Asked October 20, 2014, 4:16 PM EDT

I grew tomatoes in a container this summer. I had a mild bout with hornworms. Is that soil safe to return to the garden? If not, how can I safely dispose of the soil?

Delaware County Pennsylvania master gardener program soil contamination tomatoes for pots and small spaces

1 Response

Hello, and thanks for using the Ask an Expert System,

Hornworms overwinter in the pupal stage in the soil. If you only had a mild infestation of hornworms in your tomato containers, and removed the adult caterpillars, there should be no pupae in the soil. To be absolutely sure there are no pupae in the soil thorough mixing the soil in the container before dumping should destroy any pupae.

You can read more about controlling tomato hornworms in the fact sheet Tomato Hornworms in Home Gardens. The fact sheet is available at

If you have additional questions you can speak to a Penn State master Gardener in your county. Information on how to contact the Delaware County Hortline is available at

Delaware County Penn State Extension
Address: 20 Paper Mill Road, Springfield, PA 19064
Phone: 610-690-2655
Office Hours: Monday-Friday 8:30 a.m. - 4:30 p.m