Marigolds (Tagetes genus) are favored annual flowers known for their ease of cultivation and vibrant, cheerful colors. They provide consistent blooms from spring until the first frost, making them garden staples. These resilient plants are often used in vegetable gardens for their reputed ability to deter certain pests, such as nematodes. Successfully growing these flowers from seed requires a few specific steps to ensure optimal plant health and maximum flowering.
The Recommended Seed Count
The standard recommendation is to plant between two and three marigold seeds in each designated planting spot. This deliberate redundancy accounts for the natural variability in seed viability and germination rates, which can be affected by factors like seed age or inconsistent soil moisture. Planting a small cluster of seeds ensures that at least one seedling will emerge and thrive in that location.
This initial over-planting is a temporary measure designed to guarantee a full, evenly spaced flower bed. The intention is to select the single strongest plant from the group once they have established themselves. Varieties like African marigolds (Tagetes erecta) and French marigolds (Tagetes patula) need adequate space to develop their full, bushy form. This approach eliminates empty patches that would otherwise result from a failed single-seed planting.
Planting Depth and Spacing
The seeds should be placed at a shallow depth to facilitate germination. Marigold seeds should be covered with approximately one-quarter inch of fine soil, as planting them too deep prevents the seedlings from reaching the surface. This shallow depth secures the seeds while still allowing the emerging sprout to quickly access sunlight. After sowing the seeds, gently press the soil surface down to ensure good seed-to-soil contact, which is necessary for moisture absorption.
The distance between these groups of seeds is determined by the mature size of the specific marigold variety. French marigolds, being smaller and more compact, require a horizontal spacing of 8 to 10 inches between planting spots. Larger African marigolds grow taller and wider, making it necessary to space their seed groupings 10 to 12 inches apart to allow for proper air circulation and root development.
Why Thinning is Necessary
Planting multiple seeds per hole makes the subsequent step of thinning mandatory for healthy plant development. Thinning is the process of removing excess seedlings to ensure that only the strongest plant remains in the designated space. Without this step, the multiple seedlings will compete intensely for the available light, water, and nutrients in the small patch of soil. This competition results in weak, spindly, and less floriferous plants.
The correct time to perform this task is when the marigold seedlings have developed their first set of “true leaves,” which appear after the initial, round cotyledon leaves. You should carefully select the most robust seedling that appears to be growing the fastest and has the thickest stem. To remove the weaker competitors, use a small pair of sharp scissors or nail clippers to snip the unwanted seedlings at the soil line. It is important to cut the stems rather than pulling the plants out of the soil, as pulling risks disturbing or damaging the root system of the keeper seedling. This technique ensures that the chosen plant can immediately access all the available resources to grow into a strong, bloom-producing specimen.