Question: I noticed knots on the roots of my bean plants when I took them out of the garden. Are those anything I should worry about? The plants grew and produced really well.
Answer: There are two candidates, one good and one bad. Beans are legumes, and, as such, they have nitrogen-fixing bacteria that form nodules on the plants’ root systems. They convert gaseous nitrogen from the soil-borne air into a form that plants can utilize through their roots. Those nodules you have seen may be nothing more than that. However, beans are also susceptible to nematodes, the microscopic soil-borne worms that attack many plants’ roots. Galls will form on the roots, and the plants will usually be stunted thereafter. Having the soil tested for presence of root-knot nematodes is the only way you can be sure. Your county Extension office has all the details.