fall for early spring germination.