By Jessica Carlson 

OTC Master Gardener Intern

Autumn cleanup plays an important role in keeping diseases and pests under control for next year. A clean garden is a healthy garden, and many problems can be avoided simply by removing and properly disposing of infected plant material. The University of Minnesota Extension reminds gardeners that fall is the time to break pest and disease cycles by clearing away diseased leaves, fruit, and stems that can harbor insects and pathogens through winter. Compost only healthy material, and discard anything that looks diseased in the trash, not the compost pile. 

Apples, plums, raspberries, and other fruits often drop leaves and fruit that can carry diseases such as apple scab, fire blight, and gray mold. These should be raked up and discarded before snow arrives. Prune out dead or diseased branches once the leaves have fallen so you can clearly see the structure of the tree or bush. Do not leave any fallen fruit on the ground because it can attract overwintering insects such as codling moths and spotted wing drosophila. An early spring pruning  helps air circulate freely through the branches and reduces moisture, which in turn limits the spread of fungal diseases. 

Vegetable gardens also benefit from a good fall cleaning. Once the harvest is complete, pull up old tomato, squash, and cucumber plants, as these are common hosts for diseases like powdery mildew and blight. Remove stakes and cages and wash them with a mild bleach solution before storing them for winter. To avoid problems with soil-borne diseases, rotate crops next year so that the same family of vegetables is not planted in the same place. Spreading a light layer of compost or shredded leaves over cleared beds can improve soil health and structure while reducing erosion during the winter months.

Some perennials benefit from leaving the stems and seed heads standing for winter interest and wildlife, but plants that show signs of disease should be cut back and the debris removed. Peonies, bee balm, and phlox, often carry fungal diseases that survive in old stems and leaves. Cutting these back to the ground helps prevent the spread of powdery mildew and botrytis.  Healthy perennials that are left standing will provide shelter for beneficial insects and food for birds, adding both life and beauty to the winter garden.

Sanitizing your tools is another key step to maintaining a healthy garden. Dirty tools can transfer disease from one plant to another without you realizing it. Before storing them for the season, wash tools with warm, soapy water and then disinfect them using a 10 percent bleach solution or rubbing alcohol. Dry them thoroughly and apply a light coat of oil to prevent rust. Sharp, clean tools make pruning and digging easier and safer, and they protect your garden’s long-term health.  Visit www.extension.umn.edu/planting-and-growing-guides/managing-plant-diseases-home-garden for more information.