Green Circle Growers Blog

Stock up on Marigolds to Protect Vegetable Plants

Green Circle Growers - Thursday, July 07, 2011

Summer’s barely begun, but garden centers are already marking down popular annuals. If you’re a vegetable gardener, this is the perfect time to stock up on Marigolds (Tagetes). These colorful, low-growing annuals with the tightly-ruffled pom-pom heads are the super hero of vegetable gardens.

A cheerful plant that grows in low bushy mounds, marigolds are studded with a firecracker mix of bright yellow, orange and red multi-petalled blossoms. A profusion of colorful blooms makes marigolds a popular choice for flower garden borders, but this plant leads a clandestine life, also serving as the vegetable gardener’s secret weapon.

Their jaunty appearance belies their super hero powers, but marigolds protect vegetable plants with a one-two punch worthy of any super hero. Above ground, the vaguely citronella-like fragrance emitted by the plant’s foliage and flowers deters rabbits, white flies and numerous other unwanted pests. Below ground, marigolds release a chemical through their roots that kills harmful nematodes, microscopic worms that live in the soil, preventing these organisms from attacking and damaging vegetable crops.

Tomato plants are particularly susceptible to nematodes. Numerous nematode species feed on either the roots or stems of tomato plants. A nematode infestation can permanently damage tomato plants, increasing their vulnerability to other pests and diseases, severely decreasing crop yields and often killing the plants. Planting tomatoes in the same spot for too many consecutive seasons can allow nematode populations to proliferate, sometimes rending the vegetable plot unusable for several seasons. Regular crop rotation is necessary to control the growth of nematode populations. To help prevent nematode infestations in your vegetable garden, plant marigolds with vegetables and choose nematode-resistant tomato varieties such as Big Beef, Empire, Champion, Super Beefsteak and Small Fry cherry tomatoes.

Photo by: Jim Mead