PH of Soil for Growing Marigolds

Features

• Marigolds are easily identified by their familiar, warm-colored blossoms. Whether they bear the archetypal, yellow, carnation-shaped blooms or flat-headed, orange-and-yellow, single petals, the popularity of this gardening annual keeps it very much in the public eye. These beloved, low-maintenance plants flourish under a wide variety of conditions, blossoming nonstop from early summer thorough light frosts. Though the flowers themselves tend to be scentless, the blooms rest upon deep green, sharply-cut foliage that bears a strong, pungent aroma.

Classic Marigolds

• While there are a multitude of marigold cultivators, classic marigolds are generally placed in one of three groups: African, French or Signet. African marigolds are known for their 3- to 6-inch carnation-like blooms. Though they produce fewer flowers than other types of marigolds, the blossoms are larger, as are the plants that bear them. French marigolds are small, low-growing plants that produce flat, 2-inch, single or double petal flowers. While the flowers of these bushy plants are smaller than African varieties, they hold up better in rainy weather and are, therefore, the ideal choice for areas known for wet summer weather. Signet marigolds are dainty plants that produce mounds of fluffy foliage and clusters of delicate flowers. The single petal blooms are similar to French marigolds, but they are smaller and less robust.

Soil pH

• Though all marigolds are robust plants that tolerate a wide variety of climatic conditions, they thrive when set in acidic soils with a pH of 5.8 to 6.5. To lower the pH at a given site, incorporate coffee grounds into the soil before planting the flowers. When exposed to water, the coffee grounds release their naturally-acidic brew into the surrounding soil, lowering the pH and increasing acidity. Alternatively, the raise the pH, mix wood ashes into the soil at the planting site, replacing up to 1/3 of the excavated dirt. As the wood ashes decompose, they release calcium into the soil, raising the soil pH and reducing acidity.

Pot Marigolds

• Pot marigolds are not marigolds at all. They are cool-season annuals and members of the Calendula family. They are often referred to as marigolds simply because they produce flowers that are remarkably similar in size and structure. Unlike heat-loving marigolds, these plants bloom best during cool spring weather, and wither and die under the rays of the summer sun.