There are three common types of marigolds: French (Tagetes patula), African (Tagetes erecta), and Signet (Tagetes tenuifolia). French marigolds are compact (~6-12″ height) with either single or double flowers. African marigolds are taller (~3-4′ height), have a strong upright habit and typically produce large double flowers. Signet marigolds are the smallest in size (<6″ height), have a mound-like growth habit, and have edible flowers often with a single row of petals.

Zone: 2-11
Light: Full sun (6 – 8 hours of direct sun)
Soil: Well-drained, pH 6-7
Water: Moderate; ensure even moisture in soil but avoid waterlogging
Fertilization: Low feeders; does not require heavy fertilization

Marigolds can be direct seeded into garden soil when soil temperatures are >65°F or seeds can be started indoors ~8 weeks prior to transplanting outdoors after the threat of frost has passed. Pinch the tips off of the plant to encourage a bushier growth habit. After flowering begins, deadhead old blooms to encourage new blooms and reduce disease prevalence.

Cover cropping with French marigolds has been shown to reduce the number of root-knot nematodes in soil. French marigolds release a chemical (alpha-terthienyl) that is highly toxic to root-knot nematodes and prevents their eggs from hatching. Additionally, root-knot nematodes are not able to live and develop properly within marigold roots.

Marigolds are native to Mexico and Central America.

Marsh Marigold (Caltha palustris) is an herbaceous perennial in the Ranunculaceae family. The common name is misleading because Marsh Marigold is not related to, nor resembles, Tagetes spp.

Calendula (Calendula officinalis) is sometimes referred to as Pot Marigold. Although both C. officinalis and Tagetes spp. belong to the Asteraceae family, these two plants should not be confused.